Brief History of Mankind
Greenhouse gases in the atmosphere at record levels: the World Meteorological Organization (WMO)
The average mixing ratios of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) reached record level in 2009,WMO reported.
- CO2 concentrations ~ 386.8 ppm
- CH4 ~ 1,803 ppb
- N2O ~ 322.5 ppb
These values are greater than the corresponding atmospheric concentrations in pre-industrial times (~1750) by 38%, 158% and 19%, respectively.
In the twenty year period between 1990 and 2009, the combined radiative forcing—the balance between atmosphere’s incoming and outgoing radiation—for all persistent greenhouse gases increased by 27.5%, with CO2 accounting for about 80% of the increase, according to the NOAA Annual Greenhouse Gas Index.
Source: WMO GHG Bulletin
Carbon Dioxide (CO2)
Carbon dioxide is the single most important anthropogenic greenhouse gas in the atmosphere, contributing 63.54 %2 to the overall global radiative forcing. It is responsible for 85% of the increase in radiative forcing over the past decade and 83% over the last five years. For about 10 000 years before the industrial revolution, the atmospheric abundance of CO2 was nearly constant at ~ 280 ppm (ppm = number of molecules of the gas per million molecules of dry air). This level represented a balance among the atmosphere, the oceans and the biosphere. Since 1750, atmospheric CO2 has increased by 38%, primarily because of emissions from combustion of fossil fuels (8.7 Gt carbon in 2008, http://www.globalcarbonproject.org/), deforestation and landuse change. High-precision measurements of atmospheric CO2 beginning in 1958 show that the average increase in CO2 in the atmosphere (airborne fraction) corresponds to ~ 55% of the CO2 emitted by fossil fuel combustion. WMO
Source: WMO GHG Bulletin
Fire Earth 