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Climate Hustle

John Abraham

 

Recent blog posts


Our oceans broke heat records in 2018 and the consequences are catastrophic

Posted on 17 January 2019 by John Abraham &

Last year was the hottest ever measured, continuing an upward trend that is a direct result of manmade greenhouse gas emissions.

The key to the measurements is the oceans. Oceans absorb more than 90% of the heat that results from greenhouse gases, so if you want to measure global warming you really have to measure ocean warming.

There are other ways to measure climate change, but none are as convincing as the oceans. Air temperatures are most commonly reported in the media as evidence of global warming, but the problem with these is they are very erratic. While there is certainly a long-term trend of higher air temperatures, any given year may be warmer or colder than the last.

So oceans are key, and they are telling us a clear story. The last five years were the five hottest on record. The numbers are huge: in 2018 the extra ocean heat compared to a 1981-2010 baseline amounted to 196,700,000,000,000,000,000,000 joules. The current rate of ocean warming is equivalent to five Hiroshima-size atomic bombs exploding every second.

The measurements have been published in the journal Advances in Atmospheric Sciences in an article by Lijing Cheng, the lead author, and his colleagues from the Institute for Atmospheric Physics in China. His collaborators, of which I am one, included researchers from around the world. The article charts ocean heat back to the late 1950s, showing a steady increase.

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2 comments


Some of the countries leading on climate change might surprise you

Posted on 24 October 2018 by John Abraham &

Countries that may not be thought of as climate leaders are emerging at the front-lines on responding to climate change.

One great example is Iran.  I have the fortune of performing water-use research with a number of scientists in Iran.  And I can assure you they are thinking about, planning, and taking action to reduce the impacts of climate change and ecological destruction.

One example of an Iranian leader is Dr. Mohammad Taghi Sattari who is an Associate Professor of water engineering at the University of Tabriz.  He recently wrote a report about an effort in Iran to handle their water availability crises.  It probably doesn’t surprise people that Iranians think about water availability; it is a country with limited rainfall.  And the concurrence of three issues (water management, growing population, and climate change) make this is particularly challenging problem. 

In 2017, the Iranian government released a report from the Strategic Studies Center that showed water availability is viewed as the second-most important national issue.  Statistical data from the Iranian government’s Power Ministry and from the World Bank predict that Iran is soon to enter a broad and extensive water crisis. If the crisis is not properly managed, there will be both direct and indirect economic costs, social upheaval, and security consequences.

According to the published data, in 2014, the annual rainfall in Iran averaged 228 mm (less than a foot).  This is 1/5th the world-average rainfall. As a country, Iranian’s rainfall put them in the 163rd position.  Dr. Sattari believes that even though the amount of rainfall in Iran is very low, proper management could enable it to match the needs of the country.

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1 comments


Victims of Hurricane Michael voted for climate deniers

Posted on 11 October 2018 by John Abraham &

Floridians are staring down a very powerful Category 4 typhoon that is causing extensive damage.  The high winds, heavy rains, and storm surge will cost billions of dollars.

We know that climate change is making these storms stronger.  The storms feed off of warm ocean waters, and those waters are much warmer now because of climate change. I have written about the science in more detail here and here.  But basically, Michael strengthened because it passed over really warm waters.  Waters that were hotter because of human-caused warming.

ocean temps

Water ocean temperatures around Florida as Hurricane Michael evolved. Illustration: NASA EOSDIS/LANCE

Predictably, the hurricane strengthened as it hit shore.  As I write this, Michael is coming ashore and the pressure is still falling (low pressures in a hurricane signify a stronger storm).  It appears that Michael may have the third-lowest pressure for a hurricane hitting the USA.

IR Michael

Infrared image of Hurricane Michael Photograph: NASA/NOAA/UW-SSEC-CIMSS, William Straka III

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7 comments


New research shows the world’s ice is doing something not seen before

Posted on 26 September 2018 by John Abraham &

In this warming world, some parts of the planet are warming much faster than others.  The warming is causing large ice bodies to start to melt and move rapidly, in some cases sliding into the ocean. 

This movement is the topic of a very new scientific study that was just published in the journal Earth and Planetary Science Letters.  The Arctic is warming much faster than other parts of the planet and the ice there is showing the signs of rapid warming.  This fact has serious consequences. First, melting ice can cause sea levels to rise and inundate coastal areas – it also makes storms like hurricanes and typhoons more destructive.  Melting ice also causes a feedback loop, which can cause more future warming and then more ice loss.

It should be noted that there are different types of ice.  Some ice floats on water and is called sea ice.  When it melts, the ocean water level hardly budges because the ice is already in the sea displacing liquid water.  But, sea ice is really important for this feedback loop I mentioned above.

Other ice is on land and may be a large ice sheet or a smaller glacier.  These ice bodies sit atop the land and “rest” there.  In some cases, they extend out off the land and into the ocean where they partly float on liquid water.  When this land ice melts, the liquid flows into the oceans and can cause significant ocean level rising.

So, the importance of ice depends on what type it is, where it is located, and how fast it is melting. And this brings us to the new paper.

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3 comments


Warming oceans are changing the world's rainfall

Posted on 12 September 2018 by John Abraham &

Global warming means truly global warming. The atmosphere, the oceans, and the ground are all warming. As a result, ice is melting, seas are rising, storms are getting more severe, and droughts are getting worse. But these things are not happening in isolation. The tricky thing about the climate is that things are connected all across the globe. And those connections are revealing changes that may not be obvious at first glance.

One such change was exposed in a recent paper published in the journal Environmental Research Letters by a team of top scientists from China and Brazil, an instructive video is available here. The scientists focused their study on the Amazon rainforest. There, the year is broken into “wet” and “dry” seasons. The researchers wanted to know how rainfall has changed during the wet seasons over the past few decades.

What they found was astonishing – the rain in this tropical rainforest has increased 180–600 mm (7–24 inches). They learned about the increase in wet-season rainfall by reviewing old weather data – information from rain gauges for example. They also used satellite measurements to complement the rain gauge readings. The trend they found was clear – the rains are increasing.

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Global warming is intensifying El Niño weather

Posted on 29 August 2018 by John Abraham &

As humans put more and more heat-trapping gases into the atmosphere, the Earth warms. And the warming is causing changes that might surprise us. Not only is the warming causing long-term trends in heat, sea level rise, ice loss, etc.; it’s also making our weather more variable. It’s making otherwise natural cycles of weather more powerful.

Perhaps the most important natural fluctuation in the Earth’s climate is the El Niño process. El Niño refers to a short-term period of warm ocean surface temperatures in the tropical Pacific, basically stretching from South America towards Australia. When an El Niño happens, that region is warmer than usual. If the counterpart La Niña occurs, the region is colder than usual. Often times, neither an El Niño or La Niña is present and the waters are a normal temperature. This would be called a “neutral” state.

The ocean waters switch back and forth between El Niño and La Niña every few years. Not regularly, like a pendulum, but there is a pattern of oscillation. And regardless of which part of the cycle we are in (El Niño or La Niña), there are consequences for weather around the world. For instance, during an El Niño, we typically see cooler and wetter weather in the southern United States while it is hotter and drier in South America and Australia.

It’s really important to be able to predict El Niño/La Niña cycles in advance. It’s also important to be able to understand how these cycles will change in a warming planet. Fortunately, a study just published in Geophysical Research Letters helps answer that question. The authors include Dr. John Fasullo from the National Center for Atmospheric Research and his colleagues.

El Niño cycles have been known for a long time. Their influence around the world has also been known for almost 100 years. It was in the 1920s that the impact of El Niño on places as far away as the Indian Ocean were identified. Having observed the effects of El Niño for a century, scientists had the perspective to understand something might be changing. 

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1 comments


Humans are pushing the Earth closer to a climate cliff

Posted on 15 August 2018 by John Abraham &

A new paper, just published in the Proceedings of the National Academy of Sciences has received a lot of media attention. The attention is justified because the paper paints a very grim picture of the climate and what humans may be doing to it. In particular, the authors of this study tried to determine the trajectory that the Earth is on so we can predict what the future climate will be.

There are many really important insights from this paper. The authors wanted to know how feedbacks in the Earth’s climate will play a role in shaping the climate in the future. By feedbacks, we mean a change in one part of the climate that then causes another change, which in turn may cause another change, and so on, potentially setting up chain reactions.

Feedbacks are really important because they are changes that the natural system makes without being caused directly by humans.

For example, melting ice is one feedback, particularly in the Arctic. Humans have emitted greenhouse gases that have caused the Earth to warm. As the Earth warms, ice melts; as ice melts, it means there is less white reflective cover on the Earth surface. In fact, a lot of this ice melting is happening in the Arctic. Instead of having a white surface that reflects sunlight, we have open ocean water that absorbs sunlight. Consequently, melting of ice leads to more absorbed sunlight which then leads to more melting of ice – a reinforcing cycle, as illustrated below.

diagram

 Melting ice positive feedback cycle diagram. Illustration: John Abraham

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18 comments


Pollution is slowing the melting of Arctic sea ice, for now

Posted on 7 August 2018 by John Abraham &

The Arctic is one of the “canaries in the coal mine” for climate change. Long ago, scientists predicted it would warm quicker than other parts of the planet, and they were right. Currently, the Arctic is among the fastest-warming places on the planet. Part of the reason is that as the Arctic warms, ice melts and ocean water is uncovered. The ocean is darker than ice so it in turn absorbs more sunlight and increases its warming. This is a feedback loop.

Another reason is that the Arctic doesn’t get that much sunlight so increased energy from the atmosphere has a bigger influence there than it would have elsewhere.

Scientists have looked to the Arctic for clues and hints of human climate change over the past decades. The fact that the Arctic is warming has led to a 70% reduction in the volume of summer sea ice – an enormous loss of ice.

sea ice

 Decline in September Arctic ice extent (not volume). Illustration: Nasa

A recent paper just published in the Journal of Climate by the American Meteorological Society takes an in-depth look at how fast the Arctic ice is melting and why. According to the paper, the authors completed a detection and attribution study of Arctic sea ice decline from 1953 to 2012. That is 60 years of data that tell the picture of climate change. The “detection” part of this study was about detecting what long-term trends are apparent over these six decades. The “attribution” part of the study is figuring out what is the cause of the trends.

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6 comments


Scientists detect a human fingerprint in the atmosphere's seasonal cycles

Posted on 23 July 2018 by John Abraham &

We know that humans are causing Earth’s climate to change. It used to be that “climate change” mostly referred to increasing temperatures near the Earth’s surface, but increasingly, climate change has come to mean so much more. It means warming oceans, melting ice, changing weather patterns, increased storms, and warming in other places.

A recent study has just been published that finds ‘fingerprints’ of human-caused warming someplace most of us don’t think about – in the higher atmosphere. Not only that, but these scientists have found changes to the seasonal climate – how much the temperature varies from winter to summer to winter – and the changes they found matched expectations. 

The paper was authored by a top group of scientists including Benjamin Santer, Stephen Po-Chedley, Mark Zelinka, Ivana Cvijanovic, Celine Bonfils and Paul Durack from Lawrence Livermore National Laboratory; Carl Mearsand Frank Wentz from Remote Sensing Systems; Qiang Fu from the University of Washington; Jeffrey Kiehl from the University of California, Santa Cruz; Susan Solomon from MIT; and Cheng-Zhi Zou from the University of Maryland. These are literally the best of the best climate scientists studying Earth’s atmosphere.

So, how did the scientists carry out their research?

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Rising ocean waters from global warming could cost trillions of dollars

Posted on 12 July 2018 by John Abraham &

Ocean waters are rising because of global warming. They are rising for two reasons. First, and perhaps most obvious, ice is melting. There is a tremendous amount of ice locked away in Greenland, Antarctica, and in glaciers. As the world warms, that ice melts and the liquid water flows to the oceans.

The other reason why water is rising is that warmer water is less dense – it expands. This expansion causes the surface of the water to rise.

NASA SLR

Rising oceans are a big deal. About 150 million people live within 1 meter (3 feet) of sea level. About 600 million live within 10 meters (33 feet) of sea level. As waters rise, these people will have to go somewhere. It is inevitable that climate refugees will have to move their homes and workplaces because of rising waters. 

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2 comments


Trump should inspire us all, but not in the way you might guess

Posted on 27 June 2018 by John Abraham &

Scientists like me – and really, everyone – can learn from President Donald Trump’s mastery of viral messaging.

True, he has turned the United States into a pariah nation, one reviled for ripping immigrant children from their parents and from withdrawing from our only real chance at stabilizing the climate, the Paris Accord

But Trump’s success at creating and maintaining a political base is not because of his incoherent policies. It is solely because he is able to communicate with people in ways that that evoke emotion, go viral, and make people think he understands them.

The way super-communicators like Jesus, Shakespeare, Oprah, or even Trump work their magic was unpacked by Dr. Joe Romm in a must-read book, How To Go Viral and Reach Millions.

The cover of ‘How to Go Viral and Reach Millions’ 

The cover of ‘How to Go Viral and Reach Millions’

The job for scientists, for all of us, is to learn the techniques that make our messages clicky and sticky, but use the techniques in a way that keeps the science true and the facts straight. Be a Jedi, not a Sith Lord.

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22 comments


The legal fight to leave the dirtiest fossil fuels in the ground

Posted on 14 June 2018 by John Abraham &

Tar sands are the dirtiest fossil fuels. These are low-quality heavy tar-like oils that are mined from sand or rock. Much of the mining occurs in Alberta Canada, but it is also mined elsewhere, in lesser quantities.

Tar sands are the worst. Not only are they really hard to get out of the ground, requiring enormous amounts of energy; not only are they difficult to transport and to refine; not only are they more polluting than regular oils; they even have a by-product called ”petcoke” that’s used in power plants, but is dirtier than regular coal.

This stuff is worse than regular oil, worse than coal, worse than anything. Anyone who is serious about climate change cannot agree to mine and burn tar sands. To maintain climate change below critical thresholds, tar sands need to be left in the ground.

This fact is what motivated me to testify to the Minnesota Public Utilities Commission last November, to inform my state’s ruling commission about the impact of tar sands on the climate. Canadian energy company Enbridge has petitioned to put a pipeline through my state to carry this dirty tar to refining sites on the coast. 

The proposed pipeline is called “Line 3.” The pipeline would carry approximately 760,000 barrels per day – the new pipeline would make it easier and cheaper for the oil companies to transport tar sands and consequently, would boost their bottom line. We already move over two million barrels per day through Minnesota in Enbridge pipelines. This new pipeline would encourage them to extract and sell more tar sands.

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10 comments


Tiny shrimp could influence global climate changes

Posted on 7 June 2018 by John Abraham &

When we think of global warming and climate change, most of us ignore the impacts that animals have on the environment. Climate affects animals, but is the reverse true? Can animals affect the climate?

I don’t know how to answer that question definitively, but I was fortunate enough to read a very recent paper from a top fluid dynamics research team from Stanford. The team, led by Dr. John Dabiri, is well known for their work on bio-inspired flow. Part of what they study is the influence of living organisms on fluid flow, especially flow of water in the oceans.

This team’s recent work deals with something called aggregate motion of swimmers and it was published in Nature this year. The researchers wanted to know what happens when thousands (or millions) of small creatures swim in a single direction. Can the wakes they create add up to a larger scale motion and can these motions affect the ocean waters that they swim through?

Flow pattern caused by krill motion.

Flow pattern caused by krill motion. Illustration: Houghton et al. (2018); Nature

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2 comments


Global warming made Hurricane Harvey more destructive

Posted on 23 May 2018 by John Abraham &

Last summer, the United states was pummeled with three severe hurricanes in rapid succession. It was a truly awesome display of the power of weather and the country is still reeling from the effects. In the climate community, there has been years of research into the effect that human-caused global warming has on these storms – both their frequency and their power. 

The prevailing view is that in a warming world, there will likely be fewer such storms, but the storms that form will be more severe. Some research, however, concludes that there will be both more storms and more severe ones. More generally, because there is more heat, there is more activity, which can be manifested in several ways.

Regardless, there is very little doubt that a warmer planet can create more powerful storms. The reason is that hurricanes feed off of warmer ocean water. In order to form these storms, oceans have to be above about 26°C (about 80°F). With waters that hot, and with strong winds, there is a rapid evaporation of moisture from the ocean. The resulting water vapor enters into the storm, providing the energy to power the storm as the water vapor condenses and falls out of the storm as rain.

As a large hurricane passes over warm water, it sucks in heat not only from the top layer of water but also from quite deep in the ocean, at least 160 meters (approximately 525 feet) or more. The main way heat is pulled out of the ocean is through the aforementioned evaporation process. There are also smaller effects from mixing the ocean waters and blocking sunlight to the ocean. Basically, when a hurricane passes over warm waters, the ocean “sweats” and cools off – a process enabled by the strong winds. The image below shows this evaporation and condensation process.

diagram

Diagram of evaporation and rainfall within a hurricane. Illustration: Trenberth et al. (2018), Earth's Future

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Global warming is melting Antarctic ice from below

Posted on 9 May 2018 by John Abraham &

We all know intuitively that in a warmer world there will be less ice. And, since the North and South Pole regions contain lots of ice, anyone who wants to see evidence of climate change can look there.

But beyond this simplistic view, things can get pretty complex. First, it’s important to recognize that the Arctic and the Antarctic are very different places. In the Arctic, almost all the ice is floating on water – there is very little land. So, we talk about ‘sea ice’ in the north, formed from frozen sea water. On the other hand, Antarctica is a massive land mass that is covered by ice formed from snowfall (called an ‘ice sheet’). There is some floating ice around the perimeter of the land, but the vast majority of Antarctic ice is on land.

This difference not only affects how these regions response to climate change, but it also impacts their importance. We know that when floating ice melts, the ocean levels will not rise, because the ice was already floating in the water. But, when land ice melts, the liquid water flows into the ocean and causes the water levels to rise. So, at least from a sea-level perspective, land ice is more important than floating ice.

There are other differences between the north and south. One feature of the south is that there is a strong current that travels around Antarctica and partially shields it from waters elsewhere in the ocean. The Nasa Jet Propulsion Laboratory provides a good summary of some of the differences between the poles.

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America's best scientists stood up to the Trump administration

Posted on 25 April 2018 by John Abraham &

Anyone who has read this column over the past five years knows that I tend to be unfettered in my criticism of people who lie and distort climate science to further their political ideologies. At the same time, I believe that the majority of climate sceptics are not willfully wishing to damage this precious Earth that we call home. I believe that there are common areas we can all agree on to take meaningful action to protect the Earth’s environment and build a new energy future; even for people who do not understand climate change or climate science.

But with the election of Donald Trump and his ushering in people who are openly hostile to the planet and future generations, my position has been strained (to say the least). We have had more than a year to observe President Trump’s efforts to roll back Obama-era regulations on pollution from coal plants, weaken pollution standards for motor vehicles, become the only country in the world to reject the Paris climate accord, and gut our climate science budget so that we become blind to what is actually happening. 

We have to believe Trump when he says that he thinks climate science is a hoaxand we have to expect he will act according to this belief. Under Trump, the USA has become a pariah nation. It hurts me to say this, because I love the USA and what it stands for. But regarding the environment, we are the worst of the worst.

Some people will claim I am “unpatriotic” or “unAmerican” to criticize my country. My response is, I am honest. A patriot is someone who loves their country and wants their country to meet the ideals that are the foundation of that nation. Patriotic means you want your country to be better; you want your country to make a positive impact. I believe that turning a blind eye to your country’s faults is a most deeply unpatriotic act. I want my country to excel, I want my country to lead, I want my country to be a shining light on a hill. If my country fails or falters in that endeavor, I will work tirelessly to correct our path. That, in my mind is patriotism.

President Trump has installed radical science deniers in his administration to obstruct climate science research, to stop development in clean and renewable energy (the economic growth engine of the future), and to attack scientists for doing their jobs. Among Trump’s most harmful acts was to appoint Scott Pruitt to head the EPA. Scott Pruitt does not understand even basic climate science, and he doesn’t comprehend that climate change will be bad for human society

But it isn’t just Trump and Pruitt that are a problem. Everyone in the Trump administration seems hell-bent on damaging the planet. Recently, climate change denier Jim Bridenstine was confirmed by Senate Republicans to lead Nasa – one of the two most important climate science organizations in the country. Trump has brought with him a swamp filled with anti-science staff whose goal is to handicap the US and permanently remove us from any leadership role in the world.

To be clear, Trump, Pruitt, the entire administration, and those who support him will inherit a terrible legacy that we will not forget. These people will be known for willfully trying to destroy the planet that we rely on for health and prosperity.

Despite the attacks from the Trump/Pruitt Administration, some scientists have begun to speak out. This speaking out takes courage. I have the luxury of being unbridled in my work. My livelihood does not depend on federal research grants; I have no boss in Washington DC that can threaten me; Scott Pruitt cannot attack me; nor can President Trump. For a scientist like me, speaking out is low-risk.

But many of my colleagues are not so fortunate. Many of my colleagues, who have dedicated their lives to understanding the Earth’s environment, are employed by Washington. That is, they are able to carry out research by obtaining federal grants. These grants pay for their instruments (satellites, sea level gauges, weather balloons, supercomputers, etc.), their offices, salaries, and so forth. And when these scientists speak out, it is an act of courage and selflessness.

This week, many of these scientists have spoken out. In an open letter, over 600 scientists from the prestigious National Academy of Sciences (America’s best scientists) wrote the following:

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Glacier loss is accelerating because of global warming

Posted on 18 April 2018 by John Abraham &

With global warming, we can make predictions and then take measurements to test those predictions. One prediction (a pretty obvious one) is that a warmer world will have less snow and ice. In particular, areas that have year-round ice and snow will start to melt.

Alpine glaciers are large bodies of ice that can be formed high in mountains, typically in bowls called cirques. The ice slowly flows downwards, pulled by gravity, and is renewed in their upper regions. A sort of balance can occur where the loss of ice by melting or flowing at the bottom is equal to the gain of snow and ice by precipitation.

As the Earth warms, the melt line moves upwards so that the glacier melts faster and faster at the bottom, shortening the glacier and reducing its mass. Ultimately, the melted water flows into streams and rivers and ends up in the oceans, contributing to accelerating sea level rise.

While glaciers are interesting from an intellectual standpoint, they are also important to ecosystems and society. For example, the rate of glacier melt affects downstream water levels, river flowrates, and the water available for human use. So, it would be really important for us to be able to predict what will happen with glaciers in the future and plan for how water availability will change.

Of the groups that track glaciers, my favorite is the World Glacier Monitoring Service, which publishes a survey of the mass changes from selected glaciers around the world, available here and summarized below. The graph shows changes to the mass of the glaciers that are monitored, measured in millimeters of equivalent water.

glacier mass

Changes to water content of glaciers. Illustration: World Glacier Monitoring Service

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Scientists examine threats to food security if we meet the Paris climate targets

Posted on 3 April 2018 by John Abraham &

We have delayed action for so long on handling climate change, we now can no longer can “will it happen?” Rather we have to ask “how bad will it be?” and “what can be done about it?” As our society thinks about what we should do to reduce our carbon pollution and the consequences of electing science-denying politicians, scientists are actively studying the pros and cons of various emission reductions. 

Readers of this column have certainly heard about temperature targets such as 1.5°C or 2°C. These targets refer to allowable temperature increases over pre-industrial temperatures. If humans take action to hit a 1.5°C target, it means we are committed to keeping the human-caused global temperature rise to 1.5°C. Similarly for a 2°C target.

The lower the target, the smaller the climate change. The smaller the climate change, the better. But is it worth the effort to set lower targets? I mean, if 2°C is good enough, why take the trouble to keep temperatures within 1.5°C?

Fortunately, a new paper just out in the Philosophical Transactions of the Royal Society A asks this question. Specifically, they ask “How much larger are the impacts at 2°C compared to 1.5°C?” A follow-on question asked by the authors relates to what conditions occur at a particular level of warming, such as 2°C. This is a really important question because policymakers need to know what it will take to adapt to a 1.5°C world or a 2°C world.

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6 comments


Study: wind and solar can power most of the United States

Posted on 26 March 2018 by John Abraham &

In order to combat climate change, we need to rapidly move from fossil fuel energy to clean, renewable energy. The two energy sources I am most interested in are wind and solar power; however, there are other sources that have great potential.

Some people doubt how much wind and solar can supply to a country’s electricity grid. This is a particularly challenging question to answer in part because both solar power and wind power fluctuate in both space and time. We all know solar panels work well during the day, when the sun shines – they don’t work so well at night. And wind turbines only send electrons when the wind is blowing. 

Fortunately, these two sources of energy fluctuate in ways that complement each other. For instance, solar power generation is highest in the summer and lowest in the winter. Wind power is greatest in the spring and fall. Wind turbines work at night when solar panels are dormant. So, can these complementing variations help balance out the power that the two technologies can provide? 

This question was addressed in a very recent paper published in the journal Energy and Environmental Science. The author list included Dr. Ken Caldeira, who is extremely well known for his years of work in environmental science and energy.

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40 comments


Biofuels can help solve climate change, especially with a carbon tax

Posted on 14 March 2018 by John Abraham &

Facing the reality of human-caused warming, we now look for ways to reduce the problem so that future generations will not inherit a disaster. So, what can we do now to help the future?

The easiest answer is to use energy more wisely and quit wasting our precious resources. Second, we can increase our use of clean energy, particularly wind and solar power. These are great starts but we will still need some liquid fuels and for those, we can make decisions about the best fuels for the environment. There has been extensive conversation recently about biofuels and how they may help solve the climate problem.

The term “biofuels” has many meanings, but basically they are grown fuels (like corn ethanol) that we can use instead of fossil fuels (like petroleum). While biofuels can be any fuel produced from plant material, historically they have been produced from food crops such as corn and soy. But, new technologies are enabling biofuel production from non-edible gases, wood, and other plant waste material.

The beauty of biofuels is that they suck carbon dioxide out of the air as they grow. When we burn them in our automobiles, we release carbon dioxide, but it is the same carbon that the plants absorbed while growing. Just on that basis, biofuels appear to be zero net emitters.

But this view is too simplistic. It takes energy to grow biofuels; it takes fertilizer, tractors, transportation, and energy to convert the plants to liquid fuels. Planting and growing these crops can also change how much carbon is stored in the soil. And using existing food crops or arable land for biofuel production might lead to deforestation if farms are expanded elsewhere to make up for lost food production.

So, if you want to accurately assess the impact of biofuels, you need to look at what’s called a “life cycle analysis,” which basically means the effort it takes to grow the crops, harvest them, convert them to fuel, transport them to distribution sites, and combust them. 

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Scientists have detected an acceleration in sea level rise

Posted on 27 February 2018 by John Abraham &

As humans emit heat-trapping gases like carbon dioxide, the planet warms, and over time consequences become more apparent. Some of the consequences we are familiar with – for instance, rising temperatures, melting ice, and rising sea levels. Scientists certainly want to know how much the Earth has changed, but we also want to know how fast the changes will be in the future to know what the next generations will experience.

One of the classic projections into the future is for sea level rise. It is expected that by the year 2100, the ocean levels will rise a few feet by the end of the century. This matters a lot because globally, 150 million people live within three feet of current ocean levels. We have built our modern infrastructure based on current ocean levels. What happens to peoples’ homes and infrastructure when the waters rise?

But projecting ocean levels into the future is not simple; we need good data that extends back decades to understand how fast the climate is changing. The classic way to measure ocean levels is by using tide gauges. These are placed just offshore, around the globe to get a sense of how the ocean levels are changing. The problem with tide gauges is they only measure water levels at their location, and their locations are always near shore. 

In order to get a better sense of how oceans are changing everywhere, a complementary technology called satellite altimetry is used. Basically, the satellites shoot a radar beam from space to the ocean surface and watch for the reflection of the beam back to space. From this beam, the satellite can calculate the height of the water. Satellites can emit beams continuously as the satellite passes over open oceans, and can gather data far from shorelines. In doing so, they provide the equivalent of a global network of nearly half a million tide gauges, providing sea surface height information every 10 days for over 25 years.

Just recently, in the Proceedings of the National Academy of Sciences, a paper has been published that collects all the available satellite altimetry data and asks whether the sea level rise is accelerating. The authors of the paper are a well-respected team and include Dr. Steven Nerem from the Cooperative Institute for Research in Environmental Sciences (CIRES) and Dr. John Fasullo, from the National Center for Atmospheric Research. 

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Pollen data shows humans reversed natural global cooling

Posted on 19 February 2018 by John Abraham &

In order to understand today’s global warming, we need to understand how Earth’s temperatures varied in the past. How does the rapid warming we see now compare with past natural climate changes? Also, how long have humans been having an impact on the climate? These are some questions that can be answered through paleoclimate studies. Paleoclimate research uses natural measurements of the Earth’s temperature. Clever scientists are able to estimate how warm or cold the Earth was far back in time, way before we had thermometers. 

Readers of this column are probably familiar with some of these paleoclimate techniques that may use ice cores or tree rings to infer temperature variations. A different method that uses plant distribution was a technique used in a very recent study published in Nature. That technique used pollen distribution to get an understanding of where plant species thrived in the past. Those distributions gave them insights about the temperatures. On the surface, it’s pretty straightforward. Tropical plants differ in major ways from plants that live in, say, the tundra. In fact, plants that thrive where I live (Northern USA) differ from plants that populate landscapes further south.

The authors used the pollen of various plants to help determine where they thrived in the deep past. I communicated with Dr. Bryan Shuman, from the University of Wyoming and I asked him why they used pollen. He responded:

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Climate change is increasing flood risks in Europe

Posted on 8 February 2018 by John Abraham &

As humans continue to emit greenhouse gases like carbon dioxide, the world continues to warm. We see that warming everywhere – in the atmosphere, in the oceans, with rising sea levels, and melting ice. But while we know conclusively that humans are causing the warming, an equally important question is, “so what?” Really, we want to know the consequences of warming so that we can make informed decisions about what to do about it. We really have only three choices: mitigate, adapt, or ignore and suffer the consequences.

A very new study was just published that helps answer this question of “so what?” The research was conducted by lead author Lorenzo Alfieri (European Commission – Joint Research Centre, Italy), Richard Betts (University of Exeter and Met Office, UK), and their colleagues.

In the study, the authors used what are called Impact Models to assess the risks of large-scale flooding. They focused their attention on Europe partly because there is a lot of hydrological information there, flood reporting is easily available, and predictions of future climate there are plentiful. The authors compared estimates of flood risk in Europe from three recent case studies; their comparison incorporated changes to future climate, expected damage, and population that will be affected in the flooding zones.

I think of this as a three-part study. First, the authors obtained climate projections for Europe using state-of-the-art climate models. Next, they input the future climate into calculations that quantify flood risk and the impacts. Last, they compared the results that they obtained from their different damage calculation algorithms. The authors looked for areas where the calculations agreed or disagreed with each other. At the end of the day, they wanted to answer two key questions:

1. Is it possible to identify trends that are consistent among the models to help Europe prepare for changes to flood risk?

2. Are there differences in the models and if so, why?

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In 2017, the oceans were by far the hottest ever recorded

Posted on 26 January 2018 by John Abraham &

Among scientists who work on climate change, perhaps the most anticipated information each year is how much the Earth has warmed. That information can only come from the oceans, because almost all heat is stored there. If you want to understand global warming, you need to first understand ocean warming.

This isn’t to say other measurements are not also important. For instance, measurements of the air temperature just above the Earth are really important. We live in this air; it affects us directly. A great commentary on 2017 air temperatures is provided by my colleague Dana Nuccitelli. Another measurement that is important is sea level rise; so too is ocean acidification. We could go on and on identifying the markers of climate change. But in terms of understanding how fast the Earth is warming, the key is the oceans. 

This important ocean information was just released today by a world-class team of researchers from China. The researchers (Lijing Cheng and Jiang Zhu) found that the upper 2000 meters (more than 6000 feet) of ocean waters were far warmer in 2017 than the previous hottest year. We measure heat energy in Joules. It turns out that 2017 was a record-breaking year, 1.51 × 1022 Joules hotter than any other year. For comparison, the annual electrical generation in China is 600 times smaller than the heat increase in the ocean.

The authors provide a long history of ocean heat, going back to the late 1950s. By then there were enough ocean temperature sensors to get an accurate assessment of the oceans’ warmth. Their results are shown in the figure below. This graph shows ocean heat as an “anomaly,” which means a change from their baseline of 1981–2010. Columns in blue are cooler than the 1981-2010 period, while columns in red are warmer than that period. The best way to interpret this graph is to notice the steady rise in ocean heat over this long time period.

OHC

Ocean heat content change since 1958. Illustration: Cheng and Zhu (2018), Advances in Atmospheric Sciences

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Study finds that global warming exacerbates refugee crises

Posted on 15 January 2018 by John Abraham &

The refugee crisis – particularly in the Mediterranean area – has received large amounts of new attention in the past few years, with people fleeing from Syria and entering the European Union emblematic of the problem. There has been some research connecting this refugee problem with changes to the climate. In particular, the years preceding the Syrian refugee crisis were characterized by a severe drought that reduced farm output and led to economic and social strife there.

Separating out the influences of climate change from general social instability may be impossible, because they are intimately linked. But we do know that climate change can cause social and economic instability. We also know that these instabilities can boil over into larger problems that lead to mass exodus. The problem isn’t knowing the connection between climate and refugees exists – rather the problem is quantifying it. 

All of this is important because we want to be able to plan for the “now” as well as the “tomorrow.” If we are already seeing climate-related migrations, can you imagine what’s in store in the next few decades as temperatures and extreme weather continue to increase?

A very recent publication appearing in the journal Science investigates this complex subject. The paper, Asylum Applications Respond to Temperature Fluctuations, was published by Anouch Missirian and Wolfram Schlenker from Columbia University. It focused not just on Syria and the Mediterranean area, but expanded their study to be worldwide.

The researchers identified 103 countries that contributed to asylum applications to the European Union. Collectively, these nations submitted 350,000 applications to the EU per year. The authors combed the weather histories from these 103 source sites and explored how the weather varied in the 2000–2014 time period. 

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US government climate report looks at how the oceans are buffering climate change

Posted on 26 December 2017 by John Abraham &

In the recently released US Global Change Research Program Report, one of the chapters I was most interested in was about the changes we’ve observed in the world’s oceans. The oceans are really the key to the climate change issue, whether that be in quantifying how fast it’s happening or how much will happen in the future. As humans emit greenhouse gases (particularly carbon dioxide), we see some major changes that cannot be explained naturally.

The oceans are important because they act as a buffer; that is, they absorb much of the effects of greenhouse gases. In fact, the oceans absorb a lot of human carbon pollution. This is a big help for us because without the oceans, the climate would change much faster. 

But in a certain way, the oceans are hurting us too. Since the oceans absorb so much of our carbon pollution and the resulting heat (93% of the extra heat), they turn a short-term problem into a long-term problem. Just like a fly wheel can be used to store rotating energy in a machine, the oceans store heat energy and chemical energy that can later manifest itself. The oceans also impact our psychology. The pollution we emit today will have effects for many years (partly because of the oceans). We cannot just stop emitting pollution and think this problem will immediately go away. We have to plan ahead. And, importantly, we have to stop emitting before most of the effects are evident.

I like to think of the Earth’s climate like a heavy train. A train cannot stop quickly; the brakes have to be applied far ahead of an obstacle. The ocean is our “climate train.”

Okay with that, what did this new report show? There were four key findings the authors cited. First, as I mentioned, they report that the oceans are absorbing almost all the heat from greenhouse gases. Over the past six decades, the amount of heat at all levels of the ocean has increased. This heating will continue into the future with approximately 5°F warming by the year 2100. This may not sound like much, but it is really enormous heating for water. When oceans warm, sea levels rise (warming water expands). Warm water also evaporates much faster to the air so that the atmosphere becomes more humid, resulting in more heavy rainfalls and flooding.

The figure below shows the changes in ocean heat (OHC) measured in Joules (a unit of energy).

OCH

Ocean heat content data. Illustration: USGCRP report, originally from Cheng et al., 2017

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The US is penny wise and pound foolish on the climate

Posted on 13 December 2017 by John Abraham &

The United States is great in many respects. But we certainly aren’t perfect; we’ve made some pretty silly choices. One of the dumb choices politicians in the United States want to make is to defund climate science so we wont be able to prepare for increased disasters in the future. We can see how shortsighted this in when compared alongside with the costs of disasters.

Just think about the respective magnitudes. Estimates put the costs of the three big 2017 hurricanes (Harvey, Irma, and Maria) at approximately $200 billion. It is somewhat challenging to estimate the actual cost because not only is there rebuilding that must occur, but there are also lingering damages from loss of power, dislocation of people, and other long-lasting factors. Some reports estimate that the damage may end up being as high as $300 billion – a staggering amount.

It isn’t just hurricanes that cause damage. As I write this, terrible fires are devastating parts of California, damaging property and agricultural lands. This is on top of earlier fires elsewhere in the region, which followed closely on record droughts that had persisted in the preceding five years.

Earlier in the year the United States had other disasters that reached a billion dollars or more in damages (two floods, seven severe storms among others). Noaa provides an excellent summary.

NOAA

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US government report finds steady and persistent global warming

Posted on 6 December 2017 by John Abraham &

The US Global Change Research Program recently released a Climate Science Special Report. It is clearly written – an authoritative summary of the science, and easy to understand.

The first main chapter deals with changes to the climate and focuses much attention on global temperatures. When most people think of climate change, they think of the global temperature – specifically the temperature of the air a few meters above the Earth surface. There are other (better) ways to measure climate change such as heat absorbed by the oceans, melting ice, sea level rise, or others. But the iconic measurement most people think of are these air temperatures, shown in the top frame of the figure below.

warming indicators

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American leaders should read their official climate science report

Posted on 27 November 2017 by John Abraham &

The United States Global Change Research Program recently released a report on the science of climate change and its causes. The report is available for anyone to read; it was prepared by top scientists, and it gives an overview of the most up to date science. 

If you want to understand climate change and a single document that summarizes what we know, this is your chance. This report is complete, readily understandable, and accessible. It discusses what we know, how we know it, how confident we are, and how likely certain events are to happen if we continue on our business-as-usual path. 

To summarize, our Earth has warmed nearly 2°F (1°C) since the beginning of the 20th century. Today’s Earth is the warmest it has ever been in the history of modern civilization.

USGCRP

Global average surface temperatures over the past 1,700 years. Illustration: United States Global Change Research Program

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An Inconvenient Sequel – the science, history, and politics of climate change

Posted on 15 November 2017 by John Abraham &

Al Gore’s new movie ‘An Inconvenient Sequel’ is, in some ways, similar to his groundbreaking Inconvenient Truth project, but different in other ways. Those key differences are why I recommend you watch it.

This movie successfully accomplishes a number of interweaving tasks. First, it gives some of the science of climate change. Gore gets his science right. I remember his first movie, which I thought was more steeped in science and data than this one, so based on my recollection this new picture is somewhat abbreviated. That’s a good thing because the science is settled on climate change. That is, the science is settled that humans are causing current climatic changes and the science is settled that we are observing these changes throughout the natural world. 

Readers of this column who venture into the comments below will likely find people claiming, “science is never settled.” But the people making those comments are not scientists. They don’t work in this field every day, they don’t see the data, and they don’t know what they’re talking about.

The opening of the new film shows a sample of the misguided attacks on Al Gore, exclusively from conservatives in the United States. It was so clear to me, when watching and listening, that these attacks are the same ones that we climate scientists constantly have to endure. Most scientists have not been attacked as consistently or for such a long duration as Mr. Gore, but the types of attacks he has had to handle are close cousins to what my colleagues and I experience on a regular basis. 

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What do Jellyfish teach us about climate change?

Posted on 7 November 2017 by John Abraham &

What do Jellyfish teach us about climate change?

A lot. At least that’s what I learned after reading a very recent paper out in the journal Global Climate Change. The article, “Ocean acidification alters zooplankton communities and increases top-down pressure of a cubazoan predator,” was authored by an international team of scientists – the paper looks at impacts of climate change on life in the world’s oceans.

I recall attending a horse-pulling contest as a child. The announcer at the event said something strange that stuck with me all these years. He said that two horses pulling a load at the same time are more effective than if the two horses pulled separately and their loads were added. That is, something about two horses working together made them greater than the sum of their parts. This study is a lot like those horses.

To begin, ocean acidification refers to the changing pH of ocean waters. As humans emit more greenhouse gases (carbon dioxide in particular) into the atmosphere, the chemistry of the oceans change. The effect is that the creatures living in the oceans are experiencing an environmental change that is separate from changing temperatures due to global warming. Scientists want to know how these changes will affect creatures, in particular because the biodiversity in the oceans is so very important to us as humans.

There has been some reporting on studies of calcifying organisms and their susceptibility to changing chemistry in the oceans. For instance, echinoderms, molluscs, corals, and crustaceans have been studied in laboratories and in situ. The studies show that acidification reduces development and survival. Acidification can alter the way these creatures make and maintain their shells.

But the authors of this new study point out that there are many other non-calcifying organisms that may also be impacted by acidification. Even for these creatures, acidification has been shown to have deleterious effects that result in reduced survival, reduced reproductivity, and reduced size.

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What does a sexist Google engineer teach us about women in science?

Posted on 25 October 2017 by John Abraham &

What does a sexist Google engineer teach us about women in science?

Nothing. 

That’s the short answer, but it deserves some commentary. In early August, a young Google computer engineer made lots of news in the US when he penned a manifesto that many described as sexist and which led to his firing. The memo was written as a backlash against efforts to improve diversity in the workplace. However, the arguments articulated by the manifesto were rightly described as offensive by Google executives. 

The explosive part in the memo involved comments about how biological differences explain the paucity of women in technology and leadership fields. While there are certainly both physical and mental differences between men and women, the comments about both genders are, in my opinion, misguided and offensive.

This article is not going to focus much on the content of this so-called manifesto. It also won’t focus on the author of this document, except to question the basis for how a very young engineer has the experience, training, or education to make such broad-brush generalizations. I mean, has he for instance managed scores of male and female engineers and been able to assess their quality of work and intellectual capacity? I doubt it. Has he studied this in any detail or published on the topic? I doubt it.

I found this manifesto so ironic because I give a lot of thought to differences between male and female scientists. I am not an expert in the area, certainly not in evolutionary biology. But I am a Full Professor with many years of instructing both undergraduate and graduate students in engineering. I am often struck by how small the female population is in my discipline (perhaps 20%), yet it is higher in other technical fields (biology, mathematics, chemistry, etc.). I am also impressed by how well female students do in technical courses and degree programs. I note a statistically significant performance gap between male and female students in courses; females consistently outperform their male peers.

I also have had the fortune to be a consultant for many different engineering companies from industries such as biomedical, aerospace, manufacturing, clean energy and other fields. In my work, I notice that women team members easily hold their own with male co-workers. I also believe (but I have no evidence) that women think differently than men. 

In my anecdotal experience, women are able to consider problems from a wider range of perspectives. This perspective has real value to design teams, it encourages companies to pay more for female employees (yes, our female engineering graduates tend to make more than their male counterparts). Diverse teams make effective teams. That includes gender diversity. So, in my 15 or so years as a professor, and in my perhaps 50 consulting positions, I have lived an experience very different from the one this young Google engineer articulated.

With all that said, I thought this event provided an excellent opportunity to showcase some female scientists who are either world-known or becoming world-known in the field of climate science. So, here are some short bios of brilliant women climate scientists.

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CliFi – A new way to talk about climate change

Posted on 18 October 2017 by John Abraham &

Cli-Fi refers to “climate fiction;” it is a term coined by journalist Dan Bloom. These are fictional books that somehow or someway bring real climate change science to the reader. What is really interesting is that Cli-Fi books often present real science in a credible way. They become fun teaching tools. There are some really well known authors such as Paolo Bacigalupi and Margaret Atwood among others. A list of other candidate Cli-Fi novels was provided by Sarah Holding in the Guardian.

What makes a Cli-Fi novel good? Well in my opinion, it has to have some real science in it. And it has to get the science right. Second, it has to be fun to read. When done correctly, Cli-Fi can connect people to their world; it can help us understand what future climate may be like, or what current climate effects are.

As I write this, we are getting a steady stream of stories out of Puerto Rico the island was devastated by Hurricane Maria. It is hard to imagine the devastation, what life is like without electricity, food, or water. What is life like on an island of 3 million people, each fending for themselves, just trying to survive.

Another thing that is hard to imagine is the future. What will the world be like decades from now when Earth temperatures have continued to rise? What will agriculture be like? What will coastal communities be like? What will international relations and armed conflict be like?

It is also hard to imagine what living a subsistence agriculture life is like, today. What happens to lives and communities when the rains change, or don’t come at all? What would that world look like?

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Despite Trump, American companies are still investing in renewable energy

Posted on 11 October 2017 by John Abraham &

After the election of Donald Trump, many of us in the climate and energy fields were rightfully fearful. What would happen to international agreements to cut greenhouse gases? What would happen to funding for climate research? What would happen to the green energy revolution?

In most instances, Trump is worse than we could have imagined. But in one special area, Trump may not matter. That is in the growth of corporate purchasing of renewable energy. It turns out there are factors that even Trump cannot stop that make choosing renewable energy an easy decision for many companies.

New evidence about the unstoppable renewable energy wave recently came out in a report that was released by Apex Clean Energy and the GreenBiz Group. These groups surveyed corporations to determine their future plans on renewable energy installation and adoption. They wanted to know whether these plans had changed in the past few years and what motivated their decisions to implement renewable energy strategies. The outcome of this survey is available here for people who want to read the entire document.

The groups surveyed 153 major corporations (both public and private), whose combined revenue was in excess of $250 million. Among these companies, 84% are “actively pursuing or considering purchasing renewable energy over the next 5-10 years.” Surprisingly, they found that 43% of the corporations intend to be more aggressive in their pursuit of renewable energy in the next two years. 87% of those actively pursuing renewable energy purchases stated that the election of Trump had no impact on their decision. 

In fact, 11% were more inclined to purchase renewable energy. Most surprising to me was that of the 128 companies that are actively pursuing or considering purchase of renewable energy over the next two years, all but 1 responded that they were “positive about either continuing forward or becoming more aggressive in their attempts to pursue renewables.” 

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Climate and energy are becoming focal points in state political races

Posted on 28 September 2017 by John Abraham &

As soon as Donald Trump won the presidential election, people in the US and around the world knew it was terrible news for the environment. Not wanting to believe that he would try to follow through on our worst fears, we held out hope

Those hopes for a sane US federal government were misplaced. But they are replaced by a new hope – an emerging climate leadership at the state level and a continuation of economic forces that favor clean/renewable energy over dirty fossil fuels. In fact, it appears that some states are relishing the national and international leadership roles that they have undertaken. Support for sensible climate and energy policies is now a topic to run on in elections.

This change has manifested itself in American politics. One such plan stems from my home state, but it exemplifies work in other regions. I live in the state of Minnesota where we are gearing up for a gubernatorial election, which is where this plan comes from.

My state is well known as somewhat progressive, both socially and economically. The progressive policies resulted in a very strong 2007 renewable energy standard, which helped to reduce carbon pollution and create 15,000 jobs. 

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It takes just 4 years to detect human warming of the oceans

Posted on 20 September 2017 by John Abraham &

We’ve known for decades that the Earth is warming, but a key question is, how fast? Another key question is whether the warming is primarily caused by human activities. If we can more precisely measure the rate of warming and the natural component, it would be useful for decision makers, legislators, and others to help us adapt and cope. Indeed, added ocean heat content underlies the potential for dangerous intense hurricanes.

An answer to the “how fast?” question was partly answered in an Opinion piece just published on Eos.org, the daily online Earth and space science news site, by scientists from China, Europe and the United States. I was fortunate enough to be part of the research team.

To measure how fast the globe is warming, we focused on the extra heat that is being trapped in the climate. The key to measuring the extra heat is by comparing the incoming and outgoing energy – just like you watch your bank account, keeping track of income and expenses to tell whether your bank balance will increase or not.

Okay so how do we measure these incoming and outgoing flows? In our view, the best way is in the oceans. We know that the oceans absorb almost all of the excess heat – so, perhaps we can detect energy increases in ocean waters?

Measuring the oceans is challenging. They are vast and they are deep – measurements can be noisy. Detecting a long-term trend (a signal) within the noise can be a challenge. But this challenge is exactly what we focused on. We wanted to know how large the signal-to-noise ratio is for ocean heat measurements because this would tell us how many years of data are needed to detect warming. Can we detect global warming with one year of measurements? With a decade? Or do we need multiple decades of measurements to be sure the climate is changing?

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Study: mild floods are declining, but intense floods are on the rise

Posted on 8 September 2017 by John Abraham &

It is well known that humans are causing the Earth to warm. We also know that a warmer atmosphere has more water vapor. Just like the air is more humid when it is warm, and less humid when cold. The more humid air leads to more intense precipitation and potentially more flooding. But how much change we will see is an open scientific question.

This question is made complex by the fact that flooding isn’t just about rain. It reflects a dependence on evaporation, rain, the ability of land and water management to handle water surges, and other factors. Fortunately, a very recent study out of Science Advances has helped advance our understanding of the confluence of global warming, intense rain and flooding. 

The authors, Conrad Wasko and Ashish Sharma, from the University of New South Wales investigated various non-urban catchments. These are regions where precipitation drains to a common site. We know that in many places the rainfall is increasing. What these authors wanted to know was whether there was a coincident increase in floods found in these various catchments.

This study isn’t as simple as it might sound. The authors had to make choices about which rainfall event and which temperature peak corresponded to each other and to a potential water flow peak. According to the paper, “precipitation events were identified where the precipitation was separated by five days of zero rainfall.” That is, it had to be dry ahead of time. Streamflow and flooding events were selected as peaks separated by more than seven days. The authors then picked the largest peak from the precipitation and the streamflow observations and matched them to a coincident temperature measurement. 

The tough part is that there can be a delay in temperatures and precipitation. Furthermore, there can be a physical distance between the source of the storm and the location of precipitation. Finally, many times we see flooding without the required five-day dry period. So admittedly this study has real limitations. On the other hand, the authors had to make some choices of selection and these are as good as any others. And, they compensated for these limitations by using extensive rainfall, temperature and streamflow data, data that represented the entire world and allows confident conclusions to be drawn.

What they found was that in most cases there is no direct link. That is, higher temperatures does not generally cause an increase in water flow or flood risk. 

So this begs the question, why not?

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The Trump administration wants to bail out failed contrarian climate scientists

Posted on 31 August 2017 by John Abraham &

Climate contrarians, like Trump’s EPA administrator Scott Pruitt and Energy Secretary Rick Perry, don’t understand how scientific research works. They are basically asking for a government handout to scientists to do what scientists are should already be doing. They are also requesting handouts for scientists who have been less successful in research and publications – a move antithetical to the survival of the fitness approach that has formed the scientific community for decades.

The helping handout would be through a proposed exercise called a “red team/blue team” effort. It is a proposal that would reportedly find groups of scientists on both “sides” of the climate issue (whatever that means), and have them try to poke holes in each others’ positions. I will explain why this is a handout but first let’s talk about the plan and how it interferes with the scientific process.

I say that Pruitt and Perry don’t understand how science works because we are already doing “red team/blue team” exercises everyday in our normal line of business. Science works by challenging each other and our ideas. If we think that a colleague has made an error, we tend to be merciless and tenacious to correct the errors. This is part of the premise of the concept of peer review – where we send studies and manuscripts to journals to have other experts objectively review them for errors.

So back to the basic premise of a red team/blue team exercise – basically the “red team” would critique some conclusion of a “blue team.” The blue team would be able to respond, and there would be this back and forth exchange. On its face it sounds pretty straightforward even though scientists are already doing that in the scientific literature. But how would this work in practice? 

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New study finds that climate change costs will hit Trump country hardest

Posted on 24 August 2017 by John Abraham &

Humans are causing Earth’s climate to change. We know that. We’ve known it for decades. Okay so what? The follow-up questions should be directed to what the effects of warming will be. What will the costs be to society, to the natural biosystem, and to human lives? Let’s be honest, if the consequences of warming are not large, then who cares? But, if the consequences are severe, then we should take action now to reduce the warming. This really comes down to costs and benefits. Are the benefits of reducing emissions greater or less than the costs? 

But there is a nuance to the answer. The costs are not uniformly distributed. Some regions will suffer more and other regions will suffer less. In fact, some regions will actually benefit in a warming climate. We understand that the world is interconnected and costs will inevitably be shared to some extent. But it is clear we won’t all suffer the same. 

It is also clear that the natural biosystems won’t suffer the same. Some areas are more susceptible to climate change, others less so. Coastal areas and tropical areas are great examples. We know that sea level rise and ocean acidification will impact coastal regions much more than where I live (Minnesota, USA). But tropical zones that experience a very small climate variation throughout the year (there is no winter, for instance, in the tropics) have biosystems that have evolved to survive in very tight climate ranges. The plants and animals just are not used to systematic changes to the climate.

In my opinion, the most interesting research deals with answering just these questions. 

Fortunately, a really important paper just came out in Science titled Estimating Economic Damage from Climate Change in the United States. Granted, this paper focused on the United States, but the analysis method and lessons can be applied elsewhere.

So what did they find? First, even in a single country like the United States, the losses will be very uneven. In general, the more southern states will suffer most. In the figure below, counties are colored by economic consequences from climate change under a business as usual scenario. The time period associated with the image is 2080–2099. Yellow, orange and red colors correspond to climate costs. Green colors are areas where climate change benefits will be seen.

costs map

Local economic costs/benefits from climate change under business as usual scenario by the years 2080–2099. Illustration: Hsiang et al. (2017), Science.

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Yale Climate Connections: America's beacon of climate science awareness

Posted on 14 August 2017 by John Abraham &

This is an unabashed endorsement of an important group. I have no affiliation with them or conflict of interest. They are great, period.

The ability to convey complex climate science to a wide-ranging audience is a golden attribute, something very few can achieve. This characteristic makes the Yale Climate Connections group unique.

The Yale Climate Connections effort comprises several interrelated efforts whose end result is captivating science education for the rest of us.

What is most exciting to me are their daily radio spots that focus on a current issue of climate change. The Yale group includes a team of editors, radio producers, and freelance reporters nationwide to record and post short (90-second) spots that are both interesting and informative. 

From someone who works in climate communication, I am surprised that a group can have this high of a throughput. It means your reporters have to be identifying relevant topics, finding experts to interview, learning enough to ask informed questions, and then perform audio edits. And this happens five days a week. The breadth and width of the topics can be seen at the group’s website. The radio spots are currently carried on almost 350 radio stations across North America and are hosted by Dr Anthony Leiserowitz, well known for his research on public opinions related to climate change, the “Six Americas.”

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Fossil fuel subsidies are a staggering $5 tn per year

Posted on 7 August 2017 by John Abraham &

Fossil fuels have two major problems that paint a dim picture for their future energy dominance. These problems are inter-related but still should be discussed separately. First, they cause climate change. We know that, we’ve known it for decades, and we know that continued use of fossil fuels will cause enormous worldwide economic and social consequences.

Second, fossil fuels are expensive. Much of their costs are hidden, however, as subsidies. If people knew how large their subsidies were, there would be a backlash against them from so-called financial conservatives.

A study was just published in the journal World Development that quantifies the amount of subsidies directed toward fossil fuels globally, and the results are shocking. The authors work at the IMF and are well-skilled to quantify the subsidies discussed in the paper.

Let’s give the final numbers and then back up to dig into the details. The subsidies were $4.9 tn in 2013 and they rose to $5.3 tn just two years later. According to the authors, these subsidies are important because first, they promote fossil fuel use which damages the environment. Second, these are fiscally costly. Third, the subsidies discourage investments in energy efficiency and renewable energy that compete with the subsidized fossil fuels. Finally, subsidies are very inefficient means to support low-income households.

With these truths made plain, why haven’t subsidies been eliminated? The answer to that is a bit complicated. Part of the answer to this question is that people do not fully appreciate the costs of fossil fuels to the rest of us. Often we think of them as all gain with no pain.

So what is a subsidy anyway? Well, that too isn’t black and white. Typically, people on the street think of a subsidy as a direct financial cost that result in consumers paying a price that is below the opportunity cost of the product (fossil fuel in this case). However, as pointed out by the authors, a more correct view of the costs would encompass:

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Study finds human influence in the Amazon's third 1-in-100 year drought since 2005

Posted on 3 August 2017 by John Abraham &

If you are like me, you picture the Amazon region as an ever lush, wet, tropical region filled with numerous plant and animal species. Who would imagine the Amazon experiencing drought? I mean sure, if we think of drought as “less water than usual,” then any place could have a drought. But what I tend to envision with respect to drought is truly dry.

People who work in this field have a more advanced understanding than I do about drought, how and why it occurs, its frequency and severity, and the impact on natural and human worlds. This recognition brings us to a very interesting paper recently published in Scientific Reports, entitled Unprecedented drought over tropical South America in 2016: significantly under-predicted by tropical SST[sea surface temperature]. So, what did this paper show? 

Well, the Amazon region does encounter periodic droughts. There was one in 2005, another in 2010, both of which were 100-year events, and the most recent one in 2015-2016. The authors of this study, Amir Erfanian, Guiling Wang, and Lori Fomenko, all from the University of Connecticut, measured drought in three ways. They quantified the precipitation deficits and water storage on the ground. They also used two different vegetation measures of drought. The results showed that the most recent drought was unprecedented in severity. The video below shows a brief visual overview of the findings of this paper:

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A profile of award-winning climate scientist Kevin Trenberth

Posted on 27 July 2017 by John Abraham &

The American Geophysical Union - the pre-eminent organization of Earth scientists - presents annual awards to celebrate the achievements of scientists. The awards, which are often named after famous historical scientists, reflect the contributions to science in the area of the award namesake. With the 2017 award winners just announced, it’s appropriate to showcase one of the winners here. 

The 2017 winner of the Roger Revelle medal is Dr. Kevin E. Trenberth. One of the most well-known scientists in the world, he is certainly the person most knowledgeable about climate change that I know.

The Roger Revelle award is given to an honoree who has made outstanding contributions to the understanding of the atmosphere and its interactions with other parts of the climate system. Named after Roger Revelle, who was critical in bringing the idea of human-caused climate change to the scientific community, it is amongst the highest honors. Revelle wrote regarding increasing carbon dioxide in the atmosphere in 1957:

human beings are now carrying out a large scale geophysical experiment

Certainly the other scientists nominated were of incredible quality. Why was Kevin granted the award? I cannot answer this for certain because I was not on the committee, but it’s possible that he won strictly because of his scientific contributions.

Dr. Trenberth is a leading voice in the concept of Earth Energy Imbalance (which is really the rate of global warming). He also pioneered research related to the interactions of the atmosphere with the oceans, particularly the El Niño/La Niña cycle. He has worked on advancements to climate models and to experimental observations of climate. Another major area of contribution is the changes in precipitation with climate change, and especially the frequency and intensity of extremes. He has also changed the approaches to attribution of human-caused climate change.

But perhaps Dr. Trenberth won the award because of the sheer volume and impact of his scholarship. He is closing in on 70,000 citations to his work. This puts him near the top of the list worldwide for impact.

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Surrendering to fear brought us climate change denial and President Trump

Posted on 17 July 2017 by John Abraham &

This story picks up where an earlier post left off a few weeks ago. Then, I discussed some of the political realities associated with inaction on climate change. In that post, I said I would revisit the question of why so many people deny the evidence of a changing climate. Now is the time for that discussion.

What continually befuddles people who work on climate change is the vehement and indefensible denial of evidence by a small segment of the population. I give many public talks on climate change, including radio and television interviews and public lectures. Nearly every event has a few people who, no matter what the evidence, stay in a state of denial. By listening to denialist arguments, I find they fall into a few broad categories. Some of them are just plain false. Examples in this category are ones like:

There was a halt to global warming starting 1998.

Humans are only responsible for a tiny fraction of the greenhouse gases in the atmosphere.

Scientists are colluding to create this fraud.

Others are not false but are completely irrelevant. For example:

Climate is always changing.

We didn’t have thermometers a million years ago to measure global temperatures.

Cities are hotter than their surroundings.

Why would people think things or repeat statements that are known to be false or irrelevant? I am convinced that for the vast majority of people, they are not intentionally being incorrect. Something must be forcing them to be wrong. What could that be? Why are people so willing to believe and repeat lies?

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Bad news for climate contrarians – 'the best data we have' just got hotter

Posted on 3 July 2017 by John Abraham &

A new paper just published in the Journal of Climate is a stunning setback for the darling of cherry-picking for contrarian scientists and elected officials. Let’s walk though this so we appreciate the impact. 

The vast majority of scientists know that the climate is changing, humans are the main reason, and there are going to be severe consequences. We have decades of measurements that prove our understanding of this process. There is simply no debate or dispute. 

Despite this, there are a shrinking number of contrarian scientists, elected officials, and industry representatives that have spent endless time trying to downplay the impact. They have variously argued that the climate isn’t changing, that the changes won’t be very much, or that there are no viable solutions to the problem. Much of their position relies upon finding evidence that the current observations of warming are not great. That is, the Earth is not warming as fast as predictions. 

To support this incorrect (and intellectually dishonest) position, contrarians have scoured the data for any evidence at all that suggests the Earth is not warming. They have skipped oceans (which account for 93% of the warming). They skip the Earth’s surface temperature, ignore ice loss, ignore sea level rise, and in fact ignore everything except some select regions of the atmosphere. Their fallback position is that since a part of the atmosphere seems not to be warming very fast, this means the Earth isn’t warming or that climate models cannot be trusted. I know I know, this sounds dumb, and it is. But it is their current argument. 

But let’s pretend we are contrarians and let’s ignore the entirety of the Earth system except for this very small part. Do they have a point? There has been a lot of dispute about exactly how fast these atmospheric temperatures have been rising. Measurements are best made by weather balloons or by satellites. The satellites are convenient because they orbit the Earth quickly and can gather lots of information that is quite uniform across the globe. But satellites have their problems. 

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New study confirms the oceans are warming rapidly

Posted on 26 June 2017 by John Abraham &

As humans put ever more heat-trapping gases into the atmosphere, the Earth heats up. These are the basics of global warming. But where does the heat go? How much extra heat is there? And how accurate are our measurements? These are questions that climate scientists ask. If we can answer these questions, it will better help us prepare for a future with a very different climate. It will also better help us predict what that future climate will be.

The most important measurement of global warming is in the oceans. In fact, “global warming” is really “ocean warming.” If you are going to measure the changing climate of the oceans, you need to have many sensors spread out across the globe that take measurements from the ocean surface to the very depths of the waters. Importantly, you need to have measurements that span decades so a long-term trend can be established. 

These difficulties are tackled by oceanographers, and a significant advancement was presented in a paper just published in the journal Climate Dynamics. That paper, which I was fortunate to be involved with, looked at three different ocean temperature measurements made by three different groups. We found that regardless of whose data was used or where the data was gathered, the oceans are warming.

OHC

Ocean heat content increase globally (top frame) and in four ocean basins (bottom frames). Illustration: Wang et al. (2017), Climate Dynamics

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The Larsen C ice shelf collapse hammers home the reality of climate change

Posted on 12 June 2017 by John Abraham &

Very soon, a large portion of an ice shelf in Antarctica will break off and collapse into the ocean. The name of the ice shelf is Larsen C; it is a major extension from of the West Antarctic ice sheet, and its health has implications for other ice in the region, and sea levels globally.

How do we know a portion is going to collapse? Well, scientists have been watching a major rift (crack) that has grown in the past few years, carving out a section of floating ice nearly the size of Delaware. The speed of the crack has increased dramatically in the past few months, and it is nearly cracked through.

Larsen crack

Crack in Larsen C ice shelf. Photograph: Ted Scambos, NSIDC

Project Midas provides frequent updates on the Larsen C shelf. You can read a summary there, which reports:

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The day after withdrawing from Paris, Trump declared a flooding disaster in Missouri

Posted on 6 June 2017 by John Abraham &

I was debating this article. Should I write about the news that just occurred, or the news that will occur soon? I chose the past event – flooding in Missouri, USA. I will save a soon-to-collapse portion of the Larsen C Ice Shelf in Antarctica for my next article.

It’s sad, but true, that there are mounting ironies around Trump’s scientific ignorance on climate change and his ditching of the Paris Accord to reduce global warming. Scientists know the Earth is warming and that humans are the cause. One consequence of the warming is that weather is becoming more extreme. This means we are getting more extreme storms, including rain and floods. As our nation and the world suffers from the extreme weather, we can reflect on how things could have been different had our politicians heeded the warnings.

While President Trump’s pulling from the Paris treaty was worldwide news, what was not covered as well was his declaration the very next day that the state of Missouri is a disaster area because of flooding.

Why is flooding a symptom of warming? As air warms, it holds more moisture - it’s more humid. As the Earth warms, it means that the atmosphere holds more moisture year round. That moisture falls during storms as rain. What’s interesting is that the result is more of the most severe rains. That is, when it rains, it’s raining harder. Consequently, more flooding occurs. And we are seeing that across our nation. If you look at the trends in the most severe downpours, they are increasing – everywhere.

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Reflections on the politics of climate change

Posted on 2 June 2017 by John Abraham &

The science of climate change is clear. Scientists know that the Earth is warming and that humans are the reason. We also know that the Earth will continue to warm in the future; however, we can do something about it. We can dramatically change the trajectory.

If the science is so clear, why are there still so many people that don’t accept it? Why are there so many people who try to deny the evidence? Well, the why is something I will try handling in my next post. Here, I want to describe where things are, as I see them. Mind you, this is only my perspective, living in the USA, working on climate science and climate communication on a daily basis.

For various reasons, acceptance of climate science breaks down along ideological lines. First, a majority of people in every state in the US believes, for instance, that the Paris Accord is a good thing, that the USA should participate. It turns out, however, that there is higher acceptance of climate science and acceptance of the importance of action on the coasts (California, Oregon, Washington, New York, etc.). 

There are exceptions to this rule but I am generalizing. It also turns out that the more liberal your politics are, the more likely you are to accept the science and the solutions. With respect to politics, the results are stunning. Vast majorities of Democratic and independent voters are supportive. Interestingly, small majorities of even conservative Republicans are supportive.

There are other correlations.

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Global climate projections help civil engineers plan

Posted on 25 May 2017 by John Abraham &

People who work on building infrastructure understand the risks of climate change. As the Earth warms, new stresses are applied to our buildings, bridges, roads, houses, and other structures. Some of the obvious threats to infrastructure are from extreme weather including heat waves, storms, and intense rainfalls. There are some other less obvious threats, and many of the threats vary by location.

Regardless, the planning for infrastructure relies upon a reasonable estimation of future climate changes. To help quantify such an estimate for the civil engineering community, a recent paper was published by the Institution of Civil Engineering Journal of Forensic Engineering (I was fortunate to be a coauthor). The article was prepared with the collaboration of Dr. Michael Mann from Penn State University and Dr. Lijing Cheng from the Chinese Institute of Atmospheric Physics

The paper in question does not uncover new facts. We didn’t discover past warming that wasn’t known. We didn’t create new predictions that were previously uncreated. Rather, we assembled available information to provide a solid basis that can be used for future plans involving infrastructure.

The first thing we established was the long-term trend in the global temperature. While there are many groups around the world that collect global temperatures, two of the best known groups are NASA and NOAA. As shown in the data below, which I downloaded and graphed for the paper, temperatures have risen by about 1.4°C (approximately 2.5°F) from their low point circa 1900. Since scientists constantly argue against cherry picking; we used an average temperature over the 1880–1930 time period. Relative to that time, temperatures have risen about 1.2°C (1.8°F)

Abraham Fig 1

Global temperature anomalies since 1880. Illustration: Abraham et al., 2017, J. Forensics Engineering

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Study: inspiring action on climate change is more complex than you might think

Posted on 19 May 2017 by John Abraham &

We know humans are causing climate change. That is a fact that has been known for well over 100 years. We also know that there will be significant social and economic costs from the effects. In fact, the effects are already appearing in the form of more extreme weather, rising sea levels, ocean acidification, and so on.

So why haven’t humans done much about the problem? Answering that question may be more challenging than the basic science of a changing climate. Fortunately, a new review just out in Science helps us with this question. Lead author, Dr. Elise Amel, a colleague of mine, completed the review with colleagues Drs. Christie ManningBritain Scott, and Susan Koger. Rather than focusing solely on the problems with communicating the science of climate change, this work takes a wider view on the hurdles that get in the way of meaningful action.

The review points out that since the 1970s, extensive efforts to educate people have not lead to significant shifts in behavior. They also acknowledge that using fear or guilt has not been effective in getting people to act. So, what can help? 

Well, first we must understand that it is not just internal forces (emotions, beliefs, attitudes, etc.) that affect human behavior, but external influences as well. External factors, like social networks, societal roles, cultural worldviews, habits, infrastructure, investments, etc, are often severely underestimated in the extent to which they steer behavior. One fault of prior messaging is an almost exclusive focus of the first (internal) set of factors and a near-complete neglect of the latter (externals). The authors write:

Change is hard. Human beings are reticent to change their behavior even under the most compelling of circumstances, and environmental dangers do not tend to arouse the kind of urgency that motivates individuals to act. Mass transformation of unsustainable systems will be even more difficult than shifting individual behaviors, for unlike ants and bees, humans are not well equipped to coordinate behavior for common benefit.

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More errors identified in contrarian climate scientists' temperature estimates

Posted on 11 May 2017 by John Abraham &

Human emission of heat-trapping gases is causing the Earth to warm. We’ve known that for many decades. In fact, there are no reputable scientists that dispute this fact. There are, however, a few scientists who don’t think the warming will be very much or that we should worry about it. These contrarians have been shown to be wrong over and over again, like in the movie Groundhog Day. And, a new study just out shows they may have another error. But, despite being wrong, they continue to claim Earth’s warming isn’t something to be concerned about.

Perhaps the darlings of the denialist community are two researchers out of Alabama (John Christy and Roy Spencer). They rose to public attention in the mid-1990s when they reportedly showed that the atmosphere was not warming and was actually cooling. It turns out they had made some pretty significant errors and when other researchers identified those errors, the new results showed a warming.

To provide perspective, we know the Earth is warming because we can measure it. Most of the heat (93%) goes into the oceans and we have sensors measuring ocean temperatures that show this. We also know about warming because we have thermometers and other sensors all over the planet measuring the temperature at the surface or in the first few meters of air at the surface. Those temperatures are rising too. We are also seeing ice melting and sea level rising around the planet. 

So, the evidence is clear. What Christy and Spencer focus on is the temperatures measured far above the Earth’s surface in the troposphere and the stratosphere. Generally, over the past few decades these two scientists have claimed the troposphere temperatures are not rising very rapidly. This argument has been picked up to deny the reality of human caused climate change – but it has been found to be wrong.

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Medical scientists report on the impact climate change is having on health

Posted on 5 May 2017 by John Abraham &

As a climate scientist, I spend time and energy studying how fast the Earth is warming and what is causing the warming. This knowledge helps us predict what the future will look like. But, what most people are interested in is, “how will it affect me?” 

Some impacts we are pretty clear about, like the impacts related to sea level rise, increased storms and heavy precipitation, and increased drought and heat waves – particularly the impacts these events have on the economy. But climate change will affect us personally as well (by personally, I mean our physical person). 

In fact, climate change is already affecting personal human health around the world. This subject was the focus of a summary report just published by the Medical Society Consortium. What I really liked about this report is that it breaks down some of the key impacts by region. Unfortunately, the report is limited in scope to the USA. However, the general conclusions and trends can be illuminating for people outside the USA as well.

What was also welcome is that this report was prepared by physicians (not climate scientists) of major medical societies and the conclusions are based on the best available and current information of both the climate and health fields.

So what did they find?

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New study: global warming keeps on keeping on

Posted on 27 April 2017 by John Abraham &

As humans continue to dump heat-trapping gases like carbon dioxide into the atmosphere, the Earth continues to warm. In fact, it has been warming for decades and we now routinely hit temperatures that are 1°C (about 2°F) above the temperatures from 100 years ago.

But despite what we may expect, temperatures across the globe don’t rise little by little each year in a straight line. Rather, temperature changes are a bit bumpy. They go up and they go down somewhat randomly as they increase. Think of a wiggly line superimposed on a straight rising line.

A great depiction of the behavior is seen from the NASA data, shown below. Each black mark is the Earth’s temperature for a given year. The red line is calculated from 5-year averages of the black data marks and is much smoother than the black line. As you move from left to right, you pass from the year 1880 to the most recent year (2016), which is shown in the very upper right corner.

Careful observation of the graph shows that the last three years (2014, 2015, and 2016) were all record-breakers. It makes you wonder, what the chances are that global warming has sped up?

GISS

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New study shows worrisome signs for Greenland ice

Posted on 14 April 2017 by John Abraham &

As humans put more heat-trapping gases into the atmosphere, like carbon dioxide, ice around the planet melts. This melting can be a problem, particularly if the melting ice starts its life on land. That’s because the melt water flows into the oceans, contributing to rising sea levels. Right now there are three main reasons that sea levels are rising. First, as ocean waters heat, they expand. Second, melting of ice in Antarctica flows into the ocean. Third, melting of ice on Greenland flows into the ocean. There is other melting, like mountain glaciers, but they are minor factors.

Okay, so how much is melting of Greenland contributing to sea level rise? Estimates are that about 270 gigatons of water per year are melting. The melting of an ice sheet like that atop Greenland can occur from the surface as air temperatures and sunlight warm the upper layer of ice. It can also occur from the edges as ice shelves collapse and fall into the oceans in large chunks.

Increase in surface melting from Greenland.

 Increase in surface melting from Greenland. Illustration: National Snow and Ice Data Center

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New study links carbon pollution to extreme weather

Posted on 7 April 2017 by John Abraham &

It was only a few weeks ago that I wrote about changes to extreme weather in a warming world. That prior article dealt with the increase of extreme precipitation events as the Earth warms. I termed the relationship a thermodynamic one; it was driven by local thermodynamic processes. But extreme weather can also occur because of large-scale changes to the atmosphere and oceans. This issue is the topic of another just-published paper that makes a convincing case for a whole new type of influence of humans on extreme weather. In a certain sense, this study confirms what was previously reported here and here. With the march of science, the tools, methods, and evidence get better each year.

Before getting into the study, a little background. The jet stream(s) are high-speed rivers of air that flow in the upper atmosphere. There’s more than one jet stream; they blow west to east and they mark the separation of zones of different temperatures. A good primer on jet streams is available here.

If you were to stand at the northern pole and travel southwards, you would experience a gradual increase in temperature. However, when you reached the first jet stream (the Polar Jet), temperatures would rapidly become warmer. That is, the Polar Jet separates two different temperature air regions. Typically, if you are north of the jet stream, you are in a colder zone whereas if you are south of the stream, it is warmer. Sometimes, the jet streams undulate as they encircle the planet and these undulations move. So, sometimes you happen to be in a position north and sometimes south of the stream, even though your location is fixed.

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Scientists understood the climate 150 years ago better than the EPA head today

Posted on 31 March 2017 by John Abraham &

The current head of the US Environmental Protection Agency Scott Pruitt does not believe or understand long-known principles of climate science and basic physics. Recently he claimed on CNBC that carbon dioxide is not a primary contributor to global warming:

I think that measuring with precision human activity on the climate is something very challenging to do, and there’s tremendous disagreement about the degree of impact. So, no, I would not agree that’s a primary contributor to the global warming that we see. But we don’t know that yet. We need to continue the debate and continue the review and the analysis.

There are two undeniable ironies in this statement. First, taken at face value it would suggest that we actually need to do more analysis – but the current administration is proposing draconian cuts in our climate science research budget. They are doing just the opposite of what he recommends.

The second irony is that scientists have known about the importance of carbon dioxide as a greenhouse gas for well over 100 years. There is no debate among any reputable scientists that carbon dioxide is the most important human emitted greenhouse gas. Furthermore, humans have increased the amount of carbon dioxide in the atmosphere by 43%. These are facts.

So, I wanted to revisit some of the first studies on carbon dioxide and its effect on the climate to put into perspective how backwards Pruitt is. One of the first works, and certainly a seminal study was completed in 1827 by Jean Baptiste Fourier. An excellent summary of the contributions of his work is provided here

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Global warming is increasing rainfall rates

Posted on 22 March 2017 by John Abraham &

he world is warming because humans are emitting heat-trapping greenhouse gases. We know this for certain; the science on this question is settled. Humans emit greenhouse gases, those gases should warm the planet, and we know the planet is warming. All of those statements are settled science.

Okay so what? Well, we would like to know what the implications are. Should we do something about it or not? How should we respond? How fast will changes occur? What are the costs of action compared to inaction? These are all areas of active research.

Part of answering these questions requires knowing how weather will change as the Earth warms. One weather phenomenon that directly affects humans is the pattern, amount, and intensity of rainfall and the availability of water. Water is essential wherever humans live, for agriculture, drinking, industry, etc. Too little water and drought increases risk of wild fires and can debilitate societies. Too much water and flooding can occur, washing away infrastructure and lives.

It’s a well-known scientific principle that warmer air holds more water vapor. In fact, the amount of moisture that can be held in air grows very rapidly as temperatures increase. So, it’s expected that in general, air will get moister as the Earth warms – provided there is a moisture source. This may cause more intense rainfalls and snow events, which lead to increased risk of flooding. 

But warmer air can also more quickly evaporate water from surfaces. This means that areas where it’s not precipitating dry out more quickly. In fact, it’s likely that some regions will experience both more drought and more flooding in the future (just not at the same time!). The dry spells are longer and with faster evaporation causing dryness in soils. But, when the rains fall, they come in heavy downpours potentially leading to more floods. The recent flooding in California – which followed a very intense and prolonged drought – provides a great example.

Okay so what have we observed? It turns out our expectations were correct. Observations reveal more intense rainfalls and flooding in some areas. But in other regions there’s more evaporation and drying with increased drought. Some areas experience both.

Some questions remain. When temperatures get too high, there’s no continued increase in intense rain events. In fact, heavy precipitation events decrease at the highest temperatures. There are some clear reasons for this but for brevity, regardless of where measurements are made on Earth, there appears to be an increase of precipitation with temperature up until a peak and thereafter, more warming coincides with decreased precipitation. 

A new clever study by Dr. Guiling Wang from the University of Connecticut and her colleagues has looked into this and they’ve made a surprising discovery. Their work was just published in Nature Climate Change. They report that the peak temperature (the temperature where maximum precipitation occurs) is not fixed in space or time. It is increasing in a warming world. 

The idea is shown in the sketch below. Details vary with location but, as the world warms, there is a shift from one curve to the next, from left to right. The result is a shift such that more intense precipitation occurs at higher temperatures in future, while the drop-off moves to even higher temperatures. 

rainfall diagram

An idealized example of increasing precipitation curves as the world warms for the Midwest. Illustration: John Abraham

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Just who are these 300 'scientists' telling Trump to burn the climate?

Posted on 27 February 2017 by John Abraham &

If you read my articles regularly, you may have noticed multiple times I have stated that the scientific argument is over; there are no longer any reputable scientists that deny the overwhelming human influence in our climate. An open letter published last week by the anti-environmentalists proves my point. 

If you read the headlines, it might have seemed impressive: “300 Scientists Tell Trump to Leave UN Climate Agreement.” Wow, 300 scientists. That’s a lot right? Actually, it’s a pitiful list.

First of all, hardly anyone on the list was a climate scientist; many were not even natural scientists. It is almost as though anyone with a college degree (and there are about 21 million enrolled in higher education programs just in the USA) was qualified to sign that letter.

Okay but what about the signers of the letter? Surely they are experts in the field? Not so much. It was very difficult to find the list of signers online however I was able to acquire it with some help. See for yourself - Google “300 scientists letter climate change” in the past week. You will see many stories in the press, but try finding the actual letter or the list of names. The version I obtained was dated February 23, 2017 which helps narrow your searching. In an era of Dr. Google, it is unbelievable that the letter itself was not made more available. 

Okay but let’s get to the central issue. These 300 scientists must be pretty good at climate science, right? Well let’s just go through the list, alphabetically. Here is a sampling (text copied verbatim from the version of the letter I obtained).

Example 1:

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OMG measurements of Greenland give us a glimpse of future sea rise

Posted on 24 February 2017 by John Abraham &

If you meet a group of climate scientists, and ask them how much sea levels will rise by say the year 2100, you will get a wide range of answers. But, those with most expertise in sea level rise will tell you perhaps 1 meter (a little over three feet). Then, they will immediately say, “but there is a lot of uncertainty on this estimate.” It doesn’t mean they aren’t certain there will be sea level rise – that is guaranteed as we add more heat in the oceans. Here, uncertainty means it could be a lot more or a little less. 

Why are scientists not certain about how much the sea level will rise? Because there are processes that are occurring that have the potential for causing huge sea level rise, but we’re uncertain about how fast they will occur. Specifically, two very large sheets of ice sit atop Greenland and Antarctica. If those sheets melt, sea levels will rise hundreds of feet.

Parts of the ice sheets are melting, but how much will melt and how fast will the melting occur? Are we talking decades? Centuries? Millennia? Scientists really want to know the answer to this question. Not only is it interesting scientifically, but it has huge impacts on coastal planning.

One reason the answer to this question is illusive is that melting of ice sheets can occur from above (warm air and sunlight) or from below (warm ocean waters). In many instances, it’s the melting from below that is most significant – but this melting from below is really hard to measure. 

With hope we will have a much clearer sense of ice sheet melting and sea level rise because of a new scientific endeavor that is part of a NASA project - Oceans Melting Greenland (OMG). This project has brought together some of the best oceanographers and ice experts in the world. The preliminary results are encouraging and are discussed in two recent publications here and here.

In the papers, the authors note that Greenland ice loss has increased substantially in recent decades. It now contributes approximately 1/3 to total sea level rise. The authors want to know whether this contribution will change over time and they recognize that underwater processes may be the most important to study. In fact, they note in their paper:

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Scientists study ocean absorption of human carbon pollution

Posted on 16 February 2017 by John Abraham &

As humans burn fossil fuels and release greenhouse gases, those gases enter the atmosphere where they cause increases in global temperatures and climate consequences such as more frequent and severe heat waves, droughts, changes to rainfall patterns, and rising seas. But for many years scientists have known that not all of the carbon dioxide we emit ends up in the atmosphere. About 40% actually gets absorbed in the ocean waters.

I like to use an analogy from everyday experience: the ocean is a little like a soda. When we shake soda, it fizzes. That fizz is the carbon dioxide coming out of the liquid (that is why sodas are called “carbonated beverages”). We’re doing the reverse process in the climate. Our carbon dioxide is actually going into the oceans. 

The process of absorption is not simple – the amount of carbon dioxide that the ocean can hold depends on the ocean temperatures. Colder waters can absorb more carbon; warmer waters can absorb less. So, a prevailing scientific view is that as the oceans warm, they will become less and less capable of taking up carbon dioxide. As a result, more of our carbon pollution will stay in the atmosphere, exacerbating global warming. But it’s clear that at least for now, the oceans are doing us a tremendous favor by absorbing large amounts of carbon pollution.

How much carbon dioxide is being absorbed by the oceans is an active area of research. In particular, scientists are closely watching the oceans to see if their ability to absorb is changing over time. Such a study is the topic of a very recent paper published in the journal Nature. The authors studied recent ocean carbon dioxide uptake and in particular the mystery of why it appears the oceans are actually becoming more absorbing.

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Mail on Sunday launches the first salvo in the latest war against climate scientists

Posted on 7 February 2017 by John Abraham &

In this new political era, climate scientists and their science are under attack. The attack is from multiple fronts, from threats to pull funding of the important instruments they use to measure climate change, to slashing their salaries and jobs. But there is a real fear of renewed personal attacks, and it appears those fears are now being realized. What the attackers do is identify and isolate scientists – a process termed the “Serengeti Strategy” by well-known and respected scientist Michael Mann who suffered these types of attacks for years.

The author of the recent attack piece, David Rose in the UK, has a history of denying the well-established science of climate change. He has a long history of making incorrect climate change statements. In the attack, Mr. Rose claims that scientists used misleading data in a recent (2015) paper that studied the rate of temperature change across the globe. He reportedly obtained information from someone who works at NOAA to imply that internal review procedures were not followed as the paper was prepared for publication. What Mr. Rose omitted however, is incredibly telling and he does a disservice to his readers.

First, he neglects to mention that the work from the 2015 paper authored by Dr. Thomas Karl and others at NOAA has already been independently verified by other researchers.

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A punchy climate book from a citizen scientist

Posted on 2 February 2017 by John Abraham & Rob Honeycutt

We know the climate is changing, the Earth is warming, and humans are the cause. As a scientist who studies this daily, I know the evidence is compelling and mutually reinforcing. In fact, the evidence is so compelling that it’s almost impossible to find scientists who disagree.

We also know that it’s possible to solve this problem using today’s technology. We don’t need to wait for fairy dust or cold fusion. Using energy more wisely, increasing renewable energy, modernizing nuclear power, and other actions are all things we can do right now to make the future better. 

But we also know that there are many groups and companies that are trying to stop meaningful action on climate change. Sure, many are fossil fuel companies that want to continue to sell their product. Others are ideological groups and people that for various reasons reject the compelling science. They cannot bring themselves to understand the facts because it conflicts with their belief system. These groups and people spread misinformation and purposely try to muddy the waters by creating a “fake news” environment of sorts.

For the rest of us who are interested in making this world better but not experts on climate change, it’s a real challenge to separate the science from the baloney. Not only do you have to know the science, but you may have to communicate it in a very concise situation. We scientists are trained to bloviate, not to persuade.

Fortunately, there is help. For anyone who wants easy to access, short elevator-speech responses to the most common questions and myths about climate change, a new resource is available. Interestingly, it was authored not by a climate scientist but by a citizen scientist. I’ve read the text and can vouch for its scientific accuracy.

The book is entitled Twenty-eight Climate Change Elevator Pitches written by Rob Honeycutt - a contributor to Skeptical Science. This book covers topics typically in 2-3 pages. Really short, really concise, always on point. Rob uses analogies to help describe climate science in ways that the rest of us can relate. He includes both basic science chapters as well as myth debunking. For instance, he relates geological climate change to a boxing match

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We may be closer than we thought to dangerous climate thresholds

Posted on 26 January 2017 by John Abraham &

We don’t want the Earth to warm more than 1.5–2°C (2.7-3.6°F) compared to the pre-industrial climate. These targets are not magical; they are expert judgements about what it takes to avoid some of the more serious effects of climate change. We know the seas will rise (they already are). We know droughts and flooding will get more severe (they already are). We know there will be more heat waves, more intense storms, and ocean acidification (all happening now). We cannot stop some of the changes. But if we keep climate change to these limits, we think we can avoid the worst effects. 

Where did these targets come from? Well, I mentioned that they are expert judgements but they are based on science. For instance, we can look into the deep past using ice cores, sediment records, and other tools to see how the past climate changed. We can also look into the future with computer models to predict how the future climate will evolve. Through these tools we can get a sense of how large the impact is if temperatures rise.

The obvious question is, where are we at? How much have temperatures risen since the pre-industrial time period? It might seem like that is a simple question. In fact, groups like NASA in the USA regularly provide temperature data as below. According to this image, the 2016 temperature increase has just hit 1°C (1.8°F). So, it would appear that we have some ways to go before hitting our target, right? 

Not so fast. Whenever you see an image like the one below, you should ask what years are the baseline. These graphs are termed “temperature anomaly plots.” They don’t show the actual temperature; rather they show the temperature difference between two time periods. It turns out the figure below is oriented so that it is relative to the time period 1951-1980. So when we say that 2016 had a temperature anomaly of 1°C, we really mean that it was 1°C warmer than the 1951-1980 time period.

GISTEMP

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Parts of United States are heating faster than globe as a whole

Posted on 17 January 2017 by John Abraham &

Global warming obviously refers to temperature increases across the entire globe. We know the Earth is warming, we know it is human-caused, we have a pretty good idea about how much the warming will be in the future and what some of the consequences are. In fact, when it comes to the Earth’s average climate, scientists have a pretty good understanding.

On the other hand, no one lives in the average climate. We live spread out north, west, east, and south. On islands, large continents, inland or in coastal regions. Many of us want to know what’s going to happen to the climate where we live. How will my life be affected in the future? 

This type of question is answered in a very recent study published by scientists from the University of Massachusetts at Amherst. The team, which includes Dr. Raymond Bradley and researcher Dr. Ambarish Karmalkar looked specifically at the Northeastern United States. They found that this area will warm much more rapidly than the globe as a whole. In fact, it will warm faster than any other United States region. The authors expect the Northeast US will warm 50% faster than the planet as a whole. They also find that the United States will reach a 2 degree Celsius warming 10–20 years before the globe as a whole.

So why does this matter? Well first, it matters because some of the effects people will experience are directly tied to the temperature increase in their region. For instance, we know that warmer air leads to more intense precipitation. In fact, we are already observing increases in very heavy rainfall across the United States (especially in the Northeast). Based on this new research, that trend will only get worse. It means that winters in this region will get warmer and wetter – more winter precipitation will likely occur as rain rather than snow. This affects the availability of water into the spring months. It also means that summers will have more intense heat waves which will lead to more severe droughts.

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New study confirms NOAA finding of faster global warming

Posted on 4 January 2017 by John Abraham &

A new study has shown that a 2015 NOAA paper finding that the Earth is warming more rapidly than previously thought was correct.

Once again, science is shown to work. The laborious process in which scientists check and recheck their work and subject their ideas to peer review has led to another success. An independent test of global warming data has confirmed a groundbreaking 2015 study that showed warming was faster than prior estimates.

Because of its inconvenient findings, the study’s lead author Thomas Karl was subjected to harassment by Lamar Smith (R-TX), chair of the House Science Committee, in an effort to impugn his credibility. But now Karl and his co-authors have been vindicated.

Let’s take a step back and discuss the science. Measuring the temperature of the Earth is hard. There are many locations to measure and many choices to make. Should we measure the temperature of the ground? Of the ocean waters? How deep in the water? If we measure air temperatures, what height should the measurements be taken? How many locations should we make measurements at? What happens if the instruments change over time or if the location changes? What happens if a city grows near a measurement location and the so-called urban heat-island effect grows? How do we estimate the temperatures in areas where no measurements exist?

These and many other questions make measuring global warming challenge. Different groups of scientists make different decisions so that depending on the institution, they will get a slightly different temperature result.

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Climate change in 2016: the good, the bad, and the ugly

Posted on 2 January 2017 by John Abraham &

This past year had so many stories involving human-caused climate change – it will be forever in our memories. Here is a summary of some of the high points, from my perspective. When I say “high points” I don’t necessarily mean good. Some of these high points are bad and some are downright ugly. Let’s do the good first.

The Good

The best news of all, in my opinion, is the continued cost reductions and huge installations of clean energy both in the US and around the word. Wind, solar, and other renewables have been on an incredible run of decreasing costs and creative financing, which has made them economically competitive with dirty fossil fuels. Improvements and expansion of grid-based power storage has also advanced. These storage abilities are needed to allow intermittent power sources (like wind and solar) to play an even larger role in delivering power to the grid. In the end, clean power will win out based on simple dollars and cents – regardless of the fact they will also help save the world.

On an international scale, the US, China, and other countries ratified the Paris climate agreement, which gives us a reasonable chance at avoiding the worst effects of climate change. In the lead up to that ratification, the US took major actions domestically to reduce its own emissions through steps like the Clean Power Plan

Emissions have been reduced in some countries like the US for a variety of reasons. First, very cheap natural gas is displacing dirtier coal-based power. Secondly, renewable energy sources like wind and solar are expanding, and people are using energy more wisely. All of this happened with a major reduction in energy costs in the US. This shows you can have clean energy that is also cheap.

In court, it was a good year. A rag-tag group of pro-bono climate scientists beat a bunch of high-paid contrarians in court. We showed that their science was nonsense and the smart judge gave a very harsh judgement to the funded deniers.

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Republicans and Democrats alike want more clean energy

Posted on 20 December 2016 by John Abraham &

It’s almost an accepted dogma that in the United States (and in several other countries), liberals are much more in favor of taking actions to curb climate change whereas conservatives block such actions. That’s certainly true within the halls of power. For instance, in the United States, it has become a litmus test for Republication candidates to deny humans are causing climate change, to try to claim that it isn’t important, in many cases to demonize the messengers (the scientists), and to work to halt climate science so we won’t know how bad the problem is.

Conventional wisdom – and in fact the seemingly obvious message from this past election – is that this denial is good politics. If you want to get elected as a conservative, you have got to be anti-science. 

But perhaps what we thought was so just isn’t. A fascinating study was just released by Yale and George Mason Universities that involved a national survey of American opinions. What this survey found was astonishing. Almost 70% of registered voters in the U.S. believe that their country should participate in international agreements to limit global warming. Only 1 in 8 registered voters believe the U.S. should not participate in such agreements. Similarly, 70% of respondents support limits on carbon dioxide, the most important human-emitted heat trapping gas. 

Moreover, they agree to limits even if that means electricity costs will increase (although they won’t). What this means is that 7 in 10 registered voters agree with President Obama’s signature climate accomplishment, the Clean Power Plan. When considered by party affiliation, the responses were 85% for Democrats, 62% for Independents, and 52% for Republicans. Yes, even among Republicans, whose elected officials systematically mock science, the majority of voters are in agreement about the importance of taking climate change seriously.

Amongst the respondents, more than 80% agreed that if a carbon tax is imposed, the revenues should be used to improve U.S. infrastructure, and large majorities support using the funds to help displaced fossil fuel workers or reducing the national debt.

A deeper dive into the results reveals that American voters are more knowledgeable about energy and the energy economy than is the president elect. They recognize the connection between the new clean energy economy and their own country’s economic vitality. 

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Oceanographers offer clues to Malaysian airlines crash

Posted on 14 December 2016 by John Abraham &

It isn’t that there is no evidence of the crash. In July of last year, a portion of a wing was found near Madagascar and Reunion Island in the Indian Ocean. Since then, other debris has been found in the Western Indian Ocean.

Using the location of where the wing debris were found, oceanographers from University of Santiago de Compostela (Spain), the United States National Oceanographic and Atmospheric Administration (NOAA), the University of Miami, University of Hawaii, and the Commonwealth Science Industrial and Research Organization (CSIRO) in Australia have a lead. Their hypothesis is published in the Journal of Operational Oceanography and can be found here.

The authors used two sets of data to help track the possible paths of the debris. First, they took advantage of observations from NOAA’s Global Drifter Array. These drifters have a surface float and an anchor or drogue that extend to 15m deep, and a suite of sensors that communicate via satellite their location and parameters like ocean currents, surface ocean temperature, pressure, wind, and salinity. In the Indian Ocean alone, there are approximately 400 of these drifters at any time, providing continuous ocean measurement information. At some point the drifters loose their drogue and these are the ones used in this study as they better simulate debris dynamics.

Deployment of a drifter.
 Deployment of a drifter. Photograph: NOAA

The authors tracked drifters that were released or that traveled near the search area in the southeastern Indian Ocean. Several of these drifters traveled across the Indian Ocean to the final destination near Reunion Island, very near where the wing debris was found, and the duration it took the drifters to make their trek was similar to that of the debris.

drifter diagram
 Diagram of a drifter. Illustration: NOAA

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Report helps scientists communicate how global warming is worsening natural disasters

Posted on 8 December 2016 by John Abraham &

Climate scientists have done a great job winning the scientific arguments about climate change. To be clear about what I mean, we have done a very good job investigating whether or not the Earth’s climate is changing (it is), what is causing the change (humans), how much will it change in the future, and what will be the impacts. 

There are no longer any reputable scientists who disagree with the principle view of that human emissions will cause climate change that will lead to societal and human losses (they already are). So, I use the term “win” here not to indicate it was a battle of “us” versus “them”. Rather, I mean “win” in that we have faithfully followed the scientific method, explored alternative hypotheses, checked and rechecked our work, and have come to a truth that is unassailable. We’ve done our job.

In the past, that is where our job ended. I mean maybe we would help with a press release on a breaking study, do an interview. But only rarely.

Now, particularly with an issue like climate change, that has such an impact on peoples’ lives, scientists are being asked to go further. We are being asked to effectively communicate to the public why this matters, what will happen if we take action or not, and what some trade-offs are. This means we can be put in an uncomfortable position where we’re forced to advocate. Some of my colleagues are understandably skittish about advocacy and avoid it religiously. Others, like myself, will advocate on occasion but be very clear about when the scientist hat comes off and the advocate hat is put on. 

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Fires and drought cook Tennessee - a state represented by climate deniers

Posted on 2 December 2016 by John Abraham &

With my new hope that deniers of climate change will take ownership of the consequences, I am sad to report that this week, terrible wildfires have swept through Tennessee, a southeastern state in the USA. This state is beset by a tremendous drought, as seen by a recent US Drought Monitor map. There currently are severe, extreme, and exceptional drought conditions covering a wide swath of southern states. The causes of drought are combinations of lowered precipitation and higher temperatures.

drought monitor

The patterns of drought are the result of many weeks of weather (warm and dry) that have led to the current conditions. The recent high-temperature map from NOAA below provides just one example.

US temps

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The simple, cheap instruments measuring global warming in the oceans

Posted on 23 November 2016 by John Abraham &

Earth is warming due to the release of heat-trapping greenhouse gases. Scientists are working hard to measure how fast the planet is warming, how much warming has occurred over the past few decades, and how this is affecting coastal areas, ecosystems, and fisheries. By understanding these factors, scientists can better project future climate impacts.

A large component of Earth’s warming involves the oceans, which absorb excess heat. The difficulty of gathering measurements in the oceans is that they are vast, deep, and often hard to reach. It’s also costly. Think about it: if you wanted to take the ocean’s temperature, how would you do it?

Centuries ago, ocean measurements were made with buckets dropped from the sides of ships. Over time, measurements have become more numerous and more accurate, partly thanks to technology advances. Today, a global array of floats that take continuous profiles of the upper ocean monitors ocean temperatures at more than 3000 locations to depths of 2000 meters. 

However, this array was put in place in 2005. Prior to that, the backbone of ocean measurements was a device or probe called the expendable bathythermograph (XBT for short). These small, torpedo-like probes, deployed from ships, gather temperature data to depths of 300 to 2000 meters as they descend through the water.

XBTs were designed as a simple, inexpensive way to obtain temperature measurements from virtually any ship. These XBTs were originally used by navies to determine the depth of the sound channel, where sound waves can travel thousands of miles. They were first introduced in 1967 and immediately adopted by scientists worldwide. Since their debut, several million have been deployed, with some 20,000 launched annually in all ocean basins. 

A very important and critical component of their success has been the excellent relationship established by the scientific community with commercial shipping companies. Commercial vessels aid scientists by voluntarily deploying XBTs along routes that are continuously repeated, often in remote regions not sampled by other types of oceanographic equipment.

With XBT use dating back to the 1960s, these measurements offer a unique historical perspective on temperature change in the oceans, which is often associated with global warming or even varying location and the intensity of ocean currents. XBT records, together with those of other observational tools later put in place, are crucial for determining how fast the ocean is warming - an essential factor for quantifying our effect on climate. XBT data are also used to measure how ocean currents change and how heat is transported across ocean basins, both of which are linked to extreme weather events worldwide. 

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Trump begins filling environmental posts with clowns

Posted on 17 November 2016 by John Abraham &

Come on, you can admit it. I admit it. I admit that after Trump’s election victory, I secretly hoped and even though that his rhetoric was worse than its bite. He only said those crazy things during the campaign to get elected. He wouldn’t really follow through on his plans to completely gut the US commitment to keeping the Earth habitable. Oh how naive we were. Trump’s plan to fill positions in his administration shows things are worse than we could have ever feared.

According to recent reports, Trump has picked long-time climate denier and spokesperson for the fossil fuel industry Myron Ebell to head the Environmental Protection Agency transition. This basically means the EPA will either cease to function or cease to exist. It also appears that the US will pull out of any agreements to limit greenhouse emissions. 

It means we have missed our last off-ramp on the road to catastrophic climate change. That may sound hyperbolic, but I study the rate that climate change is happening – the amount of heat accumulating in the Earth’s system. We didn’t have any time to waste in implementing Obama’s aggressive plans, and Trump will result in a decade of time lost.

So who is Myron Ebell? He is a director at the Competitive Enterprise Institute and chair of the Cooler Heads Coalition. Where did he get his PhD in science? Nowhere. In fact, he isn’t a scientist at all, but he does have a degree in economics. Yeah!

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Conservatives elected Trump; now they own climate change

Posted on 10 November 2016 by John Abraham &

Many of us in the United States are in deep shock and despair. The election of Donald Trump speaks of a country and a world that represents so many things that go against our deepest grains. However, as I told my children this morning, the Earth will still turn, the sun will still rise. In fact, a Trump presidency will not have the dire consequences that many of us fear – especially for people like me who will be insulated from his policies. Surely it will change the economics and courts in the US, among other things. But really, all of these are transient.

The one thing that isn’t transient is the impact this will have on climate change. It is now virtually certain the world will not meet any of its climate targets. If Trump (and the Republican-controlled Congress) stand by their pledges, we will see a major rollback of the tremendous progress that has been made on reducing emissions. A Trump presidency will likely set us back at least a decade, perhaps longer. And that is a decade we can’t afford.

The world will blow past the 2C (3.6F) target set in Paris. This means it will be difficult to avoid the worst consequences of climate change.

The election also affects how we should talk about climate change. In the US, and in many other countries, opposing steps to cut carbon pollution has become a litmus test for conservative politicians. So, in this sense, conservatives now own climate change. I can just imagine the slogans, “Climate change, brought to you by your neighborhood conservatives.”

George W Bush was the worst president ever on climate change. Back then, with the reality of climate change not as widely known, it is conceivable to give voters a pass. But not now. Anyone who voted for Trump shares the responsibility for what is now inevitable. 

It’s really too bad because many conservatives certainly don’t want to destroy the Earth’s climate. Furthermore, there are some conservatives who do take climate change seriously. However, when a central belief to conservatism results in decades of inaction, it makes it impossible to avoid staring facts in the face.

Conservatives own climate change.

Conservatives own the consequences of climate change.

They own the increased droughts, more severe storms, sea level rise, and floods.

They own the heat waves, the loss of habitat and the shifting climate zones.

They own the climate refugees, the resulting political strive, and climate conflicts.

They own it all.

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Barack Obama is the first climate president

Posted on 2 November 2016 by John Abraham &

My how far we’ve come in less than eight years. We have seen happen what those of us in the climate and energy fields knew could happen. The US has become a world leader on climate change, dramatically increased our production of clean and renewable fuels, reduced our emissions of greenhouse gases, signed major international agreements to continue progress into the future, and have done so without cost increases or power disruptions that the denial community proclaimed would occur.

As we in the United States get ready to elect a new president, it is helpful to think about the impact a president can have. Particularly since we transitioned from the worst climate president ever (Bush) to the best (Obama). I am going to detail what I think are Obama’s signature accomplishments.

In my mind, the most important part of President Obama’s legacy on climate is that he changed the conversation. He showed that not only should the US play a role in reducing emissions, but we can do just that. He showed that this problem isn’t too big to solve. In fact, most of the solutions are subtle enough that we don’t even notice them. He showed that we can change our future for the better.

With respect to specific actions, the Clean Power Plan is one of his biggest accomplishments. By working with the EPA, he created the first ever carbon pollution standards for the largest source of pollution – power plants. He did this in the midst of a do-nothing congress that fought him every step of the way.

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Global warming continues; 2016 will be the hottest year ever recorded

Posted on 21 October 2016 by John Abraham &

We know the world is warming – no factor can explain it aside from human emissions of greenhouse gases. Despite this, people who deny the basic facts of climate change have tried to argue that the Earth is either not warming or is only slowly heating. Well that just isn’t true anymore. The last three years are the nail in the coffin of the deniers of climate change. We have enough data this year to call 2016 as the hottest year ever record – and we have three more months left to go.

So, just how hot is 2016? Well my early predictions are shown in the graph below. I have taken temperature data from NASA and superimposed my predictions for 2016 – it isn’t even close. And by the way, it doesn’t matter whose data you use (NASA, NOAA, JMA, Hadley Centre) the results are the same. 2016 is going to blow 2015 out of the water.

GISTEMP

A few things to note. First, these temperatures are surface temperatures that are taken across the globe. But, you can measure temperatures elsewhere and see the same result. Most importantly, measurements in the oceans, where 93% of the extra heat is stored are the best proof of global warming. I recently coauthored an open-access paper on this very topic which interested readers can get here.

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Climate scientists published a paper debunking Ted Cruz

Posted on 14 October 2016 by John Abraham &

A new study has just appeared in the Journal of Climate which deals with an issue commonly raised by those who deny that human-caused climate change is a serious risk. As I have written many times, we know humans are causing the Earth’s climate to change. We know this for many reasons. 

First, we know that certain gases trap heat; this fact is indisputable. Second, we know that humans have significantly increased the amount of heat-trapping gases in the atmosphere. Again, this is indisputable. Third, we know the Earth is warming (again indisputable). We know the Earth warms because we are actually measuring the warming rate in multiple different ways. Those measurements are in good agreement with each other.

Of course there is other evidence too. For instance, ice loss across the globe is widespread: in the Arctic, the Antarctic ice shelves, Greenland, and from land glaciers. Sea levels are rising as warm water expands in volume and as melt waters flow into the ocean. We are also seeing changes of weather patterns and climatic zones shift. The point is, there is a whole body of evidence that proves the climate is changing and the change is caused largely by human emissions of greenhouse gases.

Over the years, contrarians have looked for evidence that the climate either isn’t changing or the change is not as fast as predicted. Their findings have often been used in the media to suggest that human-caused climate change was not something to worry about. But we’ve seen, over and over and over again, that these contrarian arguments don’t hold up. 

Repeatedly, mainstream scientists have taken these claims seriously and discovered they were just plain wrong. In some cases, the contrarians have made simple arithmetic errors (like mixing up a negative and positive sign in their equations), while in others, they have made more fundamental errors. But regardless, they have been wrong time after time. But whenever they are found to be wrong, they just go and find some new piece of evidence that once again calls into doubt our understanding of the human-climate link. 

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Caring for Creation makes the Christian case for climate action

Posted on 10 October 2016 by John Abraham &

From within this movement, there are huge voices, widely respected by both the scientific and faith communities. Perhaps the best known is Dr. Katharine Hayhoe, a top climate scientist who is also an evangelist Christian. There are other persons and organizations who work similarly to connect these two world viewpoints in a powerful yet common-sense way.

Recently a book has been published by a faith-science duo. That duo is Paul Douglas, respected meteorologist, entrepreneur, Republican, and Christian, and his writing partner Mitch Hescox who leads the Evangelical Environmental Network (the largest evangelical group devoted to creation care). Their book, entitled Caring for Creation, provides a masterful balance of science, faith, and personal journey.

The style of the book is one I have not seen before. It is a side-by-side presentation of first science, then faith, then science, and back to faith. Interspersed within the main text are enlightening anecdotes mainly from weather forecasters across the country which show an informed lived experience of experts watching the climate change before their very eyes. Importantly the authors provide a list of concrete things that we all can do, starting right now to make a meaningful impact in reducing global warming.

Within this book there is real science. Not just about what is happening now, but the history of climate science, how we’ve known since the 1800s that human emissions of greenhouse gases like carbon dioxide can warm the atmosphere. We also hear from Douglas about observed changes to the weather we all experience. This isn’t a problem for far-off times or far-away places. This is an issue that is being manifested now.

Hescox articulates a message grounded in the proposition that the creation is a gift from God and there is a real responsibility to care for it. Not only for others distant in time and space that may suffer, but for our own good. In fact, he argues persuasively that caring for this creation can help strengthen one’s faith.

Hescox also argues from a pro-life position. Caring for creation is the ultimate pro-life stance. Squandering resources and gifts will not only cause real harm to people and our economy, but it will endanger the lives of many of the most vulnerable.

Douglas provided a great summary:

I am a scientist but I believe in absolutes – I believe in more than I can observe, measure and test. The book of Genesis tells us that God made us in his self image. He gave us big, beautiful brains and the ability to think, reason, solve problems, make smart decisions, and improve our lives. He also gave us the good sense not to foul our nest.

Both of these intertwined stories of faith and science are woven together in a way that is easily accessible for non-scientists and people who are not of faith. We don’t need to be climate scientists or religious experts to get a lot out of the authors’ perspective. 

There are a few quotes from the book that do a great job of encapsulating the central themes which I will share. 

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The Madhouse Effect of climate denial

Posted on 26 September 2016 by John Abraham &

A new book by Michael Mann and Tom Toles takes a fresh look on the effects humans are having on our climate and the additional impacts on our politics. While there have been countless books about climate change over the past two decades, this one – entitled The Madhouse Effect - distinguishes itself by its clear and straightforward science mixed with clever and sometimes comedic presentation. 

In approximately 150 pages, this books deals with the basic science and the denial industry, which has lost the battle in the scientific arena and is working feverishly to confuse the public. The authors also cover potential solutions to halt or slow our changing climate. Perhaps most importantly, this book gives individual guidance – what can we do, as individuals, to help the Earth heal from the real and present harm of climate change?

To start the book, the authors discuss how the scientific method works, the importance of the precautionary principle, and how delaying actions have caused us to lose precious time in this global race to halt climate change. And all of this done in only 13 pages!

Next, the book dives briefly into the basic science of the greenhouse effect. Readers of this column know that the science of global warming is very well established with decades of research. But some people don’t realize that this research originated in the early 1800s with scientists such as Joseph Fourier. The book takes us on a short tour of history. Moving beyond these early works that focused exclusively on global temperatures, the authors come to expected impacts. They explain that a warming world, for instance, can be both drier and wetter!

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375 top scientists warn of 'real, serious, immediate' climate threat

Posted on 21 September 2016 by John Abraham &

Yesterday, 375 of the world’s top scientists, including 30 Nobel Prize winners, published an open letter regarding climate change. In the letter, the scientists report that the evidence is clear: humans are causing climate change. We are now observing climate change and its affect across the globe. The seas are rising, the oceans are warming, the lower atmosphere is warming, the land is warming, ice is melting, rainfall patterns are changing and the ocean is becoming more acidic.

These facts are incontrovertible. No reputable scientist disputes them. It is the truth.

Despite these facts, the letter reports that the US presidential campaign has seen claims that the earth isn’t warming, or it is only a natural warming, or that climate change is a hoax. These claims are false. The claims are made by politicians or real estate developers with no scientific experience. These people who deny the reality of climate change are not scientists. 

These claims aren’t new. We see them every election cycle. In fact, for the Republican Party, they are a virtual litmus test for electability. It is terribly sad that the party of Lincoln (the president who initiated the National Academy of Sciences) has been rebuked by the National Academy today. It is sad that the party of Teddy Roosevelt, who created the National Park System, is acting in a way antithetical to his legacy. It is also sad that the party of Nixon, who created the Environmental Protection Agency, now is trying to eliminate that very organization.

What is perhaps most sad is that the party of “fiscal conservatism” is leading us on a path that will result in higher economic and social costs for all of us.

What we don’t know is what the future will bring. Will the warming be gradual or sudden? Will ocean rise increase at a faster rate or not? Will we continue to see major ice shelf collapse? Increased droughts and heat waves? Will we be able to adapt?

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Climate change and other human activities are affecting species migration

Posted on 8 September 2016 by John Abraham &

One of the reasons climate change is such an important topic is that it will affect (and already is affecting) the natural biological systems. Both plants and animals will have to respond to the changing climate. In some cases, this means adapting to higher temperatures. In other cases, the changes may be alterations in the precipitation, length of growing season, availability or resources, or other influences. 

While some animals can adapt, others will have to migrate. Obviously migration can be apparent in mobile animals that will move to maintain a more or less similar climate to that to which they are accustomed.

But animal and plant movement does not occur in just a changing climate. It also has to navigate changes to the landscape that humans create. For instance, increased land allocation to agriculture or urbanization can create barriers for free migration. So, what scientists really want to know is how these two factors (climate change and land use change) will collectively affect the patterns of animal and plant movement.

A study that actually was published a few years ago but is only now getting press looked at this issue. The publication was authored by Julian Olden and his colleagues from the University of Washington and the Nature Conservancy. What they researchers found was very interesting. The study was published in the journal Ecology Letters and is titled Projected Climate-Driven Faunal Movement Routes.

First, they projected changes in the distribution of climatically suitable zones for projected future climates. They considered nearly 3,000 vertebrate species. Using a computer model, the projected how and when the species would migrate and they tracked the migration routes. The study incorporated a resistance to movement based on the amount of human alteration to the landscape. The analysis was similar to how the flow of electrons through a wire circuit is calculated. In fact, electronic circuit theory formed a basis for the calculations.

From their analysis, the authors identified several locations in North and South America that will be crucial for species movement in a changing climate. Large movements are expected in the southeastern US, the Amazon region, and parts of Brazil. Some of the areas where migration is expected have intact biological regions. Others, in particular the southeastern US and Brazil, have pathways that are heavily impacted by human activities, which may create a barrier to the migration routes.

In the study, the team of scientists first identified what they term “climatically suitable” conditions for each of the species under a changing climate scenario. They plotted routes for the species from areas that were projected to be unsuitable to these suitable areas. The routes were plotted so that they avoided the most heavily human-impacted regions. They then plotted the paths on a map for easy of visualization.

Some concrete and specific examples were provided. For instance, in the southeastern US, species are projected to move northward into the southern Appalachian Mountains. In South America, species are expected to migrate from central Argentina in the Pampas, Sierras de Cordoba, and Andes. The authors identified 14 biological regions and calculated the average direction of movement across each biome. Great visualizations are shown of paths of migrations, for instance, in the southeastern US.

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Vector image of migration patterns, southeastern USA. Illustration: Lawler et al. (2013), Ecology Letters.

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Global warming is melting the Greenland Ice Sheet, fast

Posted on 25 August 2016 by John Abraham &

A new study measures the loss of ice from one of world’s largest ice sheets. They find an ice loss that has accelerated in the past few years, and their measurements confirm prior estimates.

As humans emit heat-trapping gases, we expect to see changes to the Earth. One obvious change to be on the lookout for is melting ice. This includes ice atop mountains, ice floating in cold ocean waters, and the ice within large ice sheets or glaciers. It is this last type of ice loss that most affects ocean levels because as the water runs into the oceans, it raises sea levels. This is in contrast to melting sea ice – since it is already floating in ocean waters, its potential to raise ocean levels is very small.

So measuring ice sheet melting is important, not only as a signal of global warming but also because of the sea level impacts. But how is this melting measured? The ice sheets on Greenland and Antarctica are huge and scientists need enough measurements in space and time to really understand what’s going on. That is, we need high-resolution and long duration measurements to fully understand trends.

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Greenland Ice Sheet. Photograph: Briggs/CPOM

In a very recent publication in the journal Geophysical Research Letters, an international team reported on a new high-resolution measurement of Greenland. The lead author, Malcolm McMillan from the Centre for Polar Observation and Modeling, and his colleagues mapped Greenland with incredibly high resolution (5 km distances). 

They accomplished this mapping by obtaining data from the Cryosat 2 satellite. This satellite uses a technique called laser altimetry to measure the height of surfaces. It is able to track the elevation of the ice sheets on Greenland with high precision. If the height of the ice sheet is growing, it means the ice is getting thicker. If the heights are decreasing, it means the ice layers are getting thinner.

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Climate scientists make a bold prediction about sea level rise

Posted on 10 August 2016 by John Abraham &

One of the great things about science is that it allows you to make predictions. Three top climate scientists just made a very bold prediction regarding sea level rise; we should know in a few years if they are correct. 

As humans emit greenhouse gases, it’s causing the Earth to warm. That’s indisputable and proven. We can actually measure the amount of extra heat. Since most of it ends up in the oceans, we can also measure other changes in the oceans.

For instance, the oceans are rising. We know that’s indisputable. Measurements taken from physical gauges and from satellites confirm sea level rise. The cause of the rise is more complex. 

Part of the rise is from ocean warming – warm water is less dense so the sea level rises as temperatures increase. Another part of the rise is from melting ice, especially ice that is currently on land (like glaciers and ice sheets). As this ice melts and flows into the oceans, the water levels rise. A third reason for sea level changes is from alterations of where water is stored on the planet. For instance, changing rainfall patterns and storage of water underground, in lakes, or in the atmosphere can affect sea levels. 

The three ways we know sea levels are rising are from physical tide gauges, from satellites that measure the water height, and from satellites that measure where ice is stored across the globe. While tide gauge measurements go back many years, they only measure water levels at their location. Many tide gauges have to be in place to get an accurate sense of what is happening globally. 

Satellites, on the other hand, are much more capable of taking global measurements. The problem with satellites is they have only been taking measurements since approximately 1993 (not nearly as long as tide gauges). So scientists try to combine these two measurements to get a long-term and global picture of what is really happening. 

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Climate models are accurately predicting ocean and global warming

Posted on 27 July 2016 by John Abraham &

For those of us who are concerned about global warming, two of the most critical questions we ask are, “how fast is the Earth warming?” and “how much will it warm in the future?”.

The first question can be answered in a number of ways. For instance, we can actually measure the rate of energy increase in the Earth’s system (primarily through measuring changing ocean temperatures). Alternatively, we can measure changes in the net inflow of heat at the top of the atmosphere using satellites. We can also measure the rate of sea-level rise to get an estimate of the warming rate. 

Since much of sea-level rise is caused by thermal expansion of water, knowledge of the water-level rise allows us to deduce the warming rate. We can also use climate models (which are sophisticated computer calculations of the Earth’s climate) or our knowledge from Earth’s past (paleoclimatology). 

Many studies use combinations of these study methods to attain estimates and typically the estimates are that the planet is warming at a rate of perhaps 0.5 to 1 Watt per square meter of Earth’s surface area. However, there is some discrepancy among the actual numbers.

So assuming we know how much heat is being accumulated by the Earth, how can we predict what the future climate will be? The main tool for this is climate models (although there are other independent ways we can study the future). With climate models, we can play “what-if scenarios” and input either current conditions or hypothetical conditions and watch the Earth’s climate evolve within the simulation.

Two incorrect but nevertheless consistent denial arguments are that the Earth isn’t warming and that climate models are inaccurate. A new study, published by Kevin Trenberth, Lijing Cheng, and others (I was also an author) answers these questions.

The study was just published in the journal Ocean Sciences; a draft of it is available here. In this study, we did a few new things. First, we presented a new estimate of ocean heating throughout its full depth (most studies only consider the top portion of the ocean). Second, we used a new technique to learn about ocean temperature changes in areas where there are very few measurements. Finally, we used a large group of computer models to predict warming rates, and we found excellent agreement between the predictions and the measurements.

According to the measurements, the Earth has gained 0.46 Watts per square meter between 1970 and 2005. Since, 1992 the rate is higher (0.75 Watts per square meter) and therefore shows an acceleration of the warming. To put this in perspective, this is the equivalent of 5,400,000,000,000 (or 5,400 billion) 60-watt light bulbs running continuously day and night. In my view, these numbers are the most accurate measurements of the rate at which the Earth is warming.

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The best strategies to keep bodies cool in a heatwave, according to researchers

Posted on 21 July 2016 by John Abraham &

As we hit high-heat season in the Northern Hemisphere, it is useful to clarify tactics that can be used to help maintain healthy body temperatures. These tips are not commonly known and can be adopted by anyone, anywhere. While I am a climate scientist, my funded work is in the area of heat transfer, particularly in the human body. I work with medical companies to maintain healthy body temperatures during surgeries or other situations. I also deal with scald burns and I often serve in burn injury litigation.

Here are some key tips. First, avoid hyperthermia in the first place – drink plenty of fluids, avoiding direct sunlight, trying to get a respite from heat each day, avoiding physical exertion during the hottest parts of the day are all great suggestions. But, if you need to lower a body temperature, Dr. Robert Huggins, VP of Research and Athlete Performance at the Korey Stringer Institute suggests:

The general rule is to cool as much of the body’s surface as possible …. the larger the area you cool and the colder the device you use to cool it the faster the cooling rate. An appropriate goal is to use a method that cools at a rate of 0.15°C per minute. This can typically be achieved by immersion techniques using a tub or other basin filled with ice cold water or via rotating cold ice towels over the body.

During exercise if there is limited access to the entire body (e.g. football or fire-fighters), cooling the hands, face and feet will help, and if possible, use a fan to increase evaporation from these surfaces. However, when heat stroke is suspected, these strategies are not nearly as effective as whole body methods; opt for immersion cooling.

So how do you know if someone is suffering from hyperthermia or heat stroke? A great resource is the Korey Stringer Institute, which lists many symptoms for heat stress such as fatigue, weakness, pale appearance, headache, nausea, vomiting, fainting, dizziness, and others. The heat stroke treatment they recommend, while geared toward athletes, is still useful for the rest of us. 

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Humans are greening the planet, but the implications are complicated

Posted on 15 July 2016 by John Abraham &

The Earth’s climate is changing – in fact, it always changes. But in the current context of human influence, scientists try to decipher how much of the change is natural compared to human-induced.

One clear way humans influence the Earth is through the biosystem. For instance, farming changes the biosystem. By removing natural growth and planting annual crops that are harvested, we change the system in a way that could in turn affect other parts of the Earth system. In addition, the use of nitrogen based fertilizers can increase growth rate and lead to a greening of areas that are subject to fertilization. 

Another more indirect potential for humans to alter plant growth is through fertilization involving carbon dioxide. We know that humans have increased the amount of carbon dioxide in the atmosphere by approximately 40%. We also know that airborne carbon dioxide is a fertilizer for plants. So the obvious question is, “do our carbon emissions affect plant growth?”.

A new study, just out in Nature Climate Change, helps answer that question. This study focused on land areas in the northern hemisphere that were outside the tropical region. They obtained information from satellites to measure the greening of these lands areas to determine whether there was any significant change. The find that yes, in fact there is. Over approximately 30-year durations, this area has indeed gotten greener.

So, the next question is, what is causing the greening? To answer this question, the authors used computer simulations and ran them with and without human influences. When we say “human influences” we can mean many things, such as increase or decrease of farming, use of fertilizers, and airborne increase of carbon dioxide, just to name a few. The authors found that the only way the simulations matched the observations is when these human influences were included. That is, solely natural variations cannot be the cause. Not only that, but the match worked best when airborne carbon dioxide had a major role.

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The spatial distribution of the linear trends in the growing season (April–October) leaf area index during the period 1982–2011 in the mean of satellite observations (upper figure), Earth system model (ESM) simulations with natural forcings alone (lower left figure), and ESM simulations with anthropogenic and natural forcings (lower right figure). Illustration: Oak Ridge National Laboratory

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The War on Science will change how you see the world

Posted on 1 July 2016 by John Abraham &

Every so often a book comes along that changes the way you view the world. The War on Science: Who’s Waging It, Why It Matters, What We Can Do About It by Shawn Otto is one of those rare books. If you care about attacks on climate science and the rise of authoritarianism, if you care about biased media coverage or shake-your-head political tomfoolery, this book is for you. 

Cover of the book The War on Science

Otto, an organizer of the US Presidential Science Debates and a global speaker on science and democracy, started on the journey that led to this book in late 2007, when he noticed that the candidates weren’t talking about any of the big science, technology, health and environmental issues. 

Furthermore, the news media weren’t asking questions about these subjects even though they were impacting voters at least as much as economics and foreign policy. In fact, the top five TV news anchors asked the candidates 2,975 questions in 171 interviews, and just six mentioned the words “global warming” or “climate change,” the single largest environmental and economic question to face the planet. To put that in perspective, three mentioned UFOs.

Flash forward eight years. In the week following the Paris climate accord, both the Democrats and the Republicans held presidential primary debates. Yet just days after 195 countries reached an historic agreement to begin rebuilding the world’s economy around clean energy, no journalist in either debate asked a single question about it.

This is par for the course for journalists and politicians who mostly went into the humanities after high school, says Otto. But it’s a problem when science is impacting every aspect of life on the planet, and having more and more concrete things to say about public policy.

Thomas Jefferson would be appalled. Otto traces how Jefferson appealed to scientific thinking when drafting the Declaration of Independence, narrowly circumscribing his argument around the idea that if anyone can establish the truth of something using the tools of reason and science, no pope or monarch had any greater authority to rule than we do ourselves. Science was the great equalizer. “Wherever the people are well-informed,” Jefferson later wrote, “they can be trusted with their own government.” To secure this, he championed a free press and public education.

But according to Otto, this places an ever-increasing burden on the voter, and in an age when science has grown mind-bogglingly complex, public education and the press are unduly influenced by corporations focused on financial outcomes, religious extremists intent on forcing biblical literalist policies, and postmodernist academics who’ve laid the foundation for all this by teaching that science is but one of many equally valid “ways of knowing” and that all truth is relative.

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New methods are improving ocean and climate measurements

Posted on 20 June 2016 by John Abraham &

I have often said that global warming is really ocean warming. As humans add more heat-trapping gases to the atmosphere, it causes the Earth to gain energy. Almost all of that energy ends up in the oceans. So, if you want to know how fast the Earth is warming, you have to measure how fast the oceans are heating up.

Sounds easy enough at first, but when we recognize that the oceans are vast (and deep) we can appreciate the difficulties. How can we get enough measurements, at enough locations, and enough depths, to measure the oceans’ temperatures? Not only that, but since climate change is a long-term trend, it means we have to measure ocean temperature changes over many years and decades. We really want to know how fast the oceans’ temperatures are changing over long durations.

But that isn’t all. Throughout the years, we have made changes to the measurement methods. From old canvas buckets that were dipped into waters which were then measured, to insulated buckets, to temperature probes on the hulls of ships, devices that would be dropped into deep ocean waters, and now the ARGO fleet, which is approximately 3,000 autonomous devices that are more-or-less equally distributed across the oceans. Each of these devices measures temperatures a little differently; they have biases. As you change from one set of instruments to another, you might see a cooling or warming effect related to the change in instruments, not because the water temperatures are changing. 

The seeming intractability of this problem is why I began studying it a few years ago. I have worked with colleagues to answer a very specific equation related to one of the most commonly employed ocean measurement devices, the eXpendable BathyThermograph (or XBT for short). For many years, these devices formed the backbone of ocean temperature measurements. My colleagues and I want to ensure measurements from XBTs are as accurate as possible.

These devices are used by navies to measure the depth of the thermocline. While that was their original mission, climate scientists have adopted the devices for determining long-term ocean temperature changes. The problem is that the devices are relatively simple; they are freely dropped into ocean waters. As they descend, like a spinning torpedo, they unwind a wire connected to a computer system on-board the ship. A sensor in the probe sends temperature information to the computer system and a recording is made. When the device expends its wire, the wire breaks and the device continues to fall until it impacts the ocean floor.

It’s important for scientists to know the depth of each temperature measurement that the probe makes. The problem is, the probe does not detect its depth. Rather, its depth is estimated by knowing how fast the probe falls in water. The probe weight is balanced by drag forced between the water and the device. If the knowledge of probe speed is not known accurately, it means a scientist may think the probe is at one depth when in fact, it’s at a different depth. This subtle uncertainty can lead to large uncertainties in the overall ocean heat content.

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Climate scientists have warned us of coral bleaching for years. It's here

Posted on 10 June 2016 by John Abraham &

Readers may have noticed that it’s been about a month since my last article. In recent weeks I presented guest articles in place of my own pieces. The reason for my absence was due to the adoption I was finalizing in the USA (my second successful adoption!). Anyone who has adopted a child can attest to the time and travel requirements. I intend that this article marks my return to near weekly posting and I thank my readers for their patience.

Coral reefs are important for the health of the ocean biosystem; they support and harbor a high density of diverse organisms. While there are reefs located in many locations around the world, people often think first about the Great Barrier Reef off the Australian coast. It is known for its size and beauty; it brings travelers close to nature.

Scientists have investigated how reefs will fare in a changing world. The changing climate, poor management, pollution, overfishing, careless divers, and other factors may bring real risks to the health of reefs.

Just a few days ago, a world-leading organization released the results of a long-term study on the health of the Great Barrier Reef that may tell us about the health of reefs around the world. The organization ARC Centre of Excellence Coral Reef Studies found that a recent mass bleaching has killed 35% of corals on the northern and central Great Barrier Reef. 

The National Oceanic and Atmospheric Administration explains coral bleaching as events that cause the coral to expel algae that live in their tissues. Following the expelling, the corals whiten in color (which is why the term bleaching is used). The coral and the algae live in a symbiotic relationship; the algae provide nutrients for the coral. Without the algae, coral can be more susceptible to disease and death. It’s important to know that the coral can recover from a bleaching, but recovery depends on the extent and duration of the event and the general health of the coral.

This year’s incredible bleaching is not a one-time event. In fact, there have been many significant regional bleaching events and three global events over the past 18 years. In the current event, the extent of bleaching depends on location. The Great Barrier Reef extends over 2000 km. In the northern sector, almost all reefs experienced bleaching. The further south one travels, the less extensive the event because the warming was not as severe.

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Map of estimated coral loss on the Great Barrier Reef in June 2016, Australia. Illustration: ARC Centre for Excellence in Coral Reef Studies

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Peabody coal's contrarian scientist witnesses lose their court case

Posted on 2 May 2016 by John Abraham &

In Minnesota, an administrative hearing resulted in a judicial recommendation that will have impacts across the country. It was a case argued mainly between environmental groups (such as Minnesota Center for Environmental Advocacy, and their clients Fresh Energy and the Sierra Club) and energy producers (such as the now-bankrupt coal company Peabody Energy) regarding what a reasonable social cost of carbon should be.

I was called as an expert witness in the case along with respected climate scientistDr. Andrew Dessler. We were opposed by the well-known contrarians Drs. Roy SpencerRichard Lindzen, and William Happer (who has recently received attention related to his charged fees in the case). In full disclosure, Dr. Dessler and I were not paid for our work in the case. I recently wrote about the testimony and provided links to the testimonies submitted for the case. The judge’s recommendations and how they will impact energy decisions in the USA were the keys to this trial.

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El Niño is Earth's rechargeable heat battery

Posted on 15 April 2016 by John Abraham &

The recent El Niño has been in the news of late because the warm waters in the Pacific have helped lift Earth’s temperatures to new records. Recent research is helping to track energy flows between the ocean waters and the atmosphere as the El Niño builds, then slowly decays and even changes to a La Niña. This new information is an important advancement of our understanding of the Earth’s climate.

As a background, a part of the Pacific Ocean flips between cold (La Niña) and warm (El Niño) phases over a few-year-long period. Sometimes the oceans are in neither a cold or warm phase, and we call that neutral.

The flipping back and forth always occurs, but the duration and regularity can change. In general, the cycles occur over 3 to 7 years, sometimes with longer duration, other times shorter. But regardless, this El Niño/La Niña process is really important for the rest of the world. It affects the whole atmosphere through what are termed teleconnections.

Consider for instance a situation when the waters are warm (El Niño), resulting in more evaporation from the ocean waters into the atmosphere. Conversely when the ocean waters are cold, there is often less evaporation. Because evaporation requires a great deal of thermal energy – it cools the ocean while moistening the atmosphere – it’s an engine that moves heat. 

Simply put, the El Niño–Southern Oscillation (ENSO; the latter is in the atmosphere) cycle can supercharge this movement of energy, or it can temporarily sequester the heat. But regardless, once the energy gets into the atmosphere, it changes the atmospheric winds around the globe and affects weather elsewhere.

So, a new study, led by Dr. Michael Mayer from the University of Vienna, focused on the energy flows during the ENSO process. The study recalls prior work that has led to a view of ENSO that is a bit like a rechargeable battery. During La Niña, heat builds up in the Pacific and then during El Niño, the heat is dissipated to other regions. The dissipation occurs in both laterally via atmospheric energy transports and vertically via radiation to space. When the warm water moistens the air (through evaporation), it invigorates storms and flow of energy in the atmosphere. As a result of these teleconnections, a substantial fraction of the heat released from the Pacific during El Niño subsequently appears in the Atlantic and Indian Oceans.

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New survey finds a growing climate consensus among meteorologists

Posted on 28 March 2016 by John Abraham &

There have been multiple scientific studies that all concur: scientists know that climate change is happening and it is largely caused by humans. I recently wrote about this here, where I reviewed the studies. It turns out that the more scientists know about climate change, the more they are convinced that humans are warming the planet. In fact, the consensus is extraordinarily strong. But it isn’t just that the vast majority of scientists agree; it’s that the best scientist agree. We find that the contrarian scientists tend to be less accomplished, have had their research found to be incorrect time after time, and they produce less science. 

But very recently, a study from the George Mason University Center for Climate Change Communication was completed that adds to our knowledge on the consensus. Lead author Ed Maibach and his colleagues are very well-respected surveyors and scientists who study this topic. The study didn’t focus on what we think of as climate scientists – rather they polled meteorologists. 

There were actually two surveys that were merged. In one, the authors identified 1038 professionals currently working in broadcast meteorology from the American Meteorological Society (AMS). In a concurrent study, the authors obtained a list of members from the AMS who were not broadcast meteorologists. The two groups were asked a series of questions on whether climate change is occurring, the degree to which respondents felt humans were responsible, what could be done to minimize climate change, among others. The authors also asked about the educational background of the respondents.

Not all members of the AMS are meteorologists. Additionally, someone working in meteorology is not necessarily a climate scientist. Similarly, a climate scientist is not necessarily a meteorologist. Sometimes these populations overlap but in many cases they do not. 

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Worst Mediterranean drought in 900 years has human fingerprints all over it

Posted on 18 March 2016 by John Abraham &

In a warming world, we expect to see increases in some extreme weather events. The science is pretty clear that in some parts of the world, drought and heat waves have and will continue to increase. In other areas, more severe storms along with precipitation and flooding have increased. Drought, heat waves, and floods are examples of changes to weather and climate patterns that will have costs for human society. 

It’s tricky to discern not only whether past extreme weather have changed, but also whether human-caused global warming is a factor. Scientists need high-quality records that go back many decades to see if there is any trend towards increasing or decreasing extreme weather. But weather is quite variable. We can see a rise or fall in extreme weather events with no apparent cause, human or natural. 

While these trends tend to be shorter (over days, weeks, or perhaps months), some trends can have longer durations. How can we identify trends prior to high-quality instrumentation and how can we discern whether the extreme weather we see now is within natural variability? Those are the questions addressed in a new publication in the Journal of Geophysical Research by lead author Dr. Benjamin Cook and his colleagues.

The title of the article, “Spatiotemporal drought variability in the Mediterranean over the last 900 years” clearly indicates that this study considers almost a millennium of drought records and focuses attention on the Mediterranean region.

The authors use a powerful database called the Old World Drought Atlas to look back in time prior to modern instruments. This atlas is a collection of tree-ring data that measures drought using the Palmer Drought Severity Index. Within the Mediterranean region, there are 106 different tree-ring datasets. These datasets go back various lengths of time but since 1100 CE, the region is accurately sampled. 

The Palmer Drought Severity Index accounts for changes in precipitation as well as changes in evaporation and storage of water within soils. By using this measurement, the authors are able to find multiple droughts throughout the Mediterranean region. Often times, the droughts occur simultaneously in different parts of the region. For instance, droughts are likely to occur at the same in in both the Western Mediterranean (Spain, Portugal, Morocco, Algeria, Tunisia) and in the east (e.g. Greece and Turkey).

What did the authors find regarding the recent droughts in the Mediterranean? Well in recent decades, there has been a persistent and long-duration drought in the regions of Greece and the Levant region. The authors found that although the Greek droughts have been severe, they do not deviate from droughts that have been observed in the past.

In the Levant region, the recent drought (1998–2012) exceeds what they have seen in the past 900 years. In fact, the recent drought is likely the driest period in the last 900 years and very likely the driest period in the last 500 years.

Here is what Dr. Cook told me:

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Sea level rise is accelerating; how much it costs is up to us

Posted on 11 March 2016 by John Abraham &

As humans emit heat-trapping gases into the atmosphere, it’s causing the Earth to warm. It’s also causing the ocean waters to rise. In fact, water rise is one of the clearest signatures of a warming world. The questions we want to answer are, how much will sea levels rise, and how fast? 

The answers to this have large implications on what societies should do. It isn’t just coastal communities that will be affected. While there are approximately 150 million people worldwide that live within 3 feet of today’s water levels, because of the interconnected economies and societies, ocean rise will affect us all.

The prestigious Proceedings of the National Academy of Sciences recently published a series of sea level rise papers.

One paper covers the Antarctic ice sheet, and the authors look back in time at the world’ largest ice sheet. The authors use three tools to advance our knowledge of the ice. First, they use a very accurate calculation approach to quantify how the ice sheet interacts with the atmosphere. Second, they incorporate potential ice fractures into their analysis. Finally, they use information about changes to oxygen isotopes to improve their calculations. What they find is that the atmospheric concentration of carbon dioxide will soon be at levels not encountered since the Miocene period (23 million to 5 million years ago). They also find that newer computer calculations do a better job of quantifying changes to the ice sheet.

A second paper published by Roelof Rietbroek and colleagues looked at the sources of sea level rise. They wanted to know how much of the current rise is from water that is warming and expanding, how much is from melting of ice sheets in Greenland and Antarctica, how much is from melting glaciers, how much is from shifting continents, etc. 

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Climate scientists worry about the costs of sea level rise

Posted on 2 March 2016 by John Abraham &

As humans add greenhouse gases to the atmosphere, it not only warms the planet, but also raises the oceans. Ocean waters are rising for a number of reasons including thermal expansion of water (as water warms, it expands to a larger volume), as well as ice melt which then flows as liquid into the ocean. My next post will cover four recent studies that quantify how much ocean levels will rise in the future. However, here I will focus on the economic costs of rising seas.

A paper was just published by Drs. Boettle, Rybski and Kropp that dealt with this question. The authors of this study note that if you are concerned about societal and economic costs, the rate of sea rise isn’t the entire story. Much of the damage is caused by extreme events that are superimposed on a rising ocean. Damage is highly nonlinear with sea rise. 

To explain this, let’s think about flooding. Consider a river that has a dike system capable of confining a rise of water up to six feet. Such a system would have little or no economic/societal damage for “floods” up to six feet, but just one more foot of water rise would put the waters over the dike and could cause significant losses. So what really matters is, do events overshoot some level that commences damage?

How does this relate to climate change? Well as we warm the planet we are raising the baseline level of water from which extremes happen. Second, we are making some extreme weather events more likely. To measure the changes to extreme events in the future, the authors use a statistical method to estimate economic losses from coastal flooding. Using Copenhagen and other locations as test cases, they found that economic losses double when water rises only 11 cm. They also find that the costs rise faster than sea level rise itself. So, if we expect a linear increase in sea level over the next century, we should anticipate costs that increase more rapidly.

The authors also look at what are called “tail events” of storm surges. These are unusual events that can cause a large fraction of losses. Superstorm Sandy is an example; the storm surge from that event was very extreme and cause more loss than the combination of many smaller storm surge events.

I asked the authors why this study is important. They told me,

While there is considerable progress in the understanding and projections of future sea level rise, there is little understanding about the damage costs from coastal floods which are expected to intensify with sea level rise. Most work focuses on case studies and there was no general understanding. Due to limited funds for adaptation it is very valuable to have a transferable and comparable approach for any coastal region.

I also asked how this work was novel and different from prior research.

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Fossil fuel funded report denies the expert global warming consensus

Posted on 22 February 2016 by John Abraham &

We all know about the various organizations that fund or support the climate-change denial industry. Perhaps the best known is the Heartland Institute, which actually puts on climate “conferences” and publishes materials that appear at first glance to be scientifically sound. We who work and follow the climate change science and public discussions know enough to be skeptical about anything produced by groups like the Heartland Institute – their veneer of scientific credibility is very thin. 

On the other hand, perhaps the intended audience isn’t scientists or even people who closely follow the science. Perhaps their intended audience is legislators, teachers, and others who have influence over society?

With this as a backdrop, I received a copy of a humorous report from an elected official in the USA. The report was entitled “Why Scientists Disagree about Global Warming,” published by Heartland. Since elected officials have too much going on to do a thorough debunking, I looked into this report to see what substance was there.

As a scientist, when I read any manuscript I ask a number of questions. Who wrote it and what is their expertise in the field? When statements and conclusions are made, what is the evidence? How do these conclusions fit into prior work in the field? Is the new study confirming prior work or in conflict with it? If there is conflict, why?

The authors of this manuscript are Craig Idso, the late Robert Carter, and Fred Singer. These three are not exactly (or even nearly) a trio of reputable climate scientists. According to a literature search performed using the search engine SCOPUS, neither Idso nor Singer published a credible paper on global climate change or its implications in years.

One way to measure the authors’ impact is by counting how many people have read and cited their work. For both of these authors, the number of people who have cited them is shockingly low. To put their impact in perspective, a scientist like Kevin Trenberth receives three times more citations each year than the combined citations of Singer and Idso in their entire careers. So, having these guys be lead author on a climate change document is a bit like hiring retired scientists or op-ed writers to do your research. 

But just because they are not active and reputable scientists, could they be correct? Sure, they could be. So let’s look at the content.

The central theme of this manuscript is an attack against the expert consensus on human-caused global warming. The consensus refers to the very strong and repeatable measure of what scientists think about climate change. What do the best scientists say?

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The gutting of CSIRO climate change research is a big mistake

Posted on 10 February 2016 by John Abraham &

Last week, surprise news shocked the world’s scientific community. One of the most prestigious and productive scientific organizations is slashing hundreds of jobs, many related to climate change research. The organization, the Commonwealth Scientific and Industrial Research Organization (CSIRO for short) is simply put, one of the best in the world. It rivals well-known groups like NASA, NOAA, and the Hadley Centre for its contributions to climate science.

What does CSIRO do that is so special? Many things. For instance, they are world leaders in measuring what is happening to the planet. Their research includes ocean-going vessels and other instrumentation that measure the chemistry and temperature of the ocean; they help track where human-emitted carbon dioxide is going, how heat is building up in the oceans, and what is happening with the general health of the ocean biosystem.

CSIRO is also a modeling superpower. Their climate models form the backbone of our understanding of what changes have happened and what changes will happen because of human greenhouse gases.

But they also have deepened our knowledge about extreme weather. They’ve provided insights regarding how droughts, heat waves, and floods will change in the future.

All of these contributions are important not only for the understanding that they provide but also because this knowledge helps us plan for the future. If you want to know what we can do to mitigate or adapt to climate change, you need this information.

But according to CSIRO chief executive, Larry Marshall, CSIRO should shift focus. Here is the key statement he made last week:

Our climate models are among the best in the world and our measurements honed those models to prove global climate change. That question has been answered, and the new question is what do we do about it, and how can we find solutions for the climate we will be living with?

Are you kidding me? What kind of backward logic is this? From the reports I’ve read, something like 350 positions will be cut from CSIRO with the heaviest cuts (over 100) coming from the climate research groups. How can you predict how to adapt if you don’t know what you are going to adapt to? This doesn’t make sense. 

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Measuring ocean heating is key to tracking global warming

Posted on 3 February 2016 by John Abraham &

Human emissions of greenhouse gases such as carbon dioxide are causing the Earth to warm. We know this, and we have known about the heat-trapping nature of these gases for over 100 years. But scientists want to know how fast the Earth is warming and how much extra energy is being added to the climate because of human activities.

If you want to know about global warming and its future effects, you really need to answer these questions. Whether this year was hotter than last year or whether next year breaks a new record are merely one symptom of a warming world. Sure, we expect records to be broken, but they are not the most compelling evidence. 

The most compelling evidence we have that global warming is happening is that we can measure how much extra heat comes in to the Earth’s climate system each year. Think of it like a bank account. Money comes in and money goes out each month. At the end of the month, do you have more funds than at the beginning? That is the global warming analogy. Each year, do we have more or less energy in the system compared to the prior year? 

The answer to this question is clear, unassailable and unequivocal: the Earth is warming because the energy is increasing. We know this because the heat shows up in our measurements, mainly in the oceans. Indeed the oceans take up more than 92% of the extra heat. The rest goes into melting Arctic sea ice, land ice, and warming the land and atmosphere. Accordingly, to measure global warming, we have to measure ocean warming. Results for 2015 were recently published by Noaa and are available here.

A recent paper by Karina von Schuckmann and her colleagues appeared in Nature Climate Change, and provides an excellent summary of our knowledge of the energy balance of the Earth and recent advances that have been made. The article describes the complexity of the situation. The Earth is continuously gaining energy from greenhouse gases, but there are also natural fluctuations that cause both increases and decreases to the energy flows. 

For instance, volcanic eruptions may temporarily reflect some solar energy back to space. Natural variability like the El Niño/La Niña cycle can change heat flows and how deep the heat is buried in the ocean. The energy from the sun isn’t constant either; it varies on an 11-year cycle, but by less than 0.01%. With all of this and more happening, how do we know if an energy imbalance is natural or human caused? How do we separate these effects? 

The effort to separate human from natural effects is seen to be possible when one considers how the imbalance is measured in the first place. There are multiple complementary ways to make these measurements. Each technique has advantages and disadvantages and they have to be considered together.

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Study finds slim odds of record heat, but not as slim as reported

Posted on 27 January 2016 by John Abraham &

No, this isn’t another article about how damn hot 2015 was. Although just between us, I may have lost a bet to climate seer Joe Romm because he correctly predicted 2015 would blow 2014 out of the water. Instead, this is a post about the probability that temperature records keep getting broken if climate change is natural.

A paper just published in Nature Scientific Reports by Michael Mann and Stefan Rahmstorf and their colleagues considered this question. In particular, they wanted to know how likely recent temperature records and the string of records would be if the climate was completely driven by natural variations. Not even including the crazy-hot 2015, what did the authors find?

Well it depended on the “record” they looked at. For instance, the likelihood that 13 of the hottest 15 years would be in the past 15 years is 1 in 10,000. The likelihood that 9 of the 10 hottest years occur in the past decade is 1 in 770. The results are similar regardless of whose temperature dataset is used.

Some media stories reported that the temperature records were even more unlikely. The reason this study arrived at different results is that they took into consideration the fact that temperature records are not like coin-flips. Each year is not independent of another year or the prevailing situation. 

For instance, there are natural events that alter the temperature such as volcanoes, variations in the solar output, or even internal variability such as the La Niña/El Niño cycle. If climate change were all natural, you could get these natural events to align just by chance, and this could give a naturally-occurring record. So, while it’s very unlikely that this could occur, it is much more likely than if we just treated each year as a coin flip.

The authors then asked how likely it would be to have a string of records given the reality of human-caused warming. They found that it’s 83% likely that 9 of the last 10 years would be the hottest on record and 76% likely that 13 of the past 15 years were hottest on record. They also found that the odds of 2014 being the hottest year on record was 40%. Without human influences, that chances 2014 would have been the hottest year is approximately 1 in a million. Mann said:

The press reports last year about the unlikely nature of recent global temperature records raised some very interesting questions, but the scientists quoted hadn’t done a rigorous calculation. As a result, the probabilities reported for observing the recent runs of record temperature by chance alone were far lower than what we suspected the true probabilities are.

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A striking resemblance between testimony for Peabody Coal and for Ted Cruz

Posted on 20 January 2016 by John Abraham &

In a recent congressional hearing, Ted Cruz (one of the leading candidates for the Republican presidential nomination) first asked us to follow the science, and then misused and abused the very science he reportedly admires. The contrarian scientists that were invited to testify are members of a shrinking tribe that every year has to work harder to deny the clear evidence of a human-caused warming world.

Those scientists were William HapperJudith Curry, and John Christy. They argued that the Earth isn’t warming (or has slowed its warming) or that satellite temperature measurements are the best way to measure the Earth’s temperatures. In fact, satellites don’t measure temperature at all, but these witnesses didn’t mention that fact. 

Additionally, the satellite measurements that they showed are from the middle of the troposphere, high in the atmosphere (not at the surface). Finally, the contrarians declined to emphasize that the synthetic satellite temperature data have been wrong for years. The upper part of the atmosphere (stratosphere) is cooling as a result of the increased greenhouse gases while the lower layer (the troposphere) is warming. If any measurements of the stratosphere bleed into the measurements of the troposphere, it can cause a cooling bias.

I had the (dis)pleasure of testifying at a hearing in Minnesota where William Happer also testified. He, Roy Spencer, and Richard Lindzen all made errors in their testimony that were repeated at the Cruz congressional hearing. At the Minnesota hearing, these contrarians were representing Peabody Energy – the world’s largest private sector coal company.

They focused on high-altitude temperatures in the tropical part of the globe (near the equator) rather than temperatures at the surface or in the oceans. But it gets even worse – they combined two sets of satellite data into a single curve when in reality, satellite temperature measurements differ by as much as a factor of four depending on whose data you use! 

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