The Copenhagen diagnosis: sobering update on the science

Ahead of talks in Copenhagen, a group of leading climate scientists has issued a new report summarising the most recent research findings from around the world and concluding that scientists have underestimated the pace and extent of global warming. The report - titled The Copenhagen Diagnosis - finds that in several key areas observed changes are outstripping the most recent projections by the UN’s Intergovernmental Panel on Climate Change and warns that “there is a very high probability of the warming exceeding 2C unless global emissions peak and start to decline rapidly” within the next decade.

The report points to dramatic declines in Arctic sea ice, recent measurements that show a large net loss of ice from both Greenland and Antarctica, and the relatively rapid rise in global sea levels - 3.4 millimetres per year - as particular reasons for concern. Sea-level rise this century, it states, “is likely to be at least twice as large” as predicted by the most recent IPCC report, issued in 2007, with an upper limit of roughly two metres.

“Sea level is rising much faster and Arctic sea ice cover shrinking more rapidly than we previously expected,” Stefan Rahmstorf, department head at Germany’s Potsdam Institute for Climate Impact Research, said in a press release accompanying the report. “Unfortunately, the data now show us that we have underestimated the climate crisis in the past.”

According to the report, which was released today, there are several elements of the climate system that could reach a “tipping point” in coming decades if current emissions trends continue. The report notes that even at current greenhouse gas concentrations, it is already “very likely” that a “summer ice-free Arctic is inevitable”. The Greenland Ice sheet, too, the report warns, “may be nearing a tipping point where it is committed to shrink”.

The report’s 26 authors include scientists from Germany, France, Switzerland, Austria, Canada, the US, and Australia. Most were also authors of the last IPCC report, and donated their time to draft The Copenhagen Diagnosis. The University of New South Wales’ Climate Change Research Centre provided logistical support.

“We thought that the IPCC report from 2007 was a superb report, but of course science doesn’t stand still,” Richard Somerville, a climate modeler and professor emeritus as the Scripps Institution of Oceanography, said. “And we thought it would be helpful if we could provide some kind of updated assessment.”

In an email message from Antarctica, where he is doing fieldwork, Robert Bindschadler, of NASA, said the group had been prompted to write the report by “the rapidity and serious consequences of climate change”.

Georg Kaser, a glaciologist at the University of Innsbruck, said he hoped policymakers would respond to the report by deciding to “totally phase out fossil-fuel burning within the next two decades”.

“Dreaming is allowed,” he added. “Frankly speaking, I would not like to be a policymaker that has just two options: one, phasing out fossil fuel burning immediately, or two, committing our society to major and long-lasting changes in the climate system.”

The report was already completed but not released by the time world leaders, including President Obama, announced in Singapore on November 15 that they had abandoned the goal of reaching a legally binding agreement in Copenhagen. Since then, several countries have announced commitments to reduce their greenhouse gas emissions, including South Korea, which last week pledged to a cut of 20 per cent below “business as usual” by 2020, and Brazil, which promised reductions of 40 per cent below current projections by 2030. But the United States, with some of the highest per capita emissions in the world and the second-highest overall emissions, after China, has made no commitment, and legislation to curb emissions, which narrowly passed the House this year, is not expected to be taken up by the US Senate until after the Copenhagen session is over.

Andrew Weaver, a climate modeler at Canada’s University of Victoria and one of the authors of The Copenhagen Diagnosis, said he found the announcement that world leaders were abandoning the goal of reaching a binding agreement this year “unacceptable”.

He went on: “Maybe they should be honest, and stand up and say, ‘You know what? As your political leaders we do not accept that we owe anything to future generations.’ I don’t think they’d ever say that, but this is what they are saying if they don’t deal with this problem.”