Paul Baer on The Stern Review

Paul Baer of EcoEquity has just written an article on the stern review and it's treatment of the
2 degree Centigrade stabilisation target. When I listened to Nicholas Stern talk abut his report at LSE he made it clear that he did not suggest either a 450ppm or 550ppm target but that stabilisation within that range would make economic sense.

This is where several people started to pull out hair, take in breath and pray for some sanity. Aubrey Meyer in particular was keen to point out the enormous difference between the two targets. I found myself with quite a few questions, foremost of which was, I doubt we can cope with 550ppm but what in the hell chance does Africa stand? And how is the economics of a generally poor continent like Africa accounted for in Stern's economic models? This preamble was just a clarification that Stern -- for reasons of 'realism'-- decided not to make recommendations other than a stupendously broad statement in favour of mitigation. Baer makes the point that the 2 degree target is implicitly abandoned as this is where stern did his modelling work and correspondingly, this is where the media get there figures from.

Here i state my ignorance of the reports details, i have read the full summary and listened to a two hour presentation but haven't read the somewhat more arduous 600 page report.

I think, however, that many of the points which Paul makes are well founded and as always enjoy the clarity of his reasoning. An excerpt is bellow and full article can be found here.

There is a great deal to be said about the importance of the Stern Review as a benchmark not just in the debate about climate policy, but also as a contributor to a broader debate about sustainability, economic growth, and global justice, and as an example of the role that economic argument plays in the science/policy domain. I hope in the coming months to take up many of these considerations, here and in other fora. But for now, I want to focus quite specifically on the key climate policy recommendations, and particularly on the implicit claim that the 2ºC target should be disregarded. And I will do so by highlighting the ways in which the Review actually incorporates catastrophic risks and their “valuation” - the “worth of an ice sheet,” as I suggest in the title. What I hope to show is that those of us who (prior to the Stern Review) thought that such risks justified the 2ºC threshold, have good reasons to reject Stern's conclusion.

Again, Stern does not explicitly dismiss the 2ºC threshold; but he endorses 450 ppm CO2-e as the lower limit on reasonable stabilization targets, in spite of it having at best even odds of staying below 2ºC and a roughly 20% chance of exceeding 3ºC. Thus, put simply, either:

1) Stern is wrong that stabilization targets lower than 450 ppm CO2-equivalent are not economically justified;

2) Stern is wrong that cost-benefit analysis should determine whether we try to stay below the 2ºC threshold; or

3) Stern is right, and we should quit arguing for lower stabilization targets that in fact have a high likelihood of staying below the 2ºC threshold.

As should be clear from my subtitle, the Stern Review in no way persuades me to abandon the goal of keeping below a 2ºC warming. Nor, I suspect, will most of those who also favor such an objective be persuaded by Stern to give up their “preference” for a more stringent policy. On the contrary, I suggest that in fact that Stern himself supplies many of the crucial premises in support of more stringent targets, and that it is only by making a series of necessarily controversial assumptions that he is able to conclude that accepting a 20% to 50% risk of exceeding 3ºC is economically warranted - and, implicitly, politically warranted.

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