IMPACTS : Investigation of the Magnitudes and Probabilities of Abrupt Climate TransitionS
Bill Collins (PI) , Mac Post , Bill Lipscomb , Margaret Torn , Celine Bonfils
LBNL , LANL , PNNL , ORNL
Some of the major risks to society and environment from climate change are posed primarily by abrupt and extreme climate phenomena rather than the continual warming trend. Potential forms of abrupt change include sudden deglaciation, reorganization of the thermohaline circulation system, and widespread melting of permafrost leading to large-scale shifts in the carbon cycle. Abrupt and extreme phenomena can exceed the thresholds for ecological and societal adaptation through either the rapid rate or magnitude of the associated climate change. In this project, we will assess the potential for triggering several types of abrupt climate change (ACC) during the 21st century. Argonne is focussing on the potential for reorganization of the thermohaline or Meridional Overturning Circulation (MOC). The MOC an integral part of the Earth's climate system, as it redistributes heat, freshwater and nutrients throughout the World Ocean. We will be directly calculating which freshwater/heat flux/wind stress/sea-ice perturbations effect the MOC by constructing an adjoint of a global ocean model.