Glaciergate in perspective

The “Glaciergate” story is about a claim in the 2007 IPCC report that the Himalayan glaciers would melt by 2035. It turns out that the evidence for this claim was from a speculative comment made by a not-very-prominent glaciologist in New Scientist in 1999. The Times and The Express have gone to town with this story claiming that it undermines the whole of the IPCC.

So, what does it really mean?

A little bit of background…

To understand the significance of Glaciergate, we first need to understand how the IPCC works. This is my perspective.

The Intergovernmental Panel on Climate Change (IPCC) is split into 3 Working Groups:

  • WGI: The Physical Science Basis
  • WGII: Impacts, Adaptation and Vulnerability
  • WGIII: Mitigation of Climate Change

Each group produced a separate report in 2007. Each report was about 1000 pages long. All this information was also summarised in a Synthesis Report. This was the fourth IPCC report round, the others were in 1990, 1995 and 2001.

WGI reviews and synthesises all the work on the physics and chemistry of the Earth system and tries to make projections of how things like temperature, rainfall and atmospheric circulation will change in the future. I refer to this report a lot in my work as a meteorologist/climatologist.

I know a little about Working Group II – as well as climatologists, it is written by hydrologists, glaciologists, economists, social scientists and medical scientists and considers the potential impacts of climate change.

I have very little idea about what goes on in WGIII. I also confess that I’ve never looked at the WGIII report. WGs II and III rely on a certain degree of informed speculation; it is their business to ask what the world would be like, and what we could do about it, if certain things happen based on the projections from WGI.

Was the Himalayan meltdown a “central claim” (as reported by The Times) in the IPCC report?

The 2035 date relating to the Himalayas appeared in one sentence in Chapter 10 of the Working Group II report. So this is one sentence in nearly 3000 pages. As far as I can see (please correct me if I’m wrong) the 2035 claim was not repeated in the WGII Summary for Policymakers or the overall Synthesis Report. Furthermore, as investigated by the Deltoid Blog, this prediction about the Himalayas was almost universally ignored by the press in 2007 when the report was published. The 2035 prediction was clearly not a central claim.

How did the “2035” date get into the report?

As we said above, WGII is relatively speculative by nature. In this context, was Glaciergate a reviewing error rather than an attempt to distort the science? Well, one of the reviewers for this section (Dr. Hayley Fowler from the University of Newcastle, see here for the reviewer comments for WGII Chapter 10) actually picked up the unjustified “2035” claim and suggested some proper peer reviewed papers to improve the relevant section. The report author’s response to Dr. Fowler’s comment was: “unable to get hold of the suggested references”. This response is clearly not adequate but it is more than conceivable that one of many suggested revisions was missed rather than ignored deliberately to overstate the impact of a changing climate.

Indeed, this is the first questioning of anything in the IPCC report that I can remember since it was published in 2007 – that says a lot for the usual skill and thoroughness of the report reviewers, despite the failure in this one case, and suggests that there wasn’t a systematic effort to exaggerate climate impacts.

Most importantly, though, the WGII glacier claim changes absolutely nothing about the fundamental science behind climate change that appears in WGI. To dismiss the IPCC because of Glaciergate is like saying you wont trust anything in The Times newspaper because they once printed a football result wrong. The WGI science is all robust and, if anything, quite conservative in its claims and projections.

“Dr Rajendra Pachauri (IPCC Chair) is a former railway engineer with a PhD in economics and no formal climate science qualifications”

The Express article also makes the above statement as if it also undermines the whole of the IPCC. If anything, it just shows that the reporter has very little idea what the IPCC actually does. Pachauri has worked in several different scientific disciplines and has headed a large organisation before. In my mind, that more than qualifies him to head the IPCC.

Anyway, if you’re looking for people with in depth knowledge of specific fields, then there are the WG Chairs. For example, WGI was chaired by Susan Solomon, who stands a pretty good chance of being awarded a Nobel prize for her work in the 1980s on the ozone “hole”. Beneath the WG Chairs, each chapter has at least 1 co-ordinating author and 1 lead author. Beneath them, each chapter also has many contributing authors, all experts in their field.  Their work is all reviewed by other experts.

This attack on Pachauri doesn’t hold up.

“The revelation is the latest crack to appear in the scientific consensus over climate change”

This claim was made in the Times article, with the other cited cracks being the CRU email theft and something about sea level rise estimates. This claim seems to assume that “consensus” means that no new work is going on in the climate sciences or at least demonstrates a complete ignorance of how science works.

Things will change in the science, which is exactly why the plans for the next IPCC report (due in 2014) are already well under way. These are exciting (and, if I’m honest, a little depressing) times for climate science so its disappointing that many people outside the research community don’t want to know about it!

Andrew Russell, a climate & weather researcher at the University of Manchester. This post was been reproduced (and slightly updated) from a post that originally appeared on Andy Russell’s Blog on 18÷1÷2010.