"Recent emissions trends and estimates of the effects of those policies in place and proposed lead to a new estimate that warming is likely to approach 4 degrees Celsius by 2100, significantly above the warming that would result from full implementation of the pledges," the report said. The UN's Intergovernmental Panel on Climate Change has previously set a goal of limiting the increase in the global temperature to no more than two degrees Celsius every century.

The report said the "existing and planned policies are not sufficient for countries to meet these pledges" and current emissions trends are likely to lead to higher emission levels than previously projected. "The continuous global fossil-fuel intensive development of the past decade suggests that high warming levels of 4 degrees Celsius are more plausible than assuming full implementation of current pledges," the Climate Action Tracker said in its latest update, released at the Bonn climate talks.