Setting the science straight on the IPCC’s Himalayan glacier error
The melting of Himalayan glaciers – and the IPP’s so-called “2035 error” – is a hot issue right now.
Towards the end of last year, I attended a press conference on the melting of the Himalayan glaciers at the American Geophysical Meeting. It was a press conference like any other – a non-descript, high-ceilinged room, a panel of scientists, some slides with charts and bullet-points, along with an assembled crew of journalists. The scientists spoke about the effects of black carbon, or soot, on the glaciers, and I thought it was some pretty compelling stuff.
A few weeks later, the melting Himalayan glaciers hit the news in a big way – but no one was talking about soot. It was revealed in a letter to the journal Science that the IPCC was gravely mistaken on its statement that “the likelihood of [the Himalayan glaciers] disappearing by the year 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate.” A team of glaciologists had traced that estimate back to an unconfirmed story in New Scientist, and flatly called it “wrong.” The glaciers are still melting, but not at that extremely rapid rate.
The rest is (recent) history, and the mistake has provided a foundation to shake public confidence in the 2007 IPCC report, which is intended to serve as a kind of Bible for climate science.
Recently, I called up Jeffrey Kargel, a hydrologist at the University of Arizona, who was on the AGU panel. He had written a fairly comprehensive backgrounder for the press conference, asserting that the media event would “reproduce and reinforce” some of the errors causing confusion about the state of Himalayan glaciers. Kargel was also an author on the letter to Science, which broke the story to mainstream media.
As Kargel tells it, he did not ask for this particular role. “I had nothing to do with the IPCC,” he told me. “Someone screwed up and you don’t know what to do about it.”
Kargel said he noticed the 2035 error glaring from the page the first time he read the document. Many of his colleagues noticed it as well, he said, but unfortunately not soon enough to stop it from going to print. “It was a comedy of errors in one paragraph, in a document that otherwise did well to address the state of Himalayan glaciers,” he said. Kargel described the reaction of glaciologists to the 2035 disappearance date as a collective eye-roll.
The Himalayan glaciers are melting, Kargel said, but they are doing so at different rates, and responding differently to climate change in different regions. It’s deeply complex, and there is much that scientists still don’t understand. However, they did know that 2035 was patently wrong, and made no significant effort to correct the mistake until now.
I asked Kargel why this wasn’t reported, as he described that it was impossible to talk to any journalist post-IPCC without them asking about 2035. “We would say, ‘That’s not right’ and not elaborate,” he said. “This was the case until I came eyeball-to-eyeball with 2035. It’s not that I wanted to avoid talking about it, it was just so wrong it wasn’t worth discussing.”
The eyeball-to-eyeball event he’s referring to was a paper by an Indian scientist named V.K. Raina, that was reported on in the journal Science. A Science reporter called Kargel to comment on the study. Kargel read it, and found an error which he thought was on the same scale as the IPCC’s 2035 error. In the last three paragraphs of the study, Kargel said, without any scientific support, Raina claimed that the glaciers are responding on a 50,000 – 60,000 year basis.
“It was a strange balancing act,” said Kargel. “Raina cast doubt on 2035, which I knew was wrong. But Raina committed a big error in saying glaciers don’t respond to a human time scale.”
This put Kargel in a position where he felt he had to correct Raina’s study. Meanwhile, Kargel’s colleague, Graham Cogley, had tracked down the unreliable source of the 2035 error. “We are honor bound not to hide error under a bushel basket,” Kargel told me. “We had no choice but to go forward” with the public correction on both Raina’s study and the IPCC.
Kargel and Cogley assembled a team of glaciologists to set the record straight on the science. Four wrote the letter to Science (which the journal waited a few months to publish) and 17 put together the backgrounder for the AGU press conference.
Kargel expressed feelings of anger and frustration about the reaction to the 2035 correction. He said he had read blogs and comments about it. “I know people who put decent, hard work, their souls and minds into [the IPCC report]. It’s heartbreaking to see so many people getting into conspiracy thinking,” he said. “All we wanted was to get the IPCC to take corrective action.”
Indeed, climate skeptics have taken the 2035 mistake, coming on the heels of the hacked “Climategate” emails, to indicate that the entire IPCC, and by relation, the entirety of climate science, is faulty. But Kargel, and many other scientists say it proves nothing, other than a flawed review process on that paragraph – and possibly other sections of the document. “How could you have so many thousands of pages and not have errors?” Kargel asked rhetorically. He went on, “Scientists have to be more proactive. How can it be that one error can castigate an entire organization?”
Science is an evolving process. Knowledge is constantly being sought, and errors are always being found. Kargel and his colleagues continue to try and understand how the Himalayan glaciers are reacting to climate change – and how that will impact the billion people who rely upon them. Kargel told me he is confident that the next IPCC assessment will be a much stronger document, drawing on the lessons learned from the IPCC’s mistakes about the Himalayan glaciers.