Modeling Seasonal and Regional Patterns of Abrupt Climate Change

University Of Colorado At Boulder, Boulder CO

Investigators

Abstract

ABSTRACT WHITE OPP-0519512 A better understanding of the Earth's natural climatic variability, and abrupt climate change, is of crucial importance as global climate change proceeds in the 21st century. Two recent reports, the intergovernmental Arctic Council's Arctic Climate Impact Assessment, and the National Academy's Abrupt Climate Change: Inevitable Surprises, have noted the importance of abrupt climate change as a driver of policy making, as well as the need to better model the triggers and impacts of such climate shifts. Abrupt climate changes can be very large, especially in high latitudes (e.g., greater than 10 degrees C mean annual temperature changes, doubling of precipitation), and very fast, (e.g., dust concentration and precipitation changes in a few years, temperature changes in a few decades), and thus pose a serious challenge to successful adaptation to climate change, and instead make mitigation more attractive. However, as yet, scientists cannot predict when an abrupt climate change will occur, although it is known that they are relatively common in the paleo- environmental record, nor do scientists completely understand how they start, spread globally and regionally, and end. Intellectual Merit The aim of this research is to bring together high-resolution proxy records of abrupt climate change primarily from the Arctic and the northern hemisphere, but globally as well, with a sophisticated, global atmosphere-ocean climate model (ECBilt-CLIO) capable of reproducing abrupt climate changes, in order to improve our understanding of how such climate shifts are triggered, propagate, end, and are recorded in paleo-environmental archives. Many issues regarding the pattern and amplitude of these massive climatic shifts recorded in polar ice cores and marine sediments remain elusive, and interpretations are often based on simple conceptual models and theories. The Principal Investigators believe that the time is right to begin more sophisticated modeling of these events, both because the models capable of studying such events are much improved, and also because the data base of these events, particularly from Greenland ice cores, has improved sharply over the past few years. Specifically, this proposal seeks to address several aspects of abrupt climate change, including the synchroneity of changes in different regions of the northern hemisphere and the world, the variable amplitudes of the events, the differing sequence of climatic events going into and out of abrupt climate changes, the seasonality of the events, the role of variable arctic sea ice extents, and the influence of variable levels of solar insolation on the events. Paleo-data reveals that not all abrupt climate changes are created equal; they have the different amplitudes, sequences of changes, an d extent. This work seeks to exploit these differences, and using the climate model, improve the understanding of how the events begin (or not begin), express themselves and end. Broader Impacts As noted above, abrupt climate change looms as one of the great challenges for the future, and policy makers need better input on this issue than science can give them today. This is also a natural addition to existing undergraduate and graduate courses in the environment, and the investigators will use the existing NSF-IGERT program at Colorado to take what is learned from this proposal and feed it into courses. This project will also form the basis of an Honor's Thesis, as well as a research project in the UCAR SOARS program, which promotes the participation of underrepresented groups in science.