cc: jaeger@pik-potsdam.de, ccarraro@unive.it, m.hulme@uea.ac.uk date: Wed, 07 Feb 2001 18:22:27 +0100 from: Klaus Hasselmann to: tol@dkrz.de Thanks for the re-send, Richard. I find your list of three main topics for the instruments projects basically fine, but have a few points. As I'm not sure how to fit them into your writing, I'll just comment, without making a constructive proposal for change. 1) Voluntary agreements should be considered within the context of other government-controlled instruments such as emission permits. Alone, they will not get one much beyond no-regrets actions, even allowing for PR motivation and genuine concern for the environment. The forces of the market simply cannot be ignored by industry. However, one should investigate mechanisms for involving the stakeholders more strongly in the policy process (ECF is one such mechanism). 2) At the heart of the technological change problem is the long-term transition to essentially carbon-free energy technologies. I disagree that this "does not require new technologies", unless you ignore all questions of costs. Existing technologies at reasonable cost can perhaps reduce the carbon intensity by a factor of two. But the IPCC SRES 2A BAU scenario projects a factor 5 or so increase in emissions over the next 100 years, if I recall correctly, so that this would only bring us down to an increase of about a factor 2.5 . This still produces a global warming over over 6 degrees in the next centuries. We need to cut emissions down to about 1/4 of the present level in the next 100 years (or 1/20 of the BAU projection) to avoid a global warming of more than 2 or 3 degrees. This requires a radical change, which we cannot achieve by simply saving energy, being generally more efficient and installing windmills, using more hyropower, burning biomass, sequestering CO2, etc. The only solution in sight, if we ignore the nuclear option, is large scale solar power in sunny regions combined with hydrogen technology. I suggest we should focus on the problem of how to stimulate investment and learning-by-doing in this area. It is a problem which appears to have been largely side-tracked in the climate negotiations, which have become hung up on short-term second-order problems. And it will require some form of government incentive, as the existing technology today is simply too expensive to be competitive. 3) I agree that more work should be done on non-CO2 ggs like methane, but I would not rank this with high priority. CO2 is likely to dominate still more strongly over methane and other ggs in the future, and once we begin to tackle the methane problem (for example, by introducing other rice growing methods), the problem is not saddled with the long life times of CO2 (15 years for methane v. 100-200 years for CO2). I suggest we leave out this topic so as not to dilute the project too much. Cheers Klaus