Greenhouse Gas Bulletin

Context (TH): The World Meteorological Organisation (WMO) has released its annual Greenhouse Gas Bulletin, published since 2004, which assesses global surface concentrations of greenhouse gases in comparison with the previous year and pre-industrial levels.

Key Findings of the Report:

• Concentration Levels:
  • The globally averaged surface concentrations of CO2, methane (CH4), and nitrous oxide (N2O) have reached 151%, 265%, and 125% of pre-industrial levels, respectively.
• Carbon Dioxide (CO2):
  • Contribution to Warming: CO2 is responsible for about 64% of the warming effect, primarily due to fossil fuel combustion, cement production, and influences from the El Niño–Southern Oscillation.
• Methane (CH4):
  • Warming Effect: Methane contributes around 16% of the warming effect from long-lived greenhouse gases.
  • Emission Sources: Approximately 40% of methane emissions come from natural sources, with the remaining 60% from human activities. Increased methane levels have been linked to emissions from wetlands and agriculture.
• Nitrous Oxide (N2O):
  • Impact: N2O accounts for about 6% of the radiative forcing caused by long-lived greenhouse gases.
  • Emission Sources: Emissions are sourced 60% from natural origins (like oceans and soils) and 40% from human activities, including biomass burning and fertilizer use.
• Radiative Forcing:
  • From 1990 to 2023, radiative forcing due to long-lived greenhouse gases has risen by 51.5%, with CO2 contributing around 81% of this increase.
  • Radiative forcing indicates the magnitude of the energy imbalance in the atmosphere, measured in watts per square meter, and represents the influence of these gases on climate warming.