Nature notes that “Greenhouse gases hit modern-day highs.”
So, uh, why is it so cold?
Atmospheric concentrations of greenhouse gases reached new highs in 2007, according to the most recent analysis by the World Meteorological Organization (WMO).
Concentrations of carbon dioxide, methane and nitrous oxide — which together contribute 88% of the anthropogenic global-warming effect — were last year 37%, 156% and 19% above pre-industrial levels, respectively.
Since 1990, total radiative forcing — the re-radiation of heat back towards Earth’s surface — by all long-lived heat-trapping gases has increased by 24%, the WMO reports. In 2007, the average concentration of carbon dioxide rose to 383 parts per million, an increase of 0.5% from 2006. Methane and nitrous oxide concentrations also rose, reaching new highs of 1,789 and 321 parts per billion. The increases are in line with the Intergovernmental Panel on Climate Change’s predictions for greenhouse-gas concentrations in a world experiencing rapid economic growth.