How do global climate feedbacks differ across timescales?

Abstract:

The strength of large scale atmospheric feedbacks (in particular those due to water vapour, clouds, lapse rate and surface albedo) determine the climate ‘sensitivity’ – the magnitude of the global response to greenhouse gas forcing. Understanding and evaluating climate change feedbacks remain critical tasks for quantifying projection uncertainty, assessing confidence in models and ultimately narrowing the range of future projections.

Recent research suggests that global scale radiative feedbacks operate across a very broad range of timescales. For example seasonally, feedbacks act to amplify the annual cycle of temperature, as suggested by both models and observations. What can the strength and structure of feedbacks at ‘shorter’ timescales tell us about climate change feedbacks?

This study addresses this issue by examining the strength and structure of water vapour, lapse rate, surface albedo cloud and temperature feedbacks operating at seasonal, interannual and longer timescales in CMIP3 and CMIP5 models, and comparing them with climate change feedbacks. Implications for both the understanding and evaluation of climate change feedbacks from shorter timescale variability and response will be discussed.