Over a year ago I was treated to a presentation on the likelihood of the earth system flipping out of sync and moving into a new regime. To be a bit more precise, these are termed tipping points, and finally, I noticed that the paper has supposedly come out in PNAS Early Edition, but can’t seem to spot it yet. The tipping points that the authors look at are (taken from here):
The authors used expert knowledge to evaluate the probabilities of a tipping point occurring, rather than engage in fairly intensive crystal ball modelling approaches. Someone once told me that you gather expert knowledge when you don’t have any solid data, which is probably true, but nonetheless should not detract from the value of this approach.
I seem to remember being quite horrified by the probabilities of some of these tipping points. For our study, the probability of Amazon dieback is highly relevant, and if memory serves me (which it rarely does) the probabilities were over 30%. For many other tipping points the probabilities were also alarmingly high. These really are the doomsday scenarios that Hollywood love, and they are brought into the realm of distinct reality by this study.
Note: Now found an online version of the article here thanks to Island of Doubt.
Article citation: Lenton, T. M., Held, H., Kriegler, E., Hall, J. W., Lucht, W., Rahmstorf, S. and Schellnhuber, H. J. (2008). Tipping elements in the Earth’s climate system. Proceedings of the National Academy of Sciences, Online Early Edition. February, 2008.
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