The Global Atmosphere Watch (GAW) programme of the World Meteorological Organization(WMO) promotes systematic and reliable observations of the global atmospheric environment. Of the long-lived greenhouse gases that are directly affected by anthropogenic activities, carbon dioxide (CO2) has the largest total radiative effect, followed by methane (CH4), nitrous oxide (N2O) and chlorofluorocarbons (CFCs). Reliable long-term estimates of sources and sinks appropriate to particular emission management scenarios require very high accuracy and precision observations of the abundance and the vertical distribution of CO2 and CH4 as well as their isotopes and related reactive (O3, CO, NOx, SO2, VOC, etc.) gases.

The data are collected and distributed by the World Data Centre for Greenhouse Gases(WDCGG) at the Japan Meteorological Agency. The GAW Scientific Advisory Group for Greenhouse Gases (SAG-GHG) advises on the programme development. GAW issues the annual Greenhouse Gas Bulletin, which reports on the latest trends and atmospheric burdens of the most influential, long-lived greenhouse gases, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), as well as a summary of the contributions of the lesser gases.
GAW Greenhouse Gas Research