Environment Counts | WMO reports record 2013 Greenhouse Gas Levels :
The World Meteorological Association (WMO) released its annual report on The State of Greenhouse Gases in the Atmosphere in September 2014. The report is based on global observations through 2013 under the Global Atmosphere Watch (GAW) Programme.
GAW coordinates observations of the most important contributors to climate change: long-lived greenhouse gases (LLGHG).
The report states that â€œCarbon dioxide is the single most important anthropogenic greenhouse gas in the atmosphere, contributing ~65% to radiative forcing by LLGHGs. It is responsible for ~84% of the increase in radiative forcing over the past decade and ~83% over the past five years.â€
The latest analysis of observations from the GAW Programme shows that the globally averaged mole fractions of CO2, CH4 and N2O reached new highs in 2013, with CO2at 396.0Â±0.1 ppm, CH4 at 1824Â±2 ppb and N2O at 325.9Â±0.1 ppb. These values constitute, respectively, 142%, 253% and 121% of pre-industrial (before 1750) levels. The atmospheric increase of CO2 from 2012 to 2013 was 2.9 ppm, which is the largest year to year change from 1984 to 2013. The report states, references to pre-industrial times (usually 1750) are from ice cores.
The State of Greenhouse Gases in the Atmosphere – Based on Global Observations through 2013 The World Meteorological Association. September, 2014.