## 25 September 2009

### Nicholas Stern's "New" Climate Policy

UPDATE: Nicholas Stern's spokesman, Bob Ward, shows up in the comments. Have a look.

Nicholas Stern, of the UK Stern Review Report fame/infamy, has published a paper outlining a "new" approach to climate policy (here in PDF). I put "new" in quotes because Lord Stern has adopted many on the most important recommendations that my colleagues and I have been making for several years now. But make no mistake, the approach outlined by Stern is his new paper is a radical departure from that which he espoused following publication of the Stern Review and much more (though not entirely) consistent with the recommendations that I and my colleagues have been making for several years now.

For instance, Stern accepts the need to look at the challenge of stabilization not as an emissions reduction challenge, requiring the use of a counterfactual baseline, but in terms of absolutes:
Thus we propose an approach of using absolute numbers rather than framing targets as a percentage reduction on a particular base year. Absolute numbers are preferable to percentages for two reasons: they allow us to keep a check on the basic arithmetic of the targets (so that they ‘add up’) and they avoid having to argue a theoretical reference baseline for percentages.
This of course was one of the core recommendations of Pielke, Wigley and Green (2008).

Next, Stern has discovered the simple arithmetic of emissions reductions via the Kaya Identity, both of which have been central to our work over the past few years:
If these emission targets are to be met without affecting the ambitions for growth in developing countries, it is evident that the emission intensity of output will need to change drastically over the next decades. This is a clear and fundamental conclusion from what we might call the ‘brutal arithmetic’. If we want to achieve both the strong emissions targets and the desires for growth then simple arithmetical logic requires a large fall in emissions per unit of output. In other words we must break the link between emissions and output. . . unless the USA, EU/Japan, Indonesia/Brazil and China reduce emissions per unit of output by a factor of 4 over the next 20 years, it will not be possible to grow at the desired rates and to reach the emission goals that sensible risk management requires. . . It is important to notice that the targets I have just described, and the implications they have in terms of reductions in emission intensity, have nothing to do with equity: they are just simple arithmetic based on what the science tells us on risk.
All of these concepts and ideas can be found in Prins et al. (2009), among other places. Prins is on the LSE faculty with Stern, so it would be no surprise to see fertile ideas taking root.

Whether Stern was actually inspired by these earlier works is less important that the fact that it seems that a more realistic approach to climate policy is taking hold in the mind of one of the issues most influential public intellectuals. And that is the best news on climate policy I've seen in a while.