Figure 1 - Burning embers.
From the following article
Timothy M. Lenton & Hans Joachim Schellnhuber
Nature Reports Climate Change , 97 - 98 (2007) Published online: 22 November 2007
doi:10.1038/climate.2007.65

Potential policy-relevant tipping elements that could be triggered by global warming this century, with shading indicating their uncertain thresholds. For each threshold, the transition from white to yellow indicates a lower bound on its proximity, and the transition from yellow to red, an upper bound. The degree of uncertainty is represented by the spread of the colour transition.
