The levels of gases in the atmosphere that drive global warming increased to a record high in 2012.
According to the World Meteorological Organization (WMO), atmospheric CO2 grew more rapidly last year than its average rise over the past decade.
Concentrations of methane and nitrous oxide also broke previous records
Thanks to carbon dioxide and these other gases, the WMO says the warming effect on our climate has increased by almost a third since 1990.
The WMO's annual greenhouse gas bulletin measures concentrations in the atmosphere, not emissions on the ground.
Carbon dioxide is the most important of the gases that they track, but only about half of the CO2 that's emitted by human activities remains in the atmosphere, with the rest being absorbed by the plants, trees, the land and the oceans.