Collapse of Arctic sea ice

News that Russian scientist had to evacuate a scientific research station based on an ice floe – North Pole-40 –  is another sign of how climate change is influencing the Arctic (see Floating research station in need of evacuation). The researchers had intended to stay until September but the floe started to break up earlier this month.

This short video from Climate Denial Crock of the Week illustrates how Arctic ice has decreased over the period 1979 – 2012.

Arctic Sea Ice Collapse 1979-2012 (PIOMAS)

Thanks to Arctic 2013.

See also: The Making of a Classic Climate Graph

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Agreement polar ice sheets are melting

Many climate scientists felt the conclusions on effects of global warming in the 2007 IPCC review were too conservative. One reason was the estimation of likely melting of ice sheets and its effects.

Problem was that there was insufficient knowledge to draw definite conclusions. And the measurements of changes in ice sheets just wasn’t accurate enough.

That’s now changed and a large number of experts agree global warming has caused loss of ice from these ice sheets. And this has contributed to measured increases in sea level.

Richard A. Kerr reports in Science (see Experts Agree Global Warming Is Melting the World Rapidly):

“Forty-seven glaciologists have arrived at a community consensus over all the data on what the past century’s warming has done to the great ice sheets: a current annual loss of 344 billion tons of glacial ice, accounting for 20% of current sea level rise. Greenland’s share—about 263 billion tons—is roughly what most researchers expected, but Antarctica’s represents the first agreement on a rate that had ranged from a far larger loss to an actual gain. The new analysis, published on page 1183 of this week’s issue of Science, also makes it clear that losses from Greenland and West Antarctica have been accelerating, showing that some ice sheets are disconcertingly sensitive to warming.”

He’s referring to the major paper by Andrew Shepperd and others, A Reconciled Estimate of Ice-Sheet Mass Balance.

Over recent years climate change deniers/contrarians/sceptics have cherry picked data to counter any suggestion that the earth’s large ice sheets are melting. They have pointed to increased amounts of ice in Eastern Antarctica to balance reports of massive losses of ice in the Arctic. (Have a look at this animation to see how such data can be cherry picked). Similarly they have tried to hide concern of the loss of land ice by stressing reports of local increases in sea ice.

But the paper by Shepperd et al. combined data from satellite altimetry, interferometry, and gravimetry measurements. This provides more reliable estimates of changes in the ice sheets, and gives some detail of these changes. This figure from the paper gives an idea of the detail of their findings. It shows that all the major regions of the polar ice sheets except one (East Antarctica) have lost mass since 1992. The authors also estimate that mass loss from the polar ice sheets has contributed roughly 20 percent of the total global sea level rise during that period (at a rate of 0.59 ± 0.20 millimeter year⁻¹ ).

Figure S1 from Shepperd et al.: Cumulative ice mass change of West Antarctica ((WAIS) East Antarctica (EAIS), Greenland (GrIS), and the Antarctic Peninsula (APIS).

And to underline the fact that denier claims of amounts of ice increasing in Antarctica are false, NASA recently displayed this figure showing data from Antarctica from their satellite measurements

Monthly changes in Antarctic ice mass, in gigatones, as measured by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites from 2003 to 2011. Image credit: NASA-JPL/Caltech; NASA GSFC; CU-Boulder; Technical University of Munich; Technical University of Denmark; Delft University of Technology, Aerospace Engineering, Netherlands; Durham University, UK; Leeds University, UK

Could those climate change deniers/contrarians/sceptics please stop hiding behind claims that gains by Antarctic ice sheets balance losses from ice sheets in Greenland and the Arctic.

They don’t.

See also:
Science: Major Regions of Polar Ice Have Been Shrinking Since 1992
Polar Ice Sheets Losing Mass, Several Methods Show
New Study Shows Global Warming Is Rapidly Melting Ice at Both Poles
Human-Caused Climate Change Signal Emerges from the Noise
Study: Polar ice sheets in Antarctica, Greenland melting 3 times faster than in ’90s
Ice Sheet Loss at Both Poles Increasing, Study Finds
Projections of sea level rise are vast underestimates
“Hard” “Authoritative” Evidence Of Climate Change Begins To Overwhelm Even Fox

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A concise summary of climate change – science and politics

Here’s a relatively short (26 min) video of a lecture by Michael Mann. I think it gives a very concise and accurate picture of the current science of climate change and the political attacks on climate scientists (Mann calls this the scientization of politics).

via The Hockey Stick and the Climate Wars – Michael Mann Speaks at SOS 2012 on Vimeo.

From the video description:

Michael E. Mann- Director of the Earth System Science Center gives a very eye-opening presentation at the 2012 Sustainable Operations Summit. Mann’s presentation highlighted themes from his most recent book: The Hockey Stick and the Climate Wars: Dispatches from the Front Lines. In his talk, Mann discussed the “Hockey Stick,” a graph he created with his colleagues to depict changes in Earth’s temperature dating back to 1000 AD. The graph was featured in the Summary for Policy Makers portion of the 2001 report of the Intergovernmental Panel on Climate Change (IPCC) and became an icon in the debate over human-caused climate change. Mann told the story behind the Hockey Stick, using it as a vehicle for exploring broader issues regarding the role of skepticism in science and the relationship between science and politics.

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In the front lines of the “climate wars”

Here’s another book to look out for – The Hockey Stick and the Climate Wars: Dispatches from the Front Lines. It will be published at the beginning of March .

The author, Michael Mann,  has been a central figure in the “climate wars.” His research into paleoclimate has been a particular target for climate sceptics/contrarians/deniers. And despite their claims that his work was discredited it has in fact been supported and replicated by other climate scientists. It also received endorsement from the The National Research Council of the US National Academies. (See and download Surface Temperature Reconstructions for the Last 2,000 Years (2006) )

Publisher’s description of book

This is how the publisher describes the book:

“In its 2001 report on global climate, the Intergovernmental Panel on Climate Change of the United Nations prominently featured the “Hockey Stick,” a chart showing global temperature data over the past one thousand years. The Hockey Stick demonstrated that temperature had risen with the increase in industrialization and use of fossil fuels. The inescapable conclusion was that worldwide human activity since the industrial age had raised CO2 levels, trapping greenhouse gases in the atmosphere and warming the planet.

“The Hockey Stick became a central icon in the “climate wars,” and well-funded science deniers immediately attacked the chart and the scientists responsible for it. Yet the controversy has had little to do with the depicted temperature rise and much more with the perceived threat the graph posed to those who oppose governmental regulation and other restraints to protect our environment and planet. Michael E. Mann, lead author of the original paper in which the Hockey Stick first appeared, shares the real story of the science and politics behind this controversy. He introduces key figures in the oil and energy industries, and the media front groups who do their bidding in sometimes slick, bare-knuckled ways to cast doubt on the science. Mann concludes with an account of the “Climategate” scandal, the 2009 hacking of climate scientists’ emails. Throughout, Mann reveals the role of science deniers, abetted by an uninformed media, in once again diverting attention away from one of the central scientific and policy issues of our time.”

McCarthyist attacks on science

Henry Waxman, Democratic member of the U.S. House of Representatives, former chairman of the House Energy and Commerce Committee said this of Michael Mann:

“As one of the nation’s leading climate researchers, no one has felt the brunt of the attacks from politicians and the fossil fuel industry more than Michael Mann. This is his personal account from the center of the maelstrom, documenting the lies and distortions about his work and his heroic efforts to stand up for scientific truth.”

Mann has certainly been one of the most high profile victim of the current McCarthyist attacks on climate science and scientists. This still continues. But he is not the only target. This has become such a problem that A Legal Defense Fund for Climate Scientists has been set up. You can find out more about the fund at its new web site and its recent press release –  Climate Science Legal Defense Fund Gets New Backing. As the press release says:

“The fund is designed to help scientists like Professor Michael Mann cope with the legal fees that stack up in fighting attempts by climate-skeptic groups to gain access to private emails and other correspondence through lawsuits and Freedom of Information Act requests at their public universities.”

The fund will also:

“Educate researchers about their legal rights and responsibilities on issues surrounding their work;

Serve as a clearinghouse for information related to legal actions taken against scientists; and

Recruit and assist lawyers representing these scientists.”

Another important  book to look forward to.

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