My problems with the IPCC report

Below I will sketch two aspects of the IPCC's work which I find troubling. One relates to some interesting discussions on the thread The coming crisis of climate science which are worth pursuing in light of the two recent IPCC documents (Press release and Headlines document) reprinted here on Klimazwiebel. The other relates to the way the issue is presented by the IPCC.

Both the IPCC press release and the Headlines frame the climate issue exclusively as one of CO2 emissions. In so doing, other forcings are neglected and the message for policy makers is to perform a frontal attack on CO2 emissions (to create the ‘political will’ for such an enterprise, so to speak). This message has now been issued several times, with an inbuilt drama (the prospects get gloomier from assessment report to assessment report) but there is no effective policy outcome. There is no global agreement on the cards, and no national policies which radically cut CO2 emissions. CO2 emissions are rising and rising.

Assuming that the full text of all working groups in the new report will dedicate attention to non-CO2 drivers and other policy options, this will not get the same attention as the WG1 Summary for policy makers. This framing (or this construction) of the problem by the press release and 'headlines' will prime the political leaders and the mass media in a specific way. Is most unhelpful for practical political purposes.

While it is wise to (1) address the long term challenge of rising CO2, societies need to find ways to (2) cope with climate change (because we are committed to some change even if we stopped emitting today), and to (3) address non-CO2 climate forcings. The first strategy means technological innovation, the second adaptation, and the third exploiting co-benefits and applying pragmatic solutions for which regulations exist (mainly to do with air quality and protecting the natural environment). More about this can be found in the Hartwell Papers (here and here).

Now, on to the second problem. This is about presentation, or spin. As nature, and climate, do not speak to us 'through the IPCC', but are constructed by the IPCC in specific ways which select and emphasize specific aspects and neglect or attenuate others, we should pay careful attention to what is said, what is not said, and how it is said.

As Roger Pielke Jr. remarked, it is a good sign that the IPCC has abandoned the claim that tropical storms are getting more frequent and more violent (there is no such evidence, and Roger says 'Kudos to the IPCC for getting this right'). However, what is missing from the IPCC communications is an honest assessment of its previous statement, which it obviously thinks no longer tenable.

Generally, it would have been a good idea to compare the major messages from the 2007 report with those of the 2013 report and say where changes in assessment were made and why. The IPCC shuns such an exercise, and at its peril. The reason why it doesn't want to do this arguably (here I am offering a speculation) has to do with the desire to be perceived as sober, consistent, even infallible. Giving hints at a lack of confidence, the IPCC seems to assume, could provoke critical questions from the audience (and the heavy use of the word ‘confidence’ in the Summary for Policy Makers indicates that the IPCC wants to hammer home this exact point, that it has confidence…). But such a move gives rise to suspicion in the first place, as most of the interested audience can check for themselves what was said and how it was said last time, and if there are discrepancies between the two. So in reality this strategy is bound to backfire.

A very early example is the issue of climate sensitivity (which is now back at the centre of some commentators’ attention). As van der Sluijs et al have argued back in 1998, 'the consensus-estimate of 1.5°C to 4.5°C for climate sensitivity has remained unchanged for two decades. Nevertheless, during these years climate scientific knowledge and analysis have changed dramatically.'

One explanation offered by the authors is the following: ‘Advisory scientists also may have felt a need to create and maintain a robust scientific basis for policy action, which in our case means a consistent range of climate sensitivities. In may studies of science for policy, this has been seen as the prerequisite for maintaining support and credibility from all the actors and social worlds involved.’

In this case we have in fact seen a deviation from this range (upwards), only to now let it settle again in ‘safe terrain’. But the desire to present scientific statements in an authoritative manner while they are based on second guessing the audience of policy makers and the impact such statements make, is not helping the cause.