E. Kriegler et al., PNAS 2009, Imprecise probability assessment of tipping points in the climate system

Proceedings of the National Academy of Sciences, published online before print March 16, 2009; doi: 10.1073/pnas.0809117106

Imprecise probability assessment of tipping points in the climate system

 Elmar Kriegler^a,^b, Jim W. Hall^c,^d, Hermann Held^a, Richard Dawson^c,^d and Hans Joachim Schellnhuber^a,^e,^f

Edited by William C. Clark, Harvard University, Cambridge, MA, and approved February 2, 2009 (received for review September 16, 2008).

Abstract

Major restructuring of the Atlantic meridional overturning circulation, the Greenland and West Antarctic ice sheets, the Amazon rainforest and ENSO, are a source of concern for climate policy. We have elicited subjective probability intervals for the occurrence of such major changes under global warming from 43 scientists. Although the expert estimates highlight large uncertainty, they allocate significant probability to some of the events listed above. We deduce conservative lower bounds for the probability of triggering at least 1 of those events of 0.16 for medium (2–4 °C), and 0.56 for high global mean temperature change (above 4 °C) relative to year 2000 levels.

Link to abstract:  http://www.pnas.org/content/early/2009/03/17/0809117106

Link to full, free, open-access article:  http://www.pnas.org/content/early/2009/03/17/0809117106.full.pdf+html