The Climate Bonus

Notes

1 Introduction

1 The two degree target refers to the increase since pre-industrial times, generally taken to be around the year 1750. Since then, temperatures have already risen by 0.6^oC.

2 The IPCC Fourth Assessment Report (IPCC, 2007) predicts that at 450ppm, there would be a 50 per cent chance of avoiding a 2^oC rise; and at 400ppm, there would be a 66–90 per cent chance (for an explanation, see EU Climate Change Expert Group, 2008, p. 28). But Hansen et al., 2008 call for the 450ppm target to be revised to 350ppm, based on new analysis of climate feedback effects such as release of methane from melting permafrost. For comparison, pre-industrial concentrations were around 280ppm.

3 The average atmospheric concentration of CO₂ during 2009 ...