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Latest Posts


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?


New research quantifies what's causing sea level to rise

Posted on 30 October 2014 by John Abraham

There have been a number of studies that have come out recently on ocean warming and sea-level rise. Collectively, they are helping scientists coalesce around an emerging understanding of climate change and its impact on the Earth. Most recently, a study by scientists Sarah Purkey, Gregory Johnson, and Don Chambers was published. This team was responsible for a 2010 paper that was groundbreaking in that it quantified very deep (abyssal) sea warming. This latest paper is, in some respects, a continuation of that work.

The researchers recognized that changes to the sea levels are mainly caused by thermal expansion of ocean waters as they heat, changes to the saltiness of water, and by an increase in ocean waters as ice melts and flows into the sea. The total annual sea level rise is about 3 mm per year – the question is, how much of that is from expansion and how much is from melting?

Greg Johnson Greg Johnson

The researchers used a few tools to answer this question. One tool was ocean bottom pressure measurements. If you can measure changes to ocean pressure, you can deduce how much water is in the ocean. Another tool is through an inventory approach. This inventory method quantifies how much glaciers retreat, polar ice melts, and changes to water storage on land. The paper reports that both methods agree with each other. They conclude that increased water in the oceans is causing about 1.5–1.8 mm per year of sea level rise. The actual value depends, in part, on which years are under consideration.

The authors don’t just consider the ocean as a whole. They break the ocean regions into seven different sections. The reason for this subdivision is that the change to ocean levels is not uniform. In some reasons, waters are rising quickly, in other regions, the rise is much slower or zero. One region for regional variability is that the Earth’s gravity is changing.

For instance, there is so much ice in Greenland and Antarctica that is melting and flowing into the ocean, the mass of these two regions is being reduced; therefore, the pull of gravity toward Greenland and Antarctica is changing. As a result, we expect water levels near Greenland and Antarctica may actually fall as those ice sheets melt.



2014 SkS Weekly News Roundup #44A

Posted on 29 October 2014 by John Hartz

A chronicler of warnings denied

Naomi Oreskes is a historian of science at Harvard, but she is attracting wide notice these days for a work of science fiction.

“The Collapse of Western Civilization: A View From the Future,” written with Erik M. Conway, takes the point of view of a historian in 2393 explaining how “the Great Collapse of 2093” occurred.

“Without spoiling the story,” she told me, “I can tell you that a lot of what happens — floods, droughts, mass migrations, the end of humanity in Africa and Australia — is the result of inaction to very clear warnings” about climate change caused by humans. The 104-page book was listed last week as the No. 1 environmental best-seller on Amazon. Dr. Oreskes, 55, spoke with me for two hours at her home in Concord, Mass., and later again by telephone. Here is an edited and condensed version of the conversations.

A chronicler of warnings denied by 



Republican politicians aren't climate scientists or responsible leaders

Posted on 28 October 2014 by dana1981

Republican Senate Minority Leader Mitch McConnell is hoping to become the Senate Majority Leader after the forthcoming election on November 4th, although despite hailing from conservative Kentucky, McConnell is in a very tight race. The Cincinnati Enquirer editorial board recently had a long discussion with McConnell and tried to pin him down on the subject of global warming.

McConnell wouldn’t directly answer whether he believes in climate change.

Enquirer’s editorial board volleyed several questions about what it would take to convince him of climate change. He turned the subject every time to jobs. McConnell said he believes imposing regulations to reduce greenhouse gases blamed for climate change would only hurt America and not mitigate what other countries, such as China, are doing...

“We can debate this forever,” McConnell said. “George Will had a column in the last year or so pointing out that in the 70s, we were concerned the ice age was coming. I’m not a scientist. I’m interested in protecting Kentucky’s economy.”

Leaving aside McConnell’s reference to the 1970s ice age myth, the cop-out about not being a scientist is a strange and dangerous one.



The role of the ocean in tempering global surface warming

Posted on 27 October 2014 by Guest Author

This is a re-post of an article by Richard Allan for NOAA

It is well known that the surface has warmed over the past few decades, primarily in response to rising concentrations of greenhouse gases. ENSO variability and other natural factors, have additionally contributed toward year-to-year fluctuations about this warming trend (dark red line in Figure 1). Strong El Niño events add a few tenths of a degree Celsius to the global average surface temperatures. However, there has recently been an observed slowing in the rate of surface warming (compare the red and orange trend lines in Figure 1) which may be related in part to a greater number of cold La Niña events in the 2000s compared to previous decades (see article by


Figure 1: Observed changes in global annual average surface temperature relative to 1961-1990 from the HadCRUTv4 dataset which is updated to account for gaps in data coverage (version 2.0 Long Reconstruction). The temperature difference is compared with 1961-1990 average using data from Cowtan & Way (2014). The rate of warming from 1970-2013 (red trend line) is larger than the rate of warming between 1998-2013 (orange line).



2014 SkS Weekly Digest #43

Posted on 26 October 2014 by John Hartz

SkS Highlights

John Abraham's Another global warming contrarian paper found to be unrealistic and inaccurate garnered the most comments of the srticles posted on SkS during the past week. If you have not already checked it out, you will want to do so. Dr. John Abraham is a Professor of Thermal Sciences where he researches in climate monitoring and renewable energy generation for the developing world. His energy development work has extended to Africa, South America, and Asia. He partners with Dana Nuccitelli in the production of the blog, Climate Consensus - The 97 % hosted by The Guardian 

Poster of the Week

 2014 Poster 43 

Quote of the Week

Thus, a new global average temperature record in 2014 would be all the more extraordinary. So will it happen? "As we watch daily temperature results come in, it’s becoming ever more likely," says John Abraham, a climate scientist at the University of St. Thomas in Minnesota who studies ocean warming and climate change. Abraham emphasizes, though, that there are several other global agencies besides NOAA (including our own NASA) that also track temperatures and they don't always perfectly agree on the ranking of record years.

"We may break the all-time temperature record without having an El Nino," adds Abraham. "Which means that the Earth shouldn’t be warm this year." 

Climate records are breaking so often now, we’ve stopped paying attention by Chris Mooney, Wonkblog, Washington Post, Oct 21, 2014

SkS in the News

Richard Allan referenced a Pacific Ocean warming post by Rob Painting in an excellent summary of ocean warming research for NOAA.

NewsMax used SkS to debunk the 'Antarctic ice is growing' myth.

SciLogs referenced The Debunking Handbook

SkS Spotlights

97 Hours: Jason Box

Jason Box's bio page

Coming Soon on SkS

  • Republican politicians aren't climate scientists, but usually defer to the experts (Dana)
  • Climate Models Anticipated Human-Caused Warming in the North Pacific (Rob Painting)
  • Satellites may have underestimated atmosphere warming by 30% (John Abraham)
  • Forget ‘saving the Earth’ – it’s an angry beast that we’ve awoken (Clive Hamilton)

Toon of the Week

 2014 Toon 43

h/t to I Heart Climate Scientists



2014 SkS Weekly News Roundup #43B

Posted on 25 October 2014 by John Hartz

Recently discovered microbe is key player in climate change

As permafrost soils thaw under the influence of global warming, communities of soil microbes act as potent amplifiers of global climate change, an international study has shown.

Tiny  are among the world's biggest potential amplifiers of human-caused climate change, but whether microbial communities are mere slaves to their environment or influential actors in their own right is an open question. Now, research by an international team of scientists from the U.S., Sweden and Australia, led by University of Arizona scientists, shows that a single species of microbe, discovered only very recently, is an unexpected key player in climate change.

The findings, published in the journal Nature, should help scientists improve their simulations of future climate by replacing assumptions about the different  emitted from thawing permafrost with new understanding of how different communities of microbes control the release of these gases.

Recently discovered microbe is key player in climate change,, Oct 22, 2014



2014 SkS Weekly News Roundup #43A

Posted on 24 October 2014 by John Hartz

Amazon deforestation picking up pace, satellite data reveals

The deforestation of the Brazilian Amazon has accelerated rapidly in the past two months, underscoring the shortcomings of the government’s environmental policies.

Satellite data indicates a 190% surge in land clearance in August and September compared with the same period last year as loggers and farmers exploit loopholes in regulations that are designed to protect the world’s largest forest.

Figures released by Imazon , a Brazilian nonprofit research organisation, show that 402 square kilometres – more than six times the area of the island of Manhattan – was cleared in September.

Amazon deforestation picking up pace, satellite data reveals by Jonathan Watts, The Guardian, Oct 19, 2014



2014 Arctic sea ice extent - 6th lowest in millennia

Posted on 23 October 2014 by dana1981

The National Snow and Ice Data Center has reported that this year we saw the 6th-lowest minimum Arctic sea ice extent on record. Research has shown that most of the long-term decline in sea ice, or the “death spiral” as it’s come to be known, is due to human-caused global warming.

Natural factors play a role in the extent of the Arctic sea ice as well, especially changes in weather conditions on a year-to-year basis. For example, 2012 shattered the previous record low Arctic sea ice extent because on top of the human influences, the weather conditions were ripe for a dramatic decline that year. In 2013 and 2014, weather conditions were closer to normal, so they didn’t break the 2012 record. As a result, the usual suspects have declared that Arctic sea ice is now “expanded” compared to 2 years ago.

The flaw in that argument is illustrated in this animated graphic I created.

sea ice escalator

September Arctic sea ice extent data since 1980 from the National Snow and Ice Data Center (blue diamonds).  "Recovery" years, meaning years when the sea ice extent is greater than the previous year, are highlighted in red to mock the repeated cynical claims of climate change "skeptics" that global warming has somehow stopped.



Scientists to Explain 'Climate at Your Doorstep' at New Online Hub

Posted on 22 October 2014 by Guest Author

This is a re-post from Inside Climate News

While the climate community was fixed on global climate negotiations unfolding at the UN last week, one news organization was focused on educating people about the local damage that's already resulted from the world's inaction.

On Sept. 22, the online newsroom The Daily Climate launched a Kickstarter to raise $25,628 for "Climate at Your Doorstep." The project aims to build an online community of scientists, journalists and members of the public to discuss how climate impacts are already affecting people around the country and the world.

Organized around the hashtag #climatedoorstep, people will post questions, photos and observations on social media. The hash-tagged content will feed into a Daily Climate web page, and a panel of eight appointed scientific experts will respond to comments and questions.

The panelists include academic scientists, such as Katharine Hayhoe of Texas Tech University and Marshall Shepherd at the University of Georgia, and TV meteorologist Jim Gandy.



Another global warming contrarian paper found to be unrealistic and inaccurate

Posted on 21 October 2014 by John Abraham

It’s hard to find a reputable scientist who denies that human emissions of greenhouse gases are warming the planet and that there will be consequences for human society and the biological health of the planet. There are a few holdouts who, for various reasons, either think humans are not causing warming or that the warming will not have much consequence.

Some members of this vocal minority spend a lot of time trying to convince the public that they are right. They write letters to newspapers, appear in slick movies, give press conferences, promote their views to Congress, and so on. Their high profile gives the public a false sense that there are two relatively equal-sized bodies of experts that cannot agree on climate change; this is not true.

An even smaller subset also tries to publish their views in the scientific literature – the dueling ground for experts. Sometimes these contributions have been useful, adding some nuance to the discussion, but all too often they have proven to be of very poor quality when other scientists have had a chance to dissect them.

A few months ago, I co-authored an article which charted the different quality in scientific output from the Dwindling Few contrarians compared to the majority of experts. My colleague, Dana Nuccitelli, summarized the article here. What we show is that the Dwindling Few have had a very poor track record – having papers rebutted time after time after time because of errors they have made. The low quality of their research has caused journal editors resign, and they have wasted the time of their colleagues who have had to publish the rebuttals to their work.



From Pole to Pole - a climate-themed tour through a zoo

Posted on 20 October 2014 by BaerbelW

The Wilhelma is Stuttgart’s zoological and botanical garden and is one of the many participants in the Pole to Pole campaign organised by the European Association of Zoos and Aquaria (EAZA) which represents and links 345 institutions and organisations in 41 countries. The European zoos count millions of visitors each year and EAZA aims to educate as many of them as possible about environmental and conservation issues in countries around the world. Previous campaigns highlighted the plights of tigers, rhinosapes or European carnivores to name just a few examples. Participation of the zoos and what they offer in support of a campaign is voluntary and it usually hinges on whether or not a zoo keeps any of the flagship-species highlighted in a campaign.

EAZA-Logo WilhelmaLogoP2P-small



2014 SkS Weekly Digest #42

Posted on 19 October 2014 by John Hartz

SkS Highlights

Another "lightening rod" article by Dana, Dinner with global warming contrarians, disaster for dessert, drew the highest number of comments of the articles posted on SkS during the past week.

If you have not already done so, be sure to check out Rob Paining's original SkS article, Ocean Warming has been Greatly Underestimated. It's a real "eye opener".

Toon of the Week

2014 Toon 42

h/t to I Heart Climate Scientists



2014 SkS Weekly News Roundup #42B

Posted on 18 October 2014 by John Hartz

As deaths mount in Nepal disasters, questions about climate change raised

October is not typically the month for avalanches in Nepal. It is also not the time for blizzards. The fall month usually means clear skies and sunshine in the Himalayan country when thousands of foreigners climb its tall mountains.

Hikers were doing exactly that earlier this week when an avalanche and blizzard struck, killing at least 26 people, including four Canadians.

Still missing are 100 more trekkers. According to a Facebook page set up, there may be up to 32 Canadians whose family members have not been able to reach them since the avalanche struck.

As deaths mount in Nepal disasters, questions about climate change raised by Raveena Aulakh Environment and Allan Woods, Toronto Star, Oct 15, 2014



Why ice sheets will keep melting for centuries to come

Posted on 17 October 2014 by Guest Author

This article was originally published on The Conversation [UK] on Sep 26, 2014.

The Conservation Logo

Why ice sheets will keep melting for centuries to come

By Eelco Rohling, University of Southampton

Antarctic Ice Sheet

It may already be too late to stop Antarctic ice sliding into the ocean. EPA

Ice sheets respond slowly to changes in climate, because they are so massive that they themselves dominate the climate conditions over and around them. But once they start flowing faster towards the shore and melting into the ocean the process takes centuries to reverse. Ice sheets are nature’s freight trains: tough to start moving, even harder to stop.

We know this process has been going back and forth throughout history – it’s why we’ve had ice ages and warm periods. But until now we haven’t known exactly how quickly ice sheets retreated and reformed. New research published in the journal Nature Communications gives us an answer, and it isn’t great news.

It turns out sea levels often rose at scary rates in response to natural climate changes, long before mankind began pumping carbon into the atmosphere.

In the short-term sea level is affected by ocean warming and so-called “thermal expansion”, or melting glaciers based on land. These changes can occur quickly – within a decade – but their impact on sea level is relatively small, in the tens of centimetres. The drivers of longer-term sea level rise, over decades or centuries, are the continental ice sheets of Greenland and Antarctica.

On the fringes of these ice sheets are “ice shelves” stretching far out into the ocean. Ice shelves can be hundreds of meters thick and, because 90% of ice in water floats below the surface, they remain “grounded” on the sea floor as long as the sea is less deep than 90% of the ice shelf thickness. Where the sea floor is deeper or the ice shelf gets thinner, there will be an area of floating land ice; here, warming ocean water can get underneath and melt the ice. Once sufficiently destabilised, an ice shelf can break up catastrophically.

ice shelf

One small portion of the West Antarctic ice shelf slides into the sea. Images via NASA



2014 SkS Weekly News Roundup #42A

Posted on 16 October 2014 by John Hartz

15 years from now, our impact on regional sea level will be clear

Human activity is driving sea levels higher. Australia’s seas are likely to rise by around 70 centimetres by 2100 if nothing is done to combat climate change. But 2100 can seem a long way off.

At the moment, regional sea-level rise driven by warming oceans and melting ice is hidden by natural variability such as the El Niño, which causes year-to-year changes in sea level of several centimetres.

So at any particular place, the sea level might go up in one year, and down in the next. On Australia’s northwest coast, for example, the sea level was three centimetres below normal during 1998, but four centimetres above normal the following year.

At the same time, human-caused climate change is driving sea level relentlessly upwards in most regions, eventually pushing it far outside the bounds of historical variation. But when will the difference become clear?

15 years from now, our impact on regional sea level will be clear by John Church and Xuebin Zhang, The Conversation AU, Oct 12, 2014



Scientist in focus – Arctic adventurer Will Steger

Posted on 15 October 2014 by John Abraham

As readers know, I often focus on the story, and history, of someone who makes an impact in climate change. This is the third such article and I think you will agree, it shows that it isn’t just lab scientists and academics that are shaping the conversation about climate change.

Will Steger really rose to prominence as he led ventures to explore the polar regions of our planet. But those adventures were years in the making; they began in his childhood. Will was one of nine kids raised by parents who encouraged exploration. As long as Will stayed out of trouble and succeeded in school, he had very few limits placed on his activities. In 1957 when Will was 13, he would document meteorological activity in journals at night as part of the International Geophysical Year, in addition to nature drawings of close up flowers and other aspects of the natural world. By 15, he was inspired by adventures of Huck Finn and his National Geographic magazines to travel with his brother down the Mississippi River. It was his first (and last) motorized expedition.

In college, Will fell in love with geology and begin to explore the world more seriously. He graduated with a B.S. degree and began a teaching career which included climate change. But, it was in the wilderness that he began to make his mark.

It was Will’s early observation of the natural world and his curiosity of weather and climate that eventually enabled him to explore and survive in the Arctic. It is likely that no one has more first-hand experience in the Arctic and Antarctic than Will. He has traveled tens of thousands of miles by kayak and dogsled – leading teams on some of the most significant polar explorations our world has ever known. He was awarded the Lifetime Achievement Award from National Geographic Magazine, the inspiration from his childhood, in 2007.

Will Steger joined Amelia Earhart, Robert Peary and Roald Amundsen in receiving the National Geographic Society’s prestigious John Oliver La Gorce Medal in 1995 for Accomplishments in Geographic Exploration, Accomplishments in the Sciences, and Accomplishments in Public Service to Advance International Understanding. This was the first time the Society presented these three categories together and this award has not been given since.

Will Steger Will Steger

Among his accomplishments are the first confirmed dogsled journal to the North Pole without resupply (1986), the longest unsupported dogsled expedition in history (1600 mile traverse of Greenland in 1988), the first dogsled traverse of Antarctica (3471 miles in 1989-1990), and the first dogsled traverse of the Arctic Ocean in one season (1995).



Ocean Warming has been Greatly Underestimated

Posted on 14 October 2014 by Rob Painting

Key Points:
  • The oceans are by far the largest heat reservoir on Earth, absorbing 93% of global warming. Because of this, accurate assessments of heat uptake are essential to balance the sea level budget, and for observationally-based estimates of climate sensitivity.     
  • Prior to 2005, when the Argo global array of submersible floats became operational, ocean temperature was much more sparsely sampled, especially in the southern hemisphere, leading to larger uncertainty over the evolution of ocean warming through time.
  • Durack et al (2014) analyse the period from 1970-2004 combining ocean temperature and sea surface height measurements with climate model simulations, and find that sparse sampling in the southern hemisphere oceans, and limitations of previous analytical methods, has led to a substantial underestimate of warming in the 0-700 metre layer*.
  • When corrected for this bias, Durack (2014) find that the top 700 metre layer of ocean, over the period 1970-2004, has warmed some 24-58% more than previous analyses have indicated. 

Figure 1 - Observed (coloured bars) and modelled (grey bars) upper ocean heat content changes for the period 1970-2004 from previous analyses. Top coloured segments are the adjustments based on the Durack (2014) study. Units are x1022 joules 35 yr-1 and MMM = multi model mean. Image adapted from Durack et al (2014). 

The Oceans Have Warmed, But How Much?

The Argo system of automated floats was constructed in order to provide more reliable and robust measurements of ocean temperature, and other quantities such as salinity and current velocity. Although they only measure down to typical depths of 2000 metres, and still exclude regions such as the Arctic and Indonesian Throughflow, the 3000+ floats represent a major step up in accuracy over older methods.

Figure 2 - typical Argo cycle.



Dinner with global warming contrarians, disaster for dessert

Posted on 13 October 2014 by dana1981

Twelve climate scientists and contrarians recently had dinner together in the UK, which for some reason received media attention. While everyone should be free to have dinner with whomever they like, the problem with this particular event was that the ensuing media coverage made the contrarians seem downright reasonable. For example, the article about the dinner stated,

“...the insults slung around online only hinder the process of rational scientific debate.”

Yet one of the contrarians attending the dinner was Anthony Watts, who runs a blog that regularly insults climate scientists and climate realists. In fact, just a few days after the dinner, Watts was already taunting Ben Santer, one of the world’s most highly respected climate scientists, who had previously treated Watts with courtesy and respect. The article also quoted Watts as saying,

We’ve been at odds so long, it is time to present science together,

Climate contrarians are already free to present science at climate conferences. For example, the annual American Geophysical Union (AGU) fall meeting is the largest gathering of climate scientists presenting and discussing their research. Every year, the vast majority of scientific research presented at the AGU conference and others like it (about 97% or so) is consistent with the expert consensus on human-caused global warming. Contrarians don’t present science there because they have so little science to present.

The Mail on Sunday’s David Rose also attended the dinner. His latest climate article focused on the slight increase in Arctic sea ice as compared to the record low of two years ago (and of course on Al Gore), while ignoring the fact that the Arctic has lost about 70% of its total volume of sea ice over the past three decades.



2014 SkS Weekly Digest #41

Posted on 12 October 2014 by John Hartz

SkS Highlights

Howard Lee's original SkS article, The long hot tail of global warming - new thinking on the Eocene greenhouse climate, generated the most comments of the articles posted on SkS during the past week. 

El Niño Watch

"In their monthly update, scientists at the National Oceanic and Atmospheric Administration’s Climate Prediction Center and the International Research Institute for Climate and Society at Columbia University said there is still a two-thirds chance that a weak El Niño event emerges and that it will likely do so in the October-to-December timeframe, lasting until spring 2015."

Where Is El Nino? And Why Do We Care? by Andrea Thompson, Climate Central, Oct 9, 2014 

Toon of the Week


h/t to I Heart Climate Scientists



2014 SkS Weekly News Roundup #41B

Posted on 11 October 2014 by John Hartz

40% drop in solar PV cost is brightest spot of global epergy picture

In a world wrestling with climate change and the need to phase out fossil fuels, nothing is more critical than making sure there are reliable and cost-effective clean energy technologies ready to fill the void.

Keeping track of the pitfalls and possibilities is the Paris-basedInternational Energy Agency, an autonomous organization that has been analyzing energy for 40 years. In 2006, the influential agency began publishing Energy Technology Perspectives, a report that examines energy technologies and their potential for transforming the way the world uses power.

Because the agency is viewed as being above the fray of climate change politics, the ETP's detailed technology reports have become a must-read for policymakers and anyone else seeking guidance on what's possible and what's not in clean energy. The reports influence the UN climate treaty negotiations—talks meant to produce a climate accord in Paris late next year.

40% Drop in Solar PV Cost is Brightest Spot of Global Energy Picture by Elizabeth Douglass, InsideClimate News, Oct 10, 2014



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