In his letter to the FT of Septermber 25, 2009 Lord Nicholas Stern asserts that current goals for emissions reductions in the context of modest economic growth imply a need to cut emissions per unit of GDP by at least 75% across the US, EU, Japan, Indonesia, Brazil, and China. However, he is a bit too glib when he claims that the current pace of technological progress, efficiency gain potential and deforestation "make it clear" that such a goal can be achieved in the next 20 years. First, while deforestation may indeed play a role in taking up excess carbon dioxide, it is unrelated to the decarbonization of the global economy and should not be included as a strategy toward that end. Second, Stern's 75% improvement in carbon intensity across these countries implies a 6.9% annual rate of decarbonization, which is about 4 to 5 times faster than historically has occurred and higher even than the highest sustained rate of decarbonization ever achieved in a large economy. The technologies needed to accelerate decarbonization are not yet ready at scale, and there may be limits to how fast and how far efficiency gains can take us. Further, we are taking on this challenge from, at best, a "standing start" as rates of decarbonization have slowed in many countries in the current decade.
The pace at which policy makers are stepping back from grandiose expectations for the upcoming Copenhagen climate meeting should tell us that the scale of the challenge is at least implicitly understood by those who would be faced with meeting goals that no one currently knows how to meet. Consequently, overly optimistic and misleading claims of the achievability of the rate of decarbonization suggested by Lord Stern, and others, only delay the time until we can adopt an approach to climate policy grounded in realism rather than exhortation.
Roger Pielke Jr., Professor
University of Colorado
Christopher Green, Professor
04 October 2009
Unpublished Letter to the FT
Chris Green and I sent this in one week ago, in response to a letter from Lord Nicholas Stern. It was not published so we are sharing it here.