Archive for March, 2007


Saturday, March 31st, 2007

Hello. This is my first blog for First, I want to thank the organizers and the AMS for asking me. Second, as introduction, what I will write about here follows from a class that I have been teaching the last two years at U of Michigan. This class throws all of the pieces out there, science, policy, business, ethics, public health, geo-engineering, energy, current law, beliefs, etc., and tries to look as these pieces as a system. We have projects where we try to develop solutions, or at least strategies to develop solutions. More thanks – I want to thank my excellent students, the guest lecturers in the course, and many seminar speakers who come through the university.

For my first entry I will write about the intersection between climate science and policy. If we look at the development of climate knowledge from scientific investigation, then there are two types of knowledge. The first type of knowledge is a quantitative representation of climate parameters and their correlated behavior. An example of this type of knowledge is a prediction of the temperature, and it is the prediction of rapidly warming temperature that motivates the possibility of climate policy. The other type of knowledge is an estimate of uncertainty. Good scientific method is always accompanied by an analysis of error sources and some measure of the uncertainty. Uncertainty can always be used to prevent the development of policy. Therefore, the idea of climate science as a constant march to reduce uncertainty in our statements of predicted climate change is not very well posed. There is always uncertainty, and in complex systems, we discover new sources of uncertainty. Hence, there is always a reservoir of uncertainty to keep policy from converging around the gravity of scientific evidence. (more…)

Uncertainty and Climate Risk Assessment

Thursday, March 22nd, 2007


Risk is often thought of as the product of consequences and likelihood—what can happen, and what are the odds of it happening. Both of these factors are important in determining whether and how we address specific risks. For example, even though the consequences of an asteroid colliding with the Earth would be catastrophic, the likelihood of it happening is extremely low in a time frame relevant to human society, and therefore, while we pay attention to the possibility, we generally focus on other concerns that may have fewer consequences, but have a much higher likelihood of occurring.

Projections of future climate change and climate impacts are inherently uncertain. To be clear, the question is not whether the climate will continue to warm, driven by greenhouse gas emissions from human activities. The overwhelming scientific consensus is that temperatures will continue to rise globally as a result of greenhouse gas emissions. Rather, the question is how much the climate will warm, how fast, and what the impacts will be. In very general terms, climate policy is about managing risk: assessing the potential impacts of climate change, judging how likely it is that various impacts will occur, and determining how our policy choices (discussed broadly here) will affect those risks. Uncertainty is a critical factor in assessing both climate risks and the effectiveness of different policy strategies. (more…)

Are clean fuels finally coming of age?

Tuesday, March 20th, 2007

Daniel Kammen
Class of 1935 Distinguished Professor of Energy
Energy and Resources Group, Goldman School of Public Policy
Co-Director, Berkeley Institute of the Environment
Editor-in-Chief, Environmental Research Letters
University of California
Berkeley, CA 94720-3050
URL: &
Date: March 20, 2007

The year 2007 may well go down in history as the year we finally began to seriously act collectively to address global warming. I say ‘collectively’ intentionally, and for a specific reason. We have already seen a number of nations – the entire European Union, all of Scandinavia, Japan, and a significant number of individual states in the United States – all commit to varying degrees to climate legislation and targets that could, if they become universal – finally put us on a path to address global warming. These efforts are each significant, and include such key goals as those in Sweden, that aims for an oil free economy by 2020, to the Global Warming Solutions Act in California that aims to reduce greenhouse gas emissions from the entire state economy by 25% over the next two decades. (more…)

Society’s Options—The Broad Overview

Friday, March 16th, 2007

Society has four general options for addressing human caused changes in climate. We could take no upfront preventative action. I’ll call this the wait-and-see approach. We could reduce our greenhouse gas emissions (mitigation). We could improve our ability to cope with climate impacts (build our adaptive capacity). For example, building codes could require structures to withstand more severe storms, or we could restrict development in flood prone areas. Finally, we could deploy global changes that attempt to counteract the effects of our greenhouse gas emissions (geoengineer). One prominent geoengineering idea is to inject reflective particles into the atmosphere to decrease slightly the amount of the sun’s energy that reaches the earth’s surface.

Each of the four options has proponents and critics, advantages and disadvantages. A full treatment will take many posts, but for today I’ll set the stage with a broad overview. (more…)

Equity, The Stern Review, and What We Should Do About Climate Change

Monday, March 12th, 2007

Climate change may or may not be the world’s most important challenge, but it is certainly the most complex. Indeed, it may be the most complex challenge the world has ever faced.

That is why the conclusions reached by the Stern Review stand out. Sir Nicholas Stern and his colleagues looked carefully at this complex problem and concluded, simply, that “the benefits of strong, early action considerably outweigh the costs.” Previously, the “mainstream” economics literature had concluded that emissions should be reduced now but that “strong” action should be delayed. (more…)

The Stern Review and the role of benefit-cost analysis in climate change policy

Friday, March 9th, 2007

Sir Nicholas Stern released in October 2006 the Stern Review: The Economics of Climate Change, the first major government-sponsored benefit-cost analysis of climate change. This report concludes that “the benefits of strong, early action on climate change outweigh the costs” – unmitigated climate change would impose damages equivalent to 5–20% of global per capita income, but stabilizing atmospheric greenhouse gas concentrations at 550 parts per million carbon equivalent would only cost the world about 1% of global GDP annually.

The Stern Review has received substantial attention in policy and academic circles. Stern testified before the U.S. Senate, and Resources for the Future and Yale University held symposia on the report. The Review of Environmental Economics and Policy will publish several papers reviewing the report. The Economist and the New York Times have reviewed the report. The Stern Review raises important questions about the evaluation and design of policy. Let me focus on just a few here – one on the benefits and one on the costs sides of the ledger, and two about policy design. (more…)

Welcome to!

Thursday, March 1st, 2007

Society faces complex choices in dealing with climate change. The policies we adopt have the greatest chance to benefit society if they are grounded in the best available knowledge. Unfortunately, gaps in understanding among scientists, policy makers, journalists and the public permeate nearly all aspects of the issue and constitute a major barrier to the adoption of well-informed responses to the threats posed by climate change.

ClimatePolicy will be a source of information and will work toward a more fully informed debate. We’ll discuss a wide range of topics that span scientific understanding, impact assessment, policy analysis, and the value judgments that shape people’s policy preferences. This will improve the policy process by explicitly identifying existing knowledge and exploring the limits to it. Our goal is to inform policy, rather than to advocate for specific policy solutions. (more…)