The amount of greenhouse gases in the atmosphere reached a new record high in 2011, according to a recent report from the World Meteorological Organization (WMO).
Between 1990 and 2011, there was a 30% increase in radiative forcing – the warming effect on our climate – because of carbon dioxide (CO2) and other heat-trapping long-lived gases.
Since the start of the industrial era in 1750, about 375 billion tons of carbon have been released into the atmosphere as CO2, primarily from fossil-fuel combustion, according to the WMO report. About half of this CO2 remains in the atmosphere, with the rest being absorbed by the oceans and terrestrial biosphere.
"These billions of tons of additional carbon dioxide in our atmosphere will remain there for centuries, causing our planet to warm further and impacting on all aspects of life on earth," notes WMO Secretary-General Michel Jarraud. "Future emissions will only compound the situation."
The report focuses on atmospheric concentrations – and not emissions – of greenhouse gases. (Emissions represent what goes into the atmosphere; concentrations represent what remains in the atmosphere after the complex system of interactions among the atmosphere, biosphere and oceans.)
The National Oceanic and Atmospheric Administration's Annual Greenhouse Gas Index, quoted in the WMO report, shows that from 1990 to 2011, radiative forcing by long-lived greenhouse gases increased by 30%, with CO2 accounting for about 80% of this increase. Total radiative forcing of all long-lived greenhouse gases was the CO2 equivalent of 473 parts per million in 2011, the report adds.