World on a Trajectory to 6C Warming Without Copenhagen

A group of scientists, led by Professor Corinne Le Quéré at the University of East Anglia, have called for urgent action at the UN climate change talks in Copenhagen to avert a catastrophic 6C rise in average global temperature. Professor Le Quéré and colleagues from the British Antarctic Survey published their results, part of the Global Carbon Project, in Nature Geoscience. The Guardian this morning describes the study as ‘the most comprehensive analysis to date of how economic changes and shifts in land use have affected carbon dioxide concentrations’.

The scientists suggest that the global trend, with emissions rising by 29% in the past decade, is towards 6C of warming before 2100. To limit a rise in temperature to 2C, a target favoured by policy-makers as necessary to avoid ‘dangerous climate change’, emissions would have to peak between 2015 and 2020 and then fall to one tonne per capita globally by 2050. At present the average British citizen is responsible for approximately 9.3 tonnes of carbon emissions per annum. A firm agreement at the Copenhagen summit is therefore vital, they say.

The scientists estimated how much carbon dioxide is being absorbed by forests, oceans and soil. They conclude that these natural carbon sinks are becoming less effective; absorbing 55% of carbon emissions now, compared to 60% 50 years ago. These results are however disputed by Dr Wolfgang Knorr at the University of Bristol, who published an analysis of similar data in Geophysical Research Letters showing that carbon sinks had not noticeably changed. Professor Le Quéré suggests that her team’s data is more robust, using monthly, rather than annual data on carbon dioxide levels.

Both teams of scientists agree that an improved understanding of land and ocean carbon sinks is crucial, with sinks holding a major influence in determining links between man-made greenhouse gas emissions and the atmospheric concentration of carbon dioxide.

Original article: Global temperatures will rise by 6C by the end of the century, say scientists