Collaborative Research: Arctic Temperature Amplification during the Middle Pliocene (ArcAMP): Assessing the interaction among feedback mechanisms

University Corporation For Atmospheric Res, Boulder CO

Investigators

Abstract

The Arctic is currently warming faster than anywhere else on Earth. This so-called Arctic Amplification of surface temperatures is well documented; however, the various feedback mechanisms and how they co-operate to amplify arctic temperatures remain uncertain. Important clues for solving some of these fundamental climate questions regarding arctic amplification may be found during the Pliocene (2.6 to 5.3 million years ago), which is the last time in Earth's history when atmospheric CO2 concentrations were comparable to modern concentrations of about 400 ppm, and yet arctic temperatures were 10 to 20 degrees C warmer. This project investigates the interactions among terrestrial feedback mechanisms during the Pliocene and their role in amplifying arctic surface temperatures. In particular, it investigates the net radiative forcing of vegetation albedo, atmospheric water vapor, and black carbon emitted from fire on the arctic climate system. This will be accomplished by conducting high-resolution reconstructions of past temperatures, atmospheric CO2, and fire for three high arctic sites that have been recently well-dated by terrestrial cosmogenic nuclides. To disentangle how these processes may have been interacting to amplify arctic temperatures, a series of climate experiments will be conducted using the Community Earth System Model.