Global carbon emission reduction strategies could fall short of a major climate change benchmark, according to a study published Monday.
Even if major governments stick to their current carbon emissions goals, the report says it may not be possible to keep the average global surface temperature from rising more than 2 degrees celsius.
Governments have already begun announcing their emission reduction targets ahead of a major United Nations climate conference in Paris later this year. The Obama administration hopes to cut U.S. carbon emissions by 26 to 28 percent of 2005 levels by 2030; European Union governments want to cut their collective emissions by 40 percent over 1990 levels and China has said its emissions will peak by 2025.
Those three targets, taken together with other nations' reduction goals, would lead to at least 57 gigatons (each gigaton being one billion metric tons) of carbon dioxide emissions in 2030, according to the researchers. But United Nations reports have previously estimated that emissions should be much lower than that for even a 50 percent chance of keeping the temperature increase below the 2-degree mark.
“It seems likely that there will still be a significant gap between aggregate national intentions and a pathway that is consistent with avoiding global warming of more than 2 degrees celsius,” the researchers, from the Grantham Research Institute on Climate Change and the Environment, wrote.
The report said the goals represent “measurable progress” over current trends, but that to meet the 2-degree goal, countries should work to increase their reduction targets both before and after this year's climate talks.
“The magnitude of the gap between current intentions and the international target of limiting global warming to no more than 2 degrees celsius clearly shows that an international agreement in Paris will have to include dynamic mechanisms for the assessment of progress and the raising of ambitions,” the researchers wrote.