Greenhouse Gas Bulletin

About Greenhouse Gas Bulletin:

• It has been published annually since 2004 by the World Meteorological Organization.
• It shows globally averaged surface mole fractions for Carbon Dioxide (CO2), Methane (CH4) and Nitrous Oxide (N2O) and compares them with the mole fractions during the previous year and with ‌preindustrial levels.
• It also provides insights into the change in radiative forcing by long-lived GHGs (LLGHGs) and the contribution of individual gases to this increase.
• It is one of WMO’s flagship publications released to inform the UN Climate Change conference (COP).

Highlights of the Bulletin

• The globally averaged surface concentration of Carbon Dioxide reached 420 parts per million (ppm), Methane 1934 parts per billion and Nitrous Oxide9 parts per billion (ppb) in 2023.
• Carbon Dioxide is the single most important greenhouse gas in the atmosphere related to human activities, accounting for approximately 64 percent of the warming effect on the climate, mainly because of fossil fuel combustion and cement production,
• The long-term carbon dioxide increase is due to fossil fuel combustion, but there are year-to-year variations due to the El Nino–Southern Oscillation, which impacts photosynthetic carbon dioxide uptake, respiratory release, and fires.
• Methane is a powerful greenhouse gas which remains in the atmosphere for about a decade. Methane accounts for about 16 percent of the warming effect of long-lived greenhouse gases.
• Nitrous oxide, an ozone depleting chemical, accounts for about 6 per cent of the radiative forcing – the warming effect on the climate -- by long-lived greenhouse gases.
• From 1990 to 2023, radiative forcing — the warming effect on our climate — by long-lived greenhouse gases increased by 51.5%, with CO2 accounting for about 81 per cent of this increase.