The report from the U.N. Environment Program says there is a considerable shortfall between what science says is necessary to hold down temperature rise and what governments have pledged to achieve, the BBC reported Tuesday.
"There is a gap between the science and current ambition levels," said UNEP Executive Director Achim Steiner.
The report comes just days before the opening of this year's climate summit in Cancun, Mexico, following last year's summit in Copenhagen, Denmark, where world governments made their climate pledges under the Copenhagen Accord.
"The level of effort expressed in the Copenhagen Accord in terms of emission reduction is almost three times higher than what was achieved with the Kyoto Protocol, which is by itself very positive and shows some improvement," said Mexican Environment Secretary Juan Rafael Elvira, who will host this year's talks.
"However, we need to formalize and, if possible, increase current pledges and translate them into commitments for developed countries and into acknowledged actions for developing countries," he said.
Tom Brookes from the European Climate Foundation urged all countries to recognize the gap between their stated desires to keep temperature rises down and the pledges they have made on curbing emissions.
"As well as making the kind of headline pledge they made for Copenhagen, the time is right for them now to be working out in detail how they are going to meet those pledges," he said.