Past Seminars by Series
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All Past Seminars | Climate Economics | Climate Science | Environmental EconomicsClimate Science
Climate Science Seminar: When Uncertainty is a Sure Thing: Risk Assessment for Climate Change
Date TBD
Phil DeCola (US Office of Science and Technology Policy)
Abstract:
Scientific Uncertainty and the Risks of Climate Change
May 7, 2009 (10:00 - 11:30 a.m.)
Jay Gulledge (Pew Center on Global Climate Change)
Abstract: There are basic mechansisms and consequences of human-induced climate
change that are known with high confidence. Other aspects are either
fundamentally uncertain, such as the climate sensitivity, or will remain
uncertain for many years, such as the timing and magnitude of change in
a particular location. Policy decisions must therefore be taken under
uncertainty and these decisions must take into account the risks of
climate change, which include potential surprises with severe
consequences for society. For more information, see a related book chapter that is available at:
http://www.pewclimate.org/docUploads/Gulledge-Risks-Uncertainty-Aspen08.pdf
Center for Clean Air Policy (CCAP) Urban Leaders Adaptation Initiative
March 25, 2009 (2:00 to 3:30pm)
Josh Foster (CCAP)
Abstract: The CCAP Urban Leaders Adaptation Initiative is building resiliency to climate change impacts through community action. Climate change causes disruptions to human, natural and built systems. It disproportionately impacts poor and vulnerable populations that have limited resources to adapt. built systems, including water infrastructure, buildings and transportation systems, are vulnerable to more frequent extreme weather events. Local governments are the "first responders" to social, environmental and economic disruptions resulting from natural disasters and must anticipate, prepare for and adapt to the impacts of climate change while minimizing greenhouse gas (GHG) emissions. In partnership with government leaders from several large counties and cities, CCAP launched the Urban Leaders Adaptation Initiative to: (1) Serve as a resource for local governments as they face important infrastructure and land-use decisions that affect local adaptation efforts; and (2) Empower local communities to develop and implement climate resilient strategies. The program goals and objectives for the next two to three years are to: (1) Operationalize key steps of the adaptation process with the end goal of implementing one or more specific policies and/or programs that incorporate resiliency strategies; (2) Formulate recommendations that help advance the development of national adaptation policy and/or programs that support local resiliency efforts; and (3) Disseminate findings on partners' actions and successes to inform and motivate other local communities in the U.S. and worldwide.
Josh Foster manages the Center for Clean Air Policy's (CCAP) Urban Leaders Adaptation Initiative, designed to equip U.S. partner cities and counties to make effective policy and investment decisions to increase their resiliency to the impacts of climate change. He has 13 years of experience working on climate adaptation at the National Oceanic and Atmospheric Administration (NOAA) Climate Science Program Office as a manager for climate research applications and services.
Climate Change and Its Causes: A Discussion about Some Key Issues
February 26, 2009
Nicola Scafetta (Duke University)
Abstract: A comparison of past and recent studies suggests that the problem of climate change is complex, as it is evident. Several key issues remain open and their solution may drastically change our understanding of the phenomenon. The crucial issue is: how is it possible to address a problem such a climate change where several crucial physical ingredients are still severely uncertain? In particular, some of the key issues he will address are: a) Did the total solar activity remain constant (as the IPCC and PMOD claim) or increase (as ACRIM claims) since 1980? b) Was the preindustrial temperature almost constant (The Hockey Stick graph) or did it experience a large change? c) What is the contribution of the GHG forcing on climate change, was it overestimated in some important past publications and might this have contributed to shape and bias the following debate? It is evident that solving the above issues in one way or in another is crucial for correctly interpreting climate change. He will propose a solution based on minimal physical assumptions that appear to have been confirmed by a large scientific empirical and theoretical literature. This solution suggests that a significant portion of climate change is natural and linked to changes of solar activity. He will also address the puzzling possibility that climate change might be partially driven by an additional natural forcing different from the radiative one that has not been identified yet. Finally, he will use these findings to attempt a climate prediction about the 21st century and discuss the possibility of an imminent global cooling.
Dr. Scafetta is a research scientist in the Department of Physics at Duke. He has about 40 papers in peer reviewed journals and two books in preparation.
Natural and Anthropogenic Influences on Earth’s Surface Temperature
January 28, 2009 (10:00 to 11:30 am)
Judith Lean (U.S. Naval Research Laboratory)
Abstract: There are many sources of climate variability, including anthropogenic gases, the El Nino Southern Oscillation (ENSO), volcanic aerosols and solar activity. Deciphering their concurrent impacts on Earth’s surface temperature is difficult because the solar activity cycle and volcanic cooling project onto each other, and both project onto ENSO. Longer-term solar changes may also project onto anthropogenic influences in the past century. A multivariate analysis is one approach for quantifying the natural and anthropogenic components of the surface temperature record simultaneously. Such an analysis, using the best available estimates of each together with the observed temperature, enables comparisons of the geographical distributions of surface temperature responses to the individual influences consistent with their global impacts from 1889 to 2006. The combined natural and anthropogenic influences (at appropriate lags) capture 76% of the variance in the monthly global surface temperature record, suggesting that much of the variability arises from processes that can be identified and their impact on the global surface temperature quantified by direct linear association with the observations. The response to solar forcing is quite different from that reported in several papers published recently: solar forcing produces a detectable 11-year cycle of amplitude 0.1K but contributed negligible long-term warming in the past 25 years and 10% of the warming in the past 100 years, not 69% as claimed elsewhere. Zonally averaged responses to both natural and anthropogenic forcings do not increase rapidly from mid to high latitudes, and therefore differ distinctly from those indicated by the IPCC, whose conclusions depended on model simulations. A recent paper co-authored by Dr. Lean on this subject can be found at Judith L. Lean and David H. Rind, "How Natural and Anthropogenic Influences Alter Global and Regional Surface Temperatures: 1889 to 2006, Geophysical Research Letters, Vol. 35, L18701, September 16, 2008. Dr. Lean is a Senior Scientist for Sun-Earth System Research in the Space Science Division of NRL. She is a member of the National Academy of Sciences and the author or co-author of over 100 papers in professional journals.
Global Warming: What Is It All About?
December 9, 2008 (1:30 to 3:00 pm)
Richard Lindzen (MIT)
Abstract: This is the first of three seminars on the science of global warming from widely different viewpoints. While global warming is frequently presented as a single phenomenon that one either believes in or denies, the real situation is, unsurprisingly, much more complex in the presenter's view. There are, in fact, certain aspects of the issue on which a substantial measure of agreement exists: namely, that global mean temperature has increased a few tenths of a degree since the 19th Century, and that increases in atmospheric CO2 have contributed some part of this warming. He examines some approaches to determining exactly how much of observed warming is actually due to anthropogenic greenhouse forcing, and how explicit feedbacks are involved in these results. However, the connection of this warming to catastrophic projections is extremely tenuous in his view. Moreover, proposed mitigation policies have little relevance to warming regardless of the level of warming expected. Understanding these ‘disconnects’ not only helps one to assess the overall situation rationally, but also permits one to see how the issue is being improperly exploited in Dr. Lindzen's view.
Dr. Lindzen is the Alfred P. Sloan Professor of Meteorology at MIT. He is a member of the National Academy of Sciences and has authored or co-authored over 200 professional journal articles.
Human Health Impacts of the and Public Health Responses to Climate Change
November 18, 2008, 2 to 3:30 pm
Kristie L. Ebi (independent consultant with ESS, LLC)
Abstract: Climate change is projected to have far-reaching effects on human health and well-being. Heatwaves and other extreme weather events (e.g., floods, droughts, and windstorms) directly affect millions of people and cause billions of dollars of damage annually. There is a growing consensus that the frequency and intensity of extreme weather events will likely increase over coming decades as a consequence of climate change, suggesting that the associated health impacts also could increase. Indirectly, climate can affect health through affecting the number of people at risk of malnutrition, as well as through alterations in the geographic range and intensity of transmission of vectorborne, zoonotic, and food- and waterborne diseases, and changes in the prevalence of diseases associated with air pollutants and aeroallergens. Climate change has begun to alter natural systems, increasing the incidence and geographic range of some vectorborne and zoonotic diseases. Additional climate change is projected to significantly increase the number of people at risk of major causes of ill health, particularly malnutrition, diarrheal diseases, malaria, and other vectorborne diseases. Climate also can impact population health through climate-induced economic dislocation and environmental decline.
Public health has experience in coping with climate-sensitive health outcomes; the present state of public health reflects (among many other factors) the success or otherwise of the policies and measures designed to reduce climate-related risks. Climate change will make more difficult the control of a wide range of climate-sensitive health outcomes. Therefore, policies need to explicitly consider these risks in order to maintain current levels of control. In most cases, the primary response will be to enhance current health risk management activities. Although there are uncertainties about future climate change, failure to invest in adaptation may leave communities and nations poorly prepared, thus increasing the probability of severe adverse consequences. Equally, mitigation strategies, policies, and measures are needed to rapidly reduce emissions of greenhouse gases, to improve health today and to prevent health impacts in future decades. Policy makers need to understand the potential impacts of climate change, the effectiveness of current adaptation and mitigation policies, and the range of choices available for enhancement of current or development of new policies and measures.
Dr. Kristie L. Ebi is an independent consultant (ESS, LLC) who has conducted research on the impacts of and adaptation to climate change for more than a decade. She has edited three books on climate change and health, and has more than 75 publications.
Global Sea Level Rise
October 16, 2008
Karl Wunsch (MIT)
Abstract: Like many aspects of climate change, the problem of determining, describing, and understanding shifts in "sea level" proves to be far more complicated and interesting than summary sound bites suggest. Something is now known of the spatial patterns of sea level change and they are very complex, showing major regions of falling sea surface over large areas. Although the best estimates of the global average all show a positive rate of rise, partitioning the rise between heating/cooling and the addition/subtraction of fresh water lies at the very edge of modern oceanographic observational and modeling techniques. The eventual societal costs of sea level rise, whether accelerated or stable at present estimated rates, are huge and to a large extent appear inexorable.
The Shape of Things to Come: Why is Climate Sensitivity So Unpredictable (and Who Cares Anyway)?
April 15, 2008 (2:30 pm)
Gerard Roe and Marcia Baker (University of Washington)
Abstract: Underlying all the benefit estimates of global climate change control are the climate's sensitivity to GHG increases; this presentation explored what is currently known about this critical factor.
What kind of information from the climate science community is the most useful for policy makers, and which uncertainties matter most? Constraining climate sensitivity - the long-term increase in global mean temperature expected from the doubling of atmospheric carbon dioxide - has been one of the main benchmark goals of climate science. I will review the various disagreements over what future progress might be anticipated, as well as the debate about the extent to which reducing climate sensitivity even matters for any practical decisions on climate policy.
Uncertainties in projections of future climate change have not lessened substantially in past decades. Both models and observations yield broad probability distributions for climate sensitivity, with small but finite probabilities of very large increases. We show that the shape of these probability distributions is an inevitable and general consequence of the nature of the climate system. Further, we show that the breadth of the distribution and, in particular, the probability of large temperature increases are relatively insensitive to decreases in uncertainties associated with the underlying climate processes.