Monday, January 25, 2010

Problems with IPCC science

There have been a couple of issues raised regarding the science behind the IPCC reports raised recently, one a clear - and bad - error and the other a misreading of what the IPCC report actually said.

The error on glaciers was the statement in one section of the IPCC report that the Himalayan glaciers would be gone by 2035 at current rate of melting. This is not a claim supported by the evidence. While Himalayan glaciers are melting rapidly, these glaciers are huge. There is no known physical mechanism related to atmospheric temperature that could melt them all by 2035.

This was a bad error, and one that should have been caught earlier. However, it was caught - that it was the scientific process is all about, so it is not bad science that a mistake was made and then corrected.

It is bad politics, unfortunately. This is why politicians rarely admit an error even when they have made a blatant one. They understand that the public is not very forgiving of mistakes. And it is even less forgiving of mistakes by scientists. There is obviously a need for better checking of the material that goes into IPCC reports. Hopefully, the next one will not contain any errors approaching this magnitude. But in the meantime, we will have to deal with increasingly strident calls by those who disbelief AGW theory for the IPCC to be disbanded or some such. And the public may well listen now that an error has been admitted to. It makes our efforts more difficult, which is a sad thing. (Admitting the error is not a sad thing; it making things more difficult is sad.)

The other issue is the one to do with claims regarding increases in damage caused by extreme weather events as the world warms. There are accusations that the IPCC used one paper that made a claim that there was evidence that damage had increased over the past 30 years and that it was linked with global warming. However, while the IPCC did use this paper, it also looked at others that did not show an increase. The IPCC was balanced in its call for more examination of this issue. It put the view that there were risks associated with this, but that there was not enough evidence to quantify them.


  1. The thing missing from the news reports that I have read on "glaciergate" is how big a proportion / how much of a key element of the IPCC report in question it was. If it is a minor part of the report, then its importance has been drastically overstated.

  2. james,

    "This claim did not make it into the summary for policy makers, nor the overall synthesis report, and so cannot be described as a ‘central claim’ of the IPCC."

    This is from:

    It was in the section on future impacts. The way the IPCC reports are broken up seems to be an issue, as the main focus for scientists and scientific review is on the section 'the scientific basis'.

  3. This is the IPCC synthesis report statement on glaciers:

    "Climate change is expected to
    exacerbate current stresses on water resources from population growth and economic and land-use
    change, including urbanisation. On a regional scale, mountain snow pack, glaciers and small ice
    caps play a crucial role in freshwater availability. Widespread mass losses from glaciers and
    reductions in snow cover over recent decades are projected to accelerate throughout the 21st
    century, reducing water availability, hydropower potential, and changing seasonality of flows in
    regions supplied by meltwater from major mountain ranges (e.g. Hindu-Kush, Himalaya, Andes),
    where more than one-sixth of the world population currently lives."

    It is the main report, and did not include the 2035 claim.

  4. In other words, "maintstream journalism + science = sensationalism". Sigh.