SOIL CARBON AND CLIMATE CHANGE NEWS
From Kansas State University's:
Consortium for Agricultural Soils Mitigation of Greenhouse Gases (CASMGS)
Charles W. Rice, K-State Department of Agronomy, National CASMGS Director
(785) 532-7217 firstname.lastname@example.org
Scott Staggenborg, K-State Department of Agronomy (785) 532-7214 email@example.com
Steve Watson, CASMGS Communications (785) 532-7105 firstname.lastname@example.org
December 23, 2009
Main Greenhouse Gases Reach Highest
Level Ever Since Pre-Industrial Time
Levels of most greenhouse gases continue to increase. In 2008, global concentrations of carbon dioxide, methane, and nitrous oxide, which are the main long-lived greenhouse gases in the atmosphere, have reached the highest levels recorded since pre-industrial times, according to the World Meteorological Organizationís 2008 Greenhouse Gas Bulletin. Since 1990, the overall increase in radiative forcing caused by all long-lived greenhouse gases is 26% and the increase was 1.3% from 2007 to 2008. These latest figures confirm the continued trend of rising atmospheric burdens of greenhouse gases since 1750.
WMO, through its Global Atmosphere Watch (GAW) Program, coordinates the observations of greenhouse gases in the atmosphere through a network of stations located in more than 50 countries.
The globally averaged mixing ratio of carbon dioxide (CO2) in 2008 was 385.2 ppm, with an increase of 2.0 ppm from the previous year. CO2 is the most important human-emitted greenhouse gas in the atmosphere, contributing 63.5% to the increase in overall radiative forcing since 1750. Since 1750, atmospheric CO2 has increased by 38%, primarily because of emissions from combustion of fossil fuels, deforestation, and land use change.
The globally averaged mixing ratio of methane (CH4) in 2008 was 1797 ppb, which means an increase of 7 ppb from the previous year. While the concentration of CH4 was stable for seven years (from 1999 to 2006), both 2007 and 2008 show a significant increase. Methane contributes 18.2% to the increase in overall global radiative forcing since 1750. 60% of CH4 emissions come from anthropogenic sources such as ruminants, rice agriculture, fossil fuel exploitation, landfills and biomass burning. Before the industrial era, atmospheric methane was about 700ppb. Increasing emissions from anthropogenic sources are responsible for the 157% increase in the CH4 concentration since 1750.
The globally averaged mixing ratio of nitrous oxide (N2O) in 2008 was 321.8 ppb, 0.9 ppb higher than in 2007, and 19% above the pre-industrial level. N2O contributes 6.2% to the increase in the overall global radiative forcing since 1750. The atmospheric abundance of N2O prior to industrialization was 270 ppb. N2O is emitted into the atmosphere from natural and anthropogenic sources, including oceans, soil, biomass burning, fertilizer use and various industrial processes.
-- World Meteorological Organization, Press Release No. 868, Nov. 23, 2009