Political attention has increasingly focused on limiting warming to 2 degrees C. However, there is no consensus on both questions Is the 2 degrees C target achievable? and What should be done with this target that becomes increasingly difficult to achieve?. This paper aims at disentangling the points of deep uncertainty underlying this absence on consensus. It first gives simple visualizations of the challenge posed by the 2 degrees C target and shows how key assumptions (on the points of deep uncertainty) influence the answer to the target achievability question. It then proposes an uncertainties and decisions tree, linking different beliefs on climate change, the achievability of different policies, and current international policy dynamics to various options to move forward on climate change. (C) 2012 Elsevier Ltd. All rights reserved.
- CONCENTRATION TARGETS
- CO2 EMISSIONS
Guivarch, C (reprint author), 45Bis Ave Belle Gabrielle, F-94736 Nogent Sur Marne, France.