Chapter 4, Potential for Abrupt Change in the Atlantic Meridional Overturning Circulation, Final Report, Abrupt Climate Change
SAP 3.4: Abrupt Climate Change Chapter 4. The Potential for Abrupt Change in the Atlantic Meridional Overturning Circulation Lead Author: Thomas L. Delworth,* NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ Contributing Authors: Peter U. Clark,* Department of Geosciences, Oregon State University, Corvallis, OR Marika Holland, NCAR, Boulder, CO William E. Johns, Rosenstiel School of Marine and Atmospheric Science, University of Miami, FL Till Kuhlbrodt, Department of Meteorology, NCAS-Climate, University of Reading, United Kingdom Jean Lynch-Stieglitz, School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA Carrie Morrill,* CIRES, University of Colorado/NOAA, Boulder, CO Richard Seager,* Columbia University, Palisades, NY Andrew J. Weaver,* School of Earth and Ocean Sciences, University of Victoria, BC, Canada Rong Zhang, NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ * SAP 3.4 Federal Advisory Committee Member Key Findings The Atlantic Meridional Overturning Circulation (AMOC) is an important component of the Earth’s climate system, characterized by a northward flow of warm, salty water in the upper layers of the Atlantic, and a southward flow of colder water in the deep Atlantic. This ocean circulation system transports a substantial amount of heat from the Tropics and Southern Hemisphere toward the North Atlantic, where the heat is transferred to the atmosphere. Changes in this circulation have a profound impact on the global climate system, as indicated by paleoclimate records. These include, for example, changes in African and Indian monsoon rainfall, atmospheric circulation of relevance to hurricanes, and climate over North America and Western Europe. In this chapter, we have assessed 258 SAP 3.4: Abrupt Climate Change what we know about the AMOC and the likelihood of future changes in the AMOC in response to increasing greenhouse gases, including the possibility of abrupt change.
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