Carbon reduction targets pledged as part of international climate negotiations may be sufficient to put the world on a path that gives a reasonable chance of limiting global temperature rise below two degrees Celsius, a new report has found.
The findings, which were published on Sunday, introduce a note of optimism at the beginning of climate talks in Copenhagen. Previous analysis had shown rich countries' pledges were well below the recommended 25-40% emission cut.
The report conducted by British economist Sir Nicholas Stern and two British research centres shows global emissions in 2020 should be no more than 44 gigatonnes (Gt) of CO2 equivalent. The findings are in line with IPCC conclusions, it says.
Targets and actions proposed by industrialised and developing countries ahead of December's summit would take the world to around 46 Gt of CO2 equivalent in 2020, leaving a gap of 2 Gt to fall into line with the report's "climate responsible" trajectory.
Rich countries' emissions would be 15.7 Gt, according to a "high intentions" scenarios. This means the EU would reduce its emissions by 30% relative to 1990 levels. The US and Japan would cut their emissions by 3% and 25% respectively.
Developing nations would emit 28.9 Gt of CO2, based on actions and targets pledged by countries including China, India, Brazil and Indonesia. Total emissions in the international aviation and maritime sectors would be 1.3 Gt.
However, these estimates "rely on countries being satisfied that the conditions are met for them to reach high targets and, in particular, adequate support being provided to developing countries," according to the report.
The report also assumes that a system of rules on how to account for emissions from land use, land-use change and forestry (LULUCF) activities is in place. This would avoid double counting of emission reductions through carbon offsets.
The Stern report was published by the Centre for Climate Change Economics and Policy and the Grantham Research Institute on Climate Change and the Environment in the UK in collaboration with the UN's environment programme (UNEP).Follow Up: