Are there tipping points in the Earth’s climate system?
There are a number of tipping points in the climate system, based on understanding of its non-linear dynamics, and as revealed by past abrupt climate changes and model behavior (Pitman and Stouffer 2007; Schellnhuber 2009). Some models pass tipping points in future projections, and recent observations show abrupt changes already underway in the Arctic. Recent work has identified a shortlist of nine potential policy-relevant tipping elements in the climate system that could pass a tipping point this century and undergo a transition this millennium under projected climate change (Lenton et al. 2008). These are shown with some other candidates in Figure 18. Which ones are of the greatest concern? How has this been assessed? The tipping points of greatest concern are those that are the nearest (least avoidable) and those that have the largest negative impacts. Generally, the more rapid and less reversible a transition is, the greater its impacts. Additionally, any amplifying feedback to gl
