The agreement is extremely welcome. However, we should also be cautious. It is clear that the 1C temperature rise over pre-industrial levels that we have seen so far has triggered a whole range of effects including melting of mountain glaciers, significant sea-level rise, devastating droughts, and flooding. These effects are likely to get much worse with even modest future increases. Keeping temperatures to manageable levels also assumes that we know what the precise link is between atmospheric greenhouse gas concentrations and the global temperature response. We don’t know this, nor the nature and strength of natural feedbacks in the climate system that might drive future warming.
Stephen Harrison, University of Exeter
