Collequia - What are climate tipping points, can they be predicted and is the Atlantic current about to collapse?

Abstract

The concept of climate tipping points and feedbacks will be explained and the risk of tipping of the AMOC will be presented.

The Atlantic meridional overturning circulation (AMOC) is a major tipping element in the climate system and a future collapse would have severe impacts on the climate in the North Atlantic region. In recent years weakening in circulation has been reported, but assessments by the Intergovernmental Panel on Climate Change (IPCC), based on the Climate Model Intercomparison Project (CMIP) model simulations suggest that a full collapse is unlikely within the 21st century. Tipping to an undesired state in the climate is, however, a growing concern with increasing greenhouse gas concentrations. Predictions based on observations rely on detecting early-warning signals, primarily an increase in variance (loss of resilience) and increased autocorrelation (critical slowing down), which have recently been reported for the AMOC. Here we provide statistical significance and data-driven estimators for the time of tipping. We estimate a collapse of the AMOC to occur around mid-century under the current scenario of future emissions

About Professor Peter Ditlevsen

Peter Ditlevsen is professor in physics of climate at the Niels Bohr Institute, University of Copenhagen.

He received his PhD in surface science at the Physics Department, DTU in 1991 and had his first postdoc at Lawrence Berkeley Lab, Berkeley, California. Upon returning to Denmark, he was hired as researcher at the Danish Meteorological Institute, initiating his transition into in Meteorology and Climate Science. In 1993 he moved to NBI as postdoc, where he has been ever since, only interrupted by a few stays at NCAR, Boulder and a few other places abroad. He has been teaching just about all elementary physics courses at NBI. Peter Ditlevsen specializes in dynamical systems theory, turbulence and the physics of climate, focusing on predictability, abrupt climate shifts, and tipping points. He also investigates turbulent flows governed by the Navier-Stokes equation, where the lack of a complete theory limits our understanding of chaotic phenomena in both climate science and engineering.