The melting of Antarctic and Greenland ice sheets is accelerating and may trigger faster sea level rise than predicted, according to leaked details of the forthcoming Intergovernmental Panel on Climate Change report.

Greenland's ice added six times more to sea levels in the decade through 2011 than in the prior 10 years, according to details of a draft 2200-page study by the UN agency, obtained by Bloomberg.

Greenland's rate of ice melt has increased rapidly. Credit:Getty Images

The Antarctic experienced a five-fold increase, prompting the UN to raise its forecast for how much the two ice sheets would add to Earth's oceans by 2100.

The leak comes just weeks before the IPCC gathers on September 23 in Stockholm, with the Fifth Assessment Report scheduled to be released four days later. National delegates are expected to wade through 1800 comments to achieve consensus on the important Summary for Policymakers during the event.