Abrupt Climate Change
Traditionally, most climate change analyses have assumed any impacts would emerge gradually. But in recent years, evidence has grown that the climate system can exhibit abrupt changes that emerge rapidly once the system passes some threshold or tipping point. Including the potential for such abrupt changes in policy analyses of climate change can be difficult, however, for at least two reasons. First, the resulting discontinuities can make policy models more difficult to solve. Second, the likelihood of any abrupt change can be difficult to estimate.
In this project we have been advancing and using robust decisionmaking methods to better address these issues. In particular, we have examined the ability alternative observation systems to provide actionable warning of any oncoming change in the North Atlantic meridional overturning circulation, evaluated the costs and benefits of early action and optimal risk reduction strategies in the face of uncertain climate thresholds, and estimated the benefits and risks of carbon sequestration technologies as a response to potential abrupt climate changes.
This research has advanced the ability to address this type of uncertainty in climate change policy and has provided some valuable policy insights. In addition, we have used the results of these analyses to support our judgment and decision making laboratory experiments that assess how individuals respond to different characterizations of deep uncertainty.
Published Research (in reverse chronological order)
Managing the Risk of Uncertain Threshold Responses: Comparison of Robust, Optimum, and Precautionary Approaches
Lempert, Robert J. and Myles T. Collins. Risk Assessment, Vol 27, No 4, 2007, p. 1009-1026.
Early Detection of Changes in the North Atlantic Meridional Overturning Circulation: Implications for the Design of Ocean Observation Systems — 2007
Keller, K., C. Deutsch, M. G. Hall and D. F. Bradford. Journal of Climate, Volume 20, Issue 2, January 2007, pp. 145-157.
Economically Optimal Risk Reduction Strategies in the Face of Uncertain Climate Thresholds — 2007
McInerney, D. and K. Keller. Climate Change, Published online, January 2007.
Submitted or In Press (in alphabetical order)
Detecting Potential Changes in the Meridional Overturning Circulation at 26°N in the Atlantic — 2007
Baehr, J., K. Keller, and J. Marotzke
To be available at: http://dx.doi.org/2010.1007/s10584-10006-19153-z, Climate Change
The Dynamics of Learning about a Climate Threshold — 2007
Keller, K. and D. McInerney
Access Draft PDF at Climate Dynamics
Global optimization of an Observing System Design for the North Atlantic Meridional Overturning Circulation — 2007
Baehr, J., D. McInerney, K. Keller, and J. Marotzke
Access Draft PDF at Journal of Atmospheric and Oceanic Technology
Managing the Risks of Climate Thresholds: Uncertainties and Needed Information
Keller, K., G. Yohe, and M. Schlesinger
Oxygen Observations Improve the Detection Capabilities of an Ocean Observation Array — 2007
Brennan, C., R. Matear, and K. Keller
Access Draft PDF at Journal of Geophysical Research – Oceans
The Regrets of Procrastination in Climate Policy — 2007
Keller, K., A. Robinson, D. F. Bradford, and M. Oppenheimer
Access Draft PDF (Environmental Research Letters)
Robust Strategies in the Face of Uncertain Climate Thresholds — 2007
McInerney, D., R. Lempert, and K. Keller
What is the Economic Value of Information About Uncertain Climate Thresholds?
K. Keller, S.-R. Kim, J. Baehr, D. F. Bradford, and M. Oppenheimer
Access Draft PDF as a chapter in Integrated Assessment, The State of the Art
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