Yale 360


Climate Scientists Respond to IPCC Critics

Snowstorm at Donner Pass, January 2010 (Photo: Gretchen Weber)

Snowstorm at Donner Pass, January 2010 (Photo: Gretchen Weber)

As we all know, climate scientists have been on the hot seat lately. Among other recent incidents, they’ve drawn fire for the leaked East Anglia emails and for the now-retracted assertion in a 2007 report from the Intergovernmental Panel on Climate Change that Himalayan glaciers might be gone by 2035.  In both cases, researchers admitted missteps and expressed regret. But they say neither incident invalidates the mass of evidence that the Earth is warming and that human activity is a likely cause.

On a call with journalists this week, three leading scientists defended the IPCC, its processes, and climate science in general.  Fielding questions were Penn State glaciologist Richard Alley, Scripps Institute climate scientist Richard Somerville, and Chris Field, director of the Carnegie Institute Department of Global Ecology at Stanford.

“There are errors, and you can find errors on both sides,” said Alley, referring to the fact that previous IPCC reports had underestimated sea-level rise.  “It’s done by humans. It’s not perfect.  But these errors in no way impact our fundamental understanding that we’re adding CO2 to the air, that this is turning up the Earth’s thermostat,” he said.

Somerville made a similar point about the false Himalayan prediction in the 2007 report.

“I liken what’s happened here to the occasional error that happens a bank statement or a phone book,” he said, noting that the 2007 report was 3,000 pages long.

Just because a bank makes a mistake on your statement, he argued, “That’s not a reason to distrust banks.”

The scientists defended the IPCC standards and review process, but supported the IPCC’s recent announcement that it will seek an outside review for future studies in efforts to avoid mistakes in the future.  It’s not clear yet what the independent review process will look like.

“The best thing we can do to push errors to the minimum is to have more eyes looking and to have more expertise and more transparency,” said Field.

There’s no question that errors such as the one about the Himalayan glaciers have provided fodder for critics of climate science and may have contributed to a recent decline in public concern about (and belief in) global warming. During their call this week, the climate researchers bemoaned the fact the urgency of their findings isn’t getting through.

“The fact is that we don’t have forever to decide to reduce emissions of greenhouse gases,” Somerville said. “That’s not something you can procrastinate for ever. Mother Nature imposes a time scale and it’s measured in a few years, not a century.”

Scientists are being forced to defend their work against attacks that are based on policy, not science, Somerville said. The IPCC has a mandate to be policy-neutral, and its goal is to provide information that is policy-relevant but not policy-prescriptive, he said.

“And yet, when you take apart the criticisms that have been made of IPCC and climate science in general, you’ll find, I believe, that in many cases they are motivated by policy concerns rather than scientific concerns,” he said.  “And so I think you’ll find individuals and organizations who have strong views on carbon taxes or government participation in free markets or ceding sovereignty of one country by signing international agreements – all kinds of things like that that are disguised as concerns about the science.”

There’s an interesting conversation happening at Yale Environment 360 about the future of the IPCC.  Robert T. Watson, chair of the IPCC from 1997 to 2002, argues in an essay that while there’s room for improvement in terms of implementation, the IPCC’s procedures are sound.   On the other side, University of Colorado Environmental Studies Professor Roger A. Pielke argues for sweeping reform, citing, among other criteria, a need for a mechanism for resolving allegations of error and a policy pertaining to real and perceived conflicts of interest.