Climate change is happening faster and on a broader scale than the world's scientists projected in 2007, according to a new report released Thursday by the United Nations Environment Program.

WASHINGTON — Climate change is happening faster and on a broader scale than the world's scientists projected in 2007, according to a new report released Thursday by the United Nations Environment Program.

The new overview of global warming research, aimed at marshalling political support for a new international climate pact by the end of the year, highlights the extent to which recent scientific assessments have outstripped the predictions issued by the Nobel Prize-winning U.N. Intergovernmental Panel on Climate Change two years ago.

That report declared evidence of human-generated warming in the last half-century was "unequivocal," and would change the planet dramatically by 2100 unless greenhouse gas emissions drops sharply by 2050.

Achim Steiner, UNEP's executive director, told reporters at the National Press Club Thursday that the new report aims to update the IPCC's finding to reflect both new physical evidence and a more sophisticated understanding of how earth systems work.

"With every day that passes the underlying trends that science has provided is ... of such a dramatic nature that shying away from a major agreement in Copenhagen will probably be unforgivable, if you look back in history at this moment," Steiner said. Steiner noted that since 2000 alone, the average rate of melting at 30 glaciers in nine separate mountain ranges has doubled compared to the rate during the previous two decades.

"These are not things that are in dispute in terms of data," he said. "They are actually physically measurable."

Other findings include the fact that sea level might rise by as much as six feet by 2100 instead of 1.5 feet as the IPCC had projected, and the Arctic may experience a sea-ice summer by 2030, rather than by the end of the century.

Robert Correll, who chairs the Climate Action Initiative and contributed to the UNEP report, said even if you take into account all the pledges industrialized and developed countries have made to cut their greenhouse gas emissions, global temperature would likely rise by 8 degrees Fahrenheit.

That's two times higher than what scientists and world policy-makers have identified as the upper limit of warming the world can afford in order to avert catastrophic climate change. "We don't want to go there," Correll said, adding that global carbon emissions are still on the upswing. "It's accelerating, We're not going in the right direction."

Michael MacCracken, one of the scientific reviewers for the IPCC and the chief scientist for climate change programs at The Climate Institute, said if either the developed nations cut their emissions by half and the developing countries continued on their current path, or vice versa, the world would still experience significant warming by 2050. "We face a situation where basically everybody has to do everything they can," MacCracken said.