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Climate Hustle

Explaining climate change science & rebutting global warming misinformation

Scientific skepticism is healthy. Scientists should always challenge themselves to improve their understanding. Yet this isn't what happens with climate change denial. Skeptics vigorously criticise any evidence that supports man-made global warming and yet embrace any argument, op-ed, blog or study that purports to refute global warming. This website gets skeptical about global warming skepticism. Do their arguments have any scientific basis? What does the peer reviewed scientific literature say?

 


2016 SkS Weekly News Roundup #7

Posted on 13 February 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Feb 7

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The new age of climate exploration

Posted on 12 February 2016 by Guest Author

On December 12, the 21st annual meeting of the world’s climate negotiators closed with adoption of the Paris Agreement. The task agreed by consensus among 195 nations is clear, ambitious, and complex: re-engineer the infrastructure of the global economy to eliminate practices that destabilize Earth’s climate system, while ensuring ongoing and expanded prosperity for all people everywhere.

That the task is difficult should not put us back on our heels. As we move into new territory, we will face new obstacles. This is how we learn, how we know if we are up to the challenge, how we know which adjustments to make, and how we succeed in crossing an unknown ocean.

For centuries, explorers have sought to navigate the Northwest Passage—a shortcut from Europe to Asia that wouldn’t require sailing around the southern extremes of Africa or South America. For much of that time, the idea was something between a flight of fancy and a dangerously unapproachable challenge. Many have died making the attempt.

Twenty-one years ago, in the summer of 1994, a 57-foot fiberglass sailboat named Cloud Nine set sail, with captain Roger Swanson at the helm. Cloud Nine carried a crew of six, who were attempting to transit the fabled Northwest Passage from east to west. There was a tremendous amount of pack ice choking off all the routes through the Passage that summer, and the crew of Cloud Nine was forced to abandon the voyage and retreat out of the Arctic.

northwest passage

In Barrow Strait, near the Canadian village of Resolute, Cloud Nine encountered dense pack ice that could trap and sink even a larger vessel. The crew were forced to turn back to ensure their survival. Photograph: David Thoreson

Thirteen years later, in the summer of 2007, Cloud Nine returned to the Arctic for another east-to-west attempt. This time around, the crew of six discovered little to no ice in the Northwest Passage. To the astonishment of those on board and of those watching their transit, the nearly 7000-mile voyage took only 73 days, and Cloud Nine never touched one piece of ice.

NW passage

Shot at the same place as the above photo from the 1994 expedition, this 2007 photo clearly shows open water where there should be close and dangerous pack ice. Photograph: David Thoreson

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Onset of Eocene Warming Event took 3-4 millennia (so what we’re doing is unprecedented in 66 million years)

Posted on 11 February 2016 by howardlee

This article goes into more depth, and has more quotes from my interviews with Professor Richard Zeebe and Professor Andy Ridgwell, than the original article I wrote for The Guardian, published January 29.

The Paleocene-Eocene Thermal Maximum (PETM) was a global warming event with a relatively rapid onset that occurred 56 million years ago at the boundary between the Paleocene and Eocene geological epochs. Scientists have been studying the event because it is seen as an analog, albeit an imperfect one, of modern climate change.

How much warming?

With a global warming of 5º or 6ºC, it is the strongest warming episode to affect the planet in the time since the end-Cretaceous 66 million years ago (when the dinosaurs went extinct). Unlike the end-Cretaceous, the PETM was not a big extinction event but it generated enough environmental disruption to cause a high turnover of land animals, the evolution of ever smaller animals (the “Lilliput effect”), and a mass extinction of tiny shell-making creatures that live on the sea bed (benthic foraminifera).

So what does “relatively rapid onset” mean?

The answer to that question has been an intractable problem for many years, but two new studies have independently just zeroed-in on the answer: 3 to 4 millennia.

More accurately, the two studies have constrained how long it took to release the initial carbon that drove global warming in the PETM – a crucial piece of information if we want to compare the PETM to today’s warming. The first study was presented in December at the AGU conference in San Francisco by Richard Zeebe and co-workers, who have calculated a duration of about 4,000 years or more. The second is a paper by Sandy Kirtland Turner and Andy Ridgwell in Earth and Planetary Science Letters, which was published online the same week, and which calculated that the carbon release took about 3,000 years or less.

Despite the difference, the fact that 2 independent studies, using different data and approaches, arrived at a very similar timescale is a huge advance on previous estimates that could do no better than say the onset of the PETM took somewhere between 5,000 and 20,000 years.

I had the opportunity to chat with both Richard Zeebe and Andy Ridgwell about the PETM at the AGU meeting in December.

Two different approaches

Zeebe et al’s study was sparked by a controversial claim by Wright and Schaller in 2013 that the PETM may have been generated in as little as 13 years, possibly by a comet breaking up in the atmosphere. In a reply to that paper, Zeebe et al showed that it was impossible for the carbon release to generate a signal of ocean warming in such a short period of time.

"...would have to warm the entire planet by 5ºC within 13 years, which is impossible, unless the heat capacity of the ocean is zero, which we know is not the case!"

“The ocean has a heat capacity,” says Zeebe, “and so what happens is that after you release the carbon you get an increased greenhouse effect, the climate system picks up, and you get warming. It would not only have to release the carbon, but would have to warm the entire planet by 5ºC within 13 years, which is impossible, unless the heat capacity of the ocean is zero, which we know is not the case!”

But this also presented Zeebe with an opportunity. The Wright and Schaller study generated very detailed records of variations in the isotopes of carbon and oxygen through the PETM recorded by carbonates in clay sediments from New Jersey, USA.

“We strongly disagree with their interpretation, but we think that the data itself is useful to constrain the timescale of the PETM onset,” says Zeebe. “We have two isotope systems that we can look at. One of those are oxygen isotopes and they are essentially a thermometer, they tell us about climate change. And the other isotope system we’re looking at is carbon isotopes and they tell us something about carbon release.”

“We’ve accompanied these data with climate and carbon cycle modelling. So you take these data records and you try to model them, and you see immediately that if you run the carbon cycle and climate models there are serious problems if you assume the release was extremely fast [eg 13 years], because there’s a big delay between the carbon input signal and the climate response. So what we did with the model is:  stretch the input of the carbon over longer and longer periods of time until we get a match between the observations and the carbon cycle and climate models. In that case we get a consistent story between what is physically possible in terms of the rate of heating of the climate system. As a result, we constrain that the onset of the PETM was probably in the order of 4,000 years.”

Read more...

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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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Daffodils in bloom, the warmest ever December: how worrying is the world’s strange weather?

Posted on 9 February 2016 by Guest Author

December temperatures in London have been warmer than July’s. Scotland is balmier than Barcelona. Artificial snow covers European ski slopes. Africa faces its worst food crisis in a generation as floods and droughts strike vulnerable countries.

With unusual weather from Britain to Australia, scientists are blaming climate change – but also the natural phenomenon called El Niño, which is raising temperatures and disrupting weather patterns. A double whammy then, but how disturbed should we be as the records tumble?

According to the UK Met Office, the exceptional warmth in Britain and northern continental Europe is linked to the strongest El Niño ever recorded. “What we are experiencing is typical of an early winter El Niño effect,” said Adam Scaife, head of Met Office long- range forecasting.

The cyclical event, named after the birth of Christ because it traditionally occurs in Latin America around Christmas, sees temperatures in the equatorial Pacific rise several degrees. The consequences in years like this are dramatic. Monsoons and trade winds are disrupted, leading to cyclones, droughts, floods and food shortages across the world.

Friday night was one of the warmest recorded in the UK in December. With the warm spell due to continue over Christmas, it is almost certain that more records will be broken. According to Scaife, “we cannot attribute the recent floods [in Britain] to the El Niño, but in early winter [during El Niño years] we tend to have a strong jet stream which brings us mild conditions. In late winter, January and February, we tend to get a weak jet stream which brings more wintry conditions.”

Roger Brugge, a senior scientist at Reading University’s atmospheric laboratory, said: “The first 17 days of December have been the mildest on record by a remarkable 1.1C. The average temperature during this period, of 10.6C, is similar to what can be expected around the beginning of May.”

Worldwide, November was the warmest recorded by the US government’s National Oceanic and Atmospheric Administration, and the seventh month in a row where temperatures have been well above the 100-year average; 2015 is on track to be the warmest year and last week the Met Office forecast that the global average temperature in 2016 would be a record 1.14C above pre-industrial temperatures.

Daffodils in bloom at London’s Olympic Park December.

Daffodils in bloom at London’s Olympic Park December. Photograph: Frank Augstein/AP

So is the current spell of exceptional heat around the world a foretaste of life in a warmer climate, or just a temporary blip? Atmospheric scientists believe we are seeing climate change with an El Niño effect on top. The two combined are raising temperatures dramatically.

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8 comments


No climate conspiracy: NOAA temperature adjustments bring data closer to pristine

Posted on 8 February 2016 by dana1981

Congressman Lamar Smith (R-TX) has embarked upon a witch-hunt against climate scientists at NOAA, accusing them of conspiring to fudge global temperature data. However, a new study has found that the adjustments NOAA makes to the raw temperature data bring them closer to measurements from a reference network of pristinely-located temperature stations.

The adjustments are scientifically necessary

Before delving into the new study, it’s worthwhile to revisit the temperature adjustments that Lamar Smith disputes. Volunteers have been logging measurements from weather stations around the world for over 150 years, and climate scientists use that data to estimate the Earth’s average surface temperature. But over a 150-year period, things change, as the authors of this study explain.

Stations have moved to different locations over the past 150 years, most more than once. They have changed instruments from mercury thermometers to electronic sensors, and have changed the time they take temperature measurements from afternoon to morning. Cities have grown up around stations, and some weather stations are not ideally located. All of these issues introduce inconsistencies into the temperature record.

To find out how much actual temperatures have changed, scientists have to filter out these changes in the way the measurements were taken. Those are the adjustments under attack from Lamar Smith. They’re important, scientifically justified, and documented in the peer-reviewed literature.

So what’s the controversy about?

Scientists make adjustments to account for changes in the way both land and ocean temperature measurements have been made over the past 150 years. The ocean adjustments make the biggest difference, and in fact they actually reduce the measured amount of global surface warming over the past century, as compared to the raw data. Thus you would think contrarians like Lamar Smith would appreciate these adjustments; however, over the past couple of decades, they act to very slightly increase the overall global surface warming trend.

raw vs adjusted

NOAA adjusted (green) and raw data (red). The dashed black line shows the difference created by the adjustments. Illustration: Zeke Hausfather

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31 comments


2016 SkS Weekly Digest #6

Posted on 7 February 2016 by John Hartz

SkS Highlights... El Niño Impacts... Toon of the Week... Quote of the Week...  He Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...

SkS Highlights

Industrial-era ocean heat uptake has doubled since 1997 by Rob Painting and Fox News Republican debate moderators asked a climate question! by Dana Nuccitelli (Climate Consensus - the 97%, The Guardian) both attracted the highest number of comments of the aricles posted on SkS during the past week. 

El Niño Impacts

Toon of the Week

 2016 Toon 6

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2016 SkS Weekly News Roundup #6

Posted on 6 February 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Jan 31

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Analysis: How much did El Niño boost global temperature in 2015?

Posted on 5 February 2016 by Guest Author

This is a re-post from Roz Pidcock at Carbon Brief

Almost as soon as the news broke that 2015 was the hottest year in the modern record, the conversation quickly turned to how much of the record-breaking warmth was down to climate change and how much to the Pacific weather phenomenon known as El Niño.

Carbon Brief has spoken to climate scientists working on this question, who all seem to agree El Niño was responsible for somewhere in the region of 10% of the record warmth in 2015.

But while the science seems pretty clear, these numbers got somewhat lost in the media coverage. So, too, did the fact that 2015 was far hotter than the last big El Niño year in 1997 – and that 2015 would still have been a record year even had the El Niño never occurred.

A wide margin

All three of the world’s major meteorological agencies came to the same conclusion last week. NASA, the US National Oceanic and Atmospheric Administration (NOAA) and the UK’s Met Office all confirmed 2015 was the warmest on record and the first year in which global temperature rose 1C above the preindustrial era.

Yesterday, the World Meteorological Organisation – which combines all three agencies’ data into a single definitive statement – agreed that 2015 was a record-breaking year.

As Carbon Brief and many others have noted, it isn’t so much the setting of a new record that is remarkable, but the margin by which 2015 took the top spot.

Combining the three global datasets, global temperature in 2015 was 0.16C above the next warmest year in 2014, a gap the WMO called “strikingly wide”.

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Industrial-era ocean heat uptake has doubled since 1997

Posted on 4 February 2016 by Rob Painting

The oceans are by far the largest heat reservoir in the Earth's climate system, so much so that they make up a whopping 93% of global warming. Thus global warming is really the story of ocean warming. In many blog posts in recent years (see, here, here and here for example) Skeptical Science has consistently drawn attention to the fact that the oceans are continuing to accumulate heat and therefore, despite short-term fluctuations in both surface and atmospheric temperatures, global warming is proceeding largely as anticipated by the scientific community. 

A recent paper, Gleckler et al [2016], manages to put the recent warming of the ocean into a broader, longer-term, perspective. Using ocean temperature measurements obtained from various sources and methods, and utilizing data from the pioneering HMS Challenger expeditions of the late 19th century (Roemmich et al [2012]), the researchers were able to compare the observations stretching back to the mid-1800's with climate model simulations. They found the model simulations were consistent with this diverse collection of ocean temperature data. Perhaps the most startling result of this analysis is just how much the oceans have warmed in recent decades, with the recent acceleration so pronounced that the rate of ocean heat uptake in the industrial-era has doubled since 1997.

Figure 1 - The CMIP5 multi-model mean ocean heat content change from 1865 to 2015 expressed as a percentage for 3 ocean depth layers. The gray bars indicate the 1-standard deviation uncertainty and the black triangles along the bottom denote simulated large volcanic eruptions (which disperse light-scattering sulfate particles). Gray triangles show the many unsimulated small & moderate volcanic eruptions after 2000. Image from Gleckler et al (2016).

Adding greenhouse gases to the atmosphere makes the ocean warmer 

How additional greenhouse gases in the atmosphere cause the ocean to grow warmer is not generally well-known, so it's useful to provide some background context for this new research paper. In a similar vein to the warming of the atmosphere, the warming of the oceans occurs in response to the slowing of heat loss. It works like this: highly energetic solar (shortwave) radiation enters the surface layers and warms the ocean. The overlying air is typically cooler than the sea surface, so some ocean heat is lost to the atmosphere and any surplus is eventually radiated away to space high up in the atmosphere. The amount of heat in the ocean is therefore a balance between solar radiation entering the ocean and the energy which leaves it - mainly through evaporation. The oceans can warm through an increase in solar output (the sun has actually cooled in recent decades, thereby eliminating that as a potential cause) or by reducing the rate of heat loss to the atmosphere. This is where additional atmospheric greenhouse gases come in.

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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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'The Blob' Disrupts What We Think We Know About Climate Change, Oceans Scientist Says

Posted on 2 February 2016 by Guest Author

This is a re-post from DeSmog Canada

Deep in the northeast Pacific Ocean, The Blob is acting strangely.

When the abnormally warm patch of water first appeared in 2013, fascinated scientists watched disrupted weather patterns, from drought in California to almost snowless winters in Alaska and record cold winters in the northeast.

The anomalously warm water, with temperatures three degrees Centigrade above normal, was nicknamed The Blob by U.S climatologist Nick Bond. It stretched over one million square kilometres of the Gulf of Alaska — more than the surface area of B.C. and Alberta combined — stretching down 100-metres into the ocean.

And, over the next two years that patch of water radically affected marine life from herring to whales.

Without the welling-up of cold, nutrient-rich water, there was a dearth of krill, zooplankton and copepods that feed herring, salmon and other species.

The fish out there are malnourished, the whole ecosystem is malnourished,” said Richard Dewey, associate director for science with Ocean Networks Canada, speaking at Shaw Ocean Discovery Centre in Sidney on Thursday.

A change of three degrees is an “extraordinary deviation — something you would expect to happen once in a millennium,” he said.

Pink salmon returned last year, after two years in the ocean, weighing about half their usual weight, sea lion pups, seabirds and baleen whales had difficulty finding adequate food, but jellyfish thrived.

Now, after more than two years of disruption to marine ecosystems, it looks as if The Blob is dissipating, said Dewey, who has studied the phenomenon since it appeared.

Cold winter storms, that have been absent for almost three years allowing the anomaly to develop, swept across the Gulf of Alaska in November and December, finally dispersing the warm surface waters.

But, as oceanographers try to predict what will happen next, Dewey believes it is too early to pronounce the death of The Blob.

The Blob as captured in NOAA imaging in 2014. 

It’s not dead yet. I think there’s a lot of heat out there, deep down,” he said.

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Fox News Republican debate moderators asked a climate question!

Posted on 1 February 2016 by dana1981

In the 2016 Republican presidential candidate debates, climate change has rarely been discussed. In last Thursday’s debate, the last before tonight’s Iowa caucus votes, on Fox News of all networks, there was one brief climate question directed at Senator Marco Rubio (R-FL). Unfortunately it was framed as a ‘gotcha, flip-flop’ question, with Rubio asked about his apparent support 8 years ago for a carbon cap and trade system in Florida, versus his current opposition to the concept.Rubio responded:

I have never supported cap and trade and I never thought it was a good idea. And I was clear about that at the time.

And I do not believe it’s a good idea now. I do not believe that we have to destroy our economy in order to protect our environment. And especially what these programs are asking us to pass that will do nothing to help the environment, but will be devastating for our economy.

When I am president of the United States of America, there will never be any cap-and-trade in the United States.

In another debate 4 months ago on CNN, Rubio made similar comments, adding:

America’s a lot of things, the greatest country in the world, but America is not a planet. And we are not even the largest carbon producer anymore, China is, and they are drilling a hole anywhere in the world that they can get ahold of.

Fact checking Marco Rubio

Politifact ruled it “mostly true” that Rubio never supported cap and trade. However, the rest of his comments are mostly false.

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6 comments


2016 SkS Weekly Digest #5

Posted on 31 January 2016 by John Hartz

SkS Highlights... El Niño Impacts... Toon of the Week... Quote of the Week... They Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...

SkS Highlights

Record hot 2015 gave us a glimpse at the future of global warming by Dana Nuccitelli (Climate Consensus - the 97%, The Guardian) garnered the highest number of comments of the articles posted on SkS during the past week. Climate scientists' open letter to the Wall Street Journal on its snow job by Emmanuel Vincent & Daniel Nethery (Climate Feedback) attracted the second highest number.

El Niño Impacts

Global temperatures will continue to soar over the next 12 months as rising levels of greenhouse gas emissions and El Niño combine to bring more record-breaking warmth to the planet.

According to the Met Office’s forecast for the next five years, 2016 is likely to be the warmest since records began. Then in 2017 there will be a dip as the effects of El Niño dissipate and there is some planet-wide cooling.

But after that, and for the remaining three years of the decade, the world will continue to experience even more warming. The forecast, which will be released this week, is the first such report that the Met Office has issued since it overhauled its near-term climate prediction system last year. 

Here is the weather forecast for the next five years: even hotter by Robin McKie, The Guardian, Jan 30. 2016

Severe El Niño-linked drought has destroyed crops, killed farm animals and dried up water sources across East Asia and the Pacific, aid workers said, and UNICEF appealed for $62 million to assist children impacted by various crises in the region.

Humanitarian agencies are monitoring and responding to droughts and food insecurity in an area from Indonesia and the Philippines, southeast to Papua New Guinea and the Pacific Islands.

"El Niño is peaking at the moment, and we expect the impacts to come up after the peak," said Krishna Krishnamurthy, a regional climate risk analyst for the World Food Programme.

El Niño parches Asia Pacific, destroying crops and drying up water sources by Alisa Tang, Thomson Reuters Foundation, Jan 26, 2016

Toon of the Week

 2016 Toon 5

Hat tip to I Heart Climate Scientists

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2016 SkS Weekly News Roundup #5

Posted on 30 January 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Jan 24

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1 comments


'If the world ends in 2100, we’re probably OK'

Posted on 29 January 2016 by howardlee

There’s a myopia in the climate discourse today.

“Everyone is focused on what happens by 2100. But that’s only 2 generations from today. It’s like: If the world ends in 2100 we’re probably OK!” says Professor Richard Zeebe of the University of Hawai’i. “But It’s very clear that over a longer timescale there will be much bigger changes.”

If the next century seems impossibly far off, bear in mind that if you have a young child now, we’re talking about the world her or his grandchildren will be trying to raise their kids in.

Scientists who take the long view on climate change see parallels between global warming today and mass extinctions in Earth’s past: “Apart from the stupid space rock hitting the Earth, most mass extinctions were CO2-driven global warming things,” says Professor Andy Ridgwell of Bristol University in the UK.

It has been a consistent pattern throughout geological time: “If you screw with the climate enough, you have huge extinctions,” says Ridgwell.

So much of what you read and hear about climate change is heavily based on instrument records that only go back 160 years or so. But Richard Zeebe and Andy Ridgwell are among a few scientists who look millions of years into Earth’s past to learn how the Earth responded to big additions of CO2 into the atmosphere before. I had the opportunity to chat with each of them about their work during the American Geophysical Union conference in San Francisco at the end of last year.

Beyond the ice ages

It’s true that scientists can learn about the ice age climate going back 800,000 years from bubbles of air trapped in ancient ice drilled from Greenland and Antarctica. They reveal many swings from warm to cold to warm again, in a low-CO2 world mostly cooler than today. “We went from very cold and low sea level to a mild climate with normal sea level,” says Ridgwell. But it was a very different scenario than today - those cycles were mainly driven by Earth’s wobbles as it circles the Sun, and those same orbital wobbles mean we should be cooling, not warming, today.

So both Ridgwell and Zeebe have been studying the best equivalent to modern climate change they have found so far, a relatively rapid global warming event that occurred 56 million years ago, called the “Paleocene-Eocene Thermal Maximum,” mercifully shortened to “PETM.” For Ridgwell, it’s a better analog for the future: 

This is why I like the PETM, at least it’s a warming event. It had a peak global warming of about 5º or 6ºC, which is a little bit beyond the end-of-the-century worst case scenario.

For Zeebe it’s also about data quality: 

We are focusing on the PETM is because we have relatively good sediment records. We are able to constrain timescales and ages relatively accurately. If you go further back in time, these constrains become very, very difficult.

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8 comments


Climate scientists' open letter to the Wall Street Journal on its snow job

Posted on 28 January 2016 by Guest Author

This is a guest post from Emmanuel Vincent and Daniel Nethery for Climate Feedback (@ClimateFdbk)

An opinion piece by Patrick Michaels in the Wall Street Journal (“The Climate Snow Job,” Jan. 24, 2016) is riddled with inaccuracies, according to an evaluation by ten scientists with relevant expertise.

The article makes false or misleading statements on several aspects of climate science, including the global temperature record, the methodology for measuring global temperature, the effect of El Niño on global temperature, and the economic impact of climate change. The mention of so many distinct aspects of climate science is intended to allow the author to pass himself off as an authority on climate science, while at the same time bamboozling readers into accepting three startlingly spurious claims.

Claim 1: “It is therefore probably prudent to cut by 50% the modelled temperature forecasts for the rest of this century.”

This is the opinion of the author with no basis in science. Climate models have successfully projected changes in climate observed in recent years. These models are not perfect representations of our climate system, but they are our best tool for forecasting future climate change.

Claim 2: “The notion that world-wide weather is becoming more extreme is just that: a notion, or a testable hypothesis.”

The scientific consensus is that some extreme weather events are becoming more severe and occurring with greater frequency in relation with climate change and more importantly these are expected to increasingly affect societies in the future. The author attempts to cast doubt on the science by claiming that the economic cost of extreme weather has remained stable over the past quarter-century. The author misleads the reader into concluding that because the economic cost of extreme weather has not increased, then extreme weather cannot have increased. But this fallacious reasoning is only the tip of the iceberg. Dr Laurens Bouwer, a senior risk analysis advisor at Deltares, told Climate Feedback that the claim that losses caused by severe weather have remained stable over the past 25 years is “not accurate”. It also belies the extent to which insurance agencies recognize the risks that climate change poses. The article cites data from Munich Re, whose head of Geo Risks Research and its Corporate Climate Centre, Professor Peter Höppe, has publicly stated that “climate change is one of the greatest risks facing humankind this century. Through a part of its core business, the insurance industry is directly affected and therefore assumes a leading role in devising solutions for climate protection and adaptation to the inevitable changes.”

Claim 3: “Without El Niño, temperatures in 2015 would have been typical of the post-1998 regime.”

This is false. Scientists estimate that the current El Niño event contributed only a few tenths of a degree to the record global temperature observed in 2015. The year would have gone down as the hottest on record even without the El Niño event, as explained in this article by The Carbon Brief.

Patrick J. Michaels would have his readers believe that the observed increase in global temperature, underlined by the news of the hottest year on record, is “business as usual”. His readers should instead draw the conclusion that no matter how conclusive the evidence, climate contrarians like Michaels intend to go about their “business as usual”, casting doubt on the science.

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The science for climate change only feeds the denial: how do you beat that?

Posted on 27 January 2016 by John Cook

The ConversationAs the scientific consensus for climate change has strengthened over the past decade, the arguments against the science of climate change have been on the increase.

That’s the surprise finding of a study, published in the journal Global Environmental Change last month, which analysed and identified the key themes in more than 16,000 publications about climate change by conservative organisations.

Conservative think-tanks are organisations that oppose policies, such as regulation of pollution by the fossil fuel industry (some have also opposed regulation of the tobacco industry in the past and, in fact, some continue to do so today).

One study found that from 1972 to 2005, over 92% of climate contrarian books originated from conservative think-tanks. They are often ground zero for misinformation casting doubt on climate science, with their messages spread by contrarian blogs, conservative media and politicians opposing climate policy.

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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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Tracking the 2°C Limit - December 2015

Posted on 26 January 2016 by Rob Honeycutt

Holy frijole!

Okay, I'm not surprised that December beat November as the warmest anomaly in the entire GISS temperature record, but I was taken a little aback by how much. 

For a full size image click here.

One thing I note from this graph is the consistency between the peak (assuming we're likely near the peak of the surface warming due to the current super El Nino) and previous El Nino peaks in the GISS data. You essentially find the same trend as the trend in the full data set. Same follows for La Nina periods as well.

Many contrarians hold to the false notion that the current warming is "just" a function of the El Nino, whereas the current anomalies are clearly fully consistent with the long term rising trend is surface temperatures.

I'm also continuing to track the Ocean Nino Index (ONI) for this El Nino against the 1997/98 El Nino, and the ONI data is continuing on track. The ONI data goes all the way back to 1950 and the current 2.3 figure ties with 1997/98 as the highest in the entire data set. We will see next month if this El Nino breaks that record. Click here for a larger version of the graph below.

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