PA52A-01 10:20h
Formulating Climate Policy in Terms of Risk Management
Much discussion of long-term climate targets and short-term Kyoto-type agreements is misdirected because of a lack of widespread understanding of uncertainty in human-climate interaction and of the crucial roles of inertia in social systems, the stock-pollutant nature of greenhouse gases, and the influence of long lags in the ocean. A clearer perception of the risk-management nature of the issue requires a joint analysis of forces driving greenhouse emissions and climate system response, taking these factors into account. It is a task requiring the integration of methods and models of the natural (climate) sciences and the social sciences. This talk will discuss the challenge and present an example of the needed studies, highlighting controversies and problems attending this type of integrated analysis.
PA52A-02 10:40h
Probabilistic Integrated Assessment of "Dangerous" Climate Change
Uncertainties in projections of future climate change due to natural and social parameters of the climate system are often used as a basis for decisions to delay climate policy. However, if we wish to influence the trajectory of future climate change and avoid potentially "dangerous" climate impacts, we must make decisions under uncertainty, an accepted practice in many other sectors. This talk will present a probabilistic conceptual framework for defining "dangerous" climate change, a policy-relevant impact threshold which the US and over 190 other signatories to the UNFCCC have committed to preventing. It will also present an example of application of this metric to projections of future climate change, to demonstrate the linkage of climate policy decisions to risk management of "dangerous" climate change.
PA52A-03 11:00h
Probabilistic analysis of climate stabilization targets and the implications for precautionary policy
A cruicial influence on precautionary policy is the uncertainty of the climate sensitivity - the equilibrium response of the global mean surface temperature to a doubling of CO2 . The climate sensitivity has been represented in the published literature by a wide variety of descriptions, including both formal probability density functions (PDFs) and simple ranges. How to utilize these PDFs and quasi-PDFs is a crucial question at the science-policy interface. Conventional risk analysis methods can be applied, including monte carlo methods with a probabilistic treatment of the climate sensitivity. However, there is no obviously correct way perform such analyses; slightly different framings of the policy question (e.g., targets for CO2 or all GHGs) lead to different modeling schemas. In this paper, I present three simple models that use a range of climate sensitivity PDFs to generate PDFs for the "implied equilibrium temperature" (the hypothetical equilibrium temperature if radiative forcing were to stabilize at a given level) for different GHG stabilization policies. The first takes a fixed value of radiative forcing or CO2-equivalent concentration; the second takes a fixed CO2 concentration and a stochastically defined value for net non-CO2 forcing; and the third takes a fixed increase in radiative forcing and a stochastic value for current net forcing. In addition to temperature PDFs for different policies, I calculate the policy targets implied by given temperature/probability thresholds. These indicators provide the necessary framework for a meaningful debate on precautionary policy, in which such a temperature/probability threshold is a logical policy goal. Finally I show the policy implications of various precautionary targets, particularly those using the widely proposed target of no more than 2§C increase above pre-industrial temperatures. I demonstrate that a high probability of staying below 2§ requires stabilization levels on the order of 400 ppm CO2-equivalent, far below the stabilization levels currently considered realistic.
PA52A-04 11:20h
Radiative Forcing of Climate: Expanding the Concept
Knowledge of the natural and anthropogenic processes that affect the Earth's energy balance is critical for understanding how climate has changed in the past and will change in the future. Effective metrics are needed to quantify and compare the various forcings that affect climate. For the past few decades, global mean radiative forcing at the top of the atmosphere has been reported extensively in climate change assessments, and it provides the foundation for policies directed at climate change. However, recent research on non-conventional climate forcing agents has raised doubts about the value and applicability of the radiative forcing concept. At the request of the U.S. Climate Change Science Program, the National Academies convened a committee to examine the current state of knowledge on radiative and non-radiative forcings of climate including contributions from greenhouse gases, aerosols, land-use changes, volcanoes, and solar variability. The committee was asked to identify key gaps in understanding, and to chart near- and longer-term research priorities for improving understanding and projections of climate forcings. The committee considered the radiative forcing concept itself, its continuing relevance in research and policy settings, and options for expanding the concept to account for non-conventional forcings such as aerosols and land-use changes. The findings and recommendations of this study will be presented.
PA52A-05 11:40h
Where the Rubber Hits the Road: The Politics and Science of Climate Change in Congress
Scientific understanding of the magnitude and rate of global and regional climate change is being actively communicated to Capitol Hill, however this information is being framed within the political debate that has brought climate change policy in the U.S. to a practical standstill. Efforts by scientists to communicate to Congress advances in the understanding of climate change have been obscured by policy-makers, lobbyists and some scientists themselves, into two polarized camps: those that who claim that current climate change is insignificant and/or of non-anthropogenic origin, and those who predict irreversible climate change in the near future and advocate a precautionary approach to anthropogenic contributions. As a science policy advisor to a Member of Congress active in the climate policy debate over the past year, I have observed firsthand most of the scientific information on climate change presented to Congress being partitioned into these camps. The political debate surrounding climate change policy has centered on the policymakers' understanding of scientific uncertainty. Communication by researchers of the definition of risk and uncertainty in climate science, in the language and framework of the legislative debate, is of utmost importance in order for policymakers to effectively understand and utilize science in the decision-making process. A comparison with the recent white paper on climate change policy developed by the UK Science and Technology council and currently adopted by UK policymakers demonstrates the importance of a general public understanding of the existing magnitude of climate change, uncertainties in the rate of future climate variability and its associated economic and social costs. Communication of research results on climate change has been most effective in the policy debate when framed within the context of economic or security risks in the short term. Other effective methods include communicating local and regional climate scenarios and associated probabilities to individual policy-makers, as is currently being utilized to promote sponsorship of the Climate Stewardship Act in Congress.
PA52A-06 12:00h
Political/Institutional Barriers To Effective Climate Policy
So far, much integrated analysis of climate policy has largely focused on the interaction of physical and economic systems. Political and institutional factors can also profoundly affect policy outcomes. Recent analyses have suggested that the lack of institutional structures may make international emission limitations unenforceable and international emissions trading unmanageable. This presentation will describe the reasons for regarding these analyses as serious challenges to the feasibility of the most widely discussed strategies for managing climate change.