The amount of greenhouse gas in the globe's atmosphere hit a record high in 2012, the United Nations said on Wednesday.
Carbon dioxide, which makes up 80 percent of greenhouse gas levels, was higher in 2012 than its average growth rate over the last decade, the U.N. World Meteorological Organization (WMO) said in an emailed bulletin.
"The observations from WMO’s extensive Global Atmosphere Watch network highlight yet again how heat-trapping gases from human activities have upset the natural balance of our atmosphere and are a major contribution to climate change,” Michel Jarraud, secretary-general of the meteorological organization, said in a statement.
Roughly 60 percent of methane in the atmosphere comes from human activities, according to the bulletin. Methane levels have steadily increased since 2007 after a brief period of leveling-off.
"Limiting climate change will require large and sustained reductions of greenhouse gas emissions. We need to act now, otherwise we will jeopardize the future of our children, grandchildren and many future generations,” Jarraud said. “Time is not on our side."
Next week, the U.S. and more than 190 nations will meet in Warsaw, Poland, for climate change negotiations, starting Nov. 11. Countries hope to make progress on a climate agreement expected to be finalized by 2015.
Reports are less than optimistic. Senior attorney for the Center for International Law Alyssa Johl said on Monday that if policymakers come to a legally binding agreement for 2015 it will not be enough to mitigate climate change.
"Short term action that is not driven by a political agenda is needed," Johl said.