WMO REPORT ON GHGs (Syllabus: GS Paper 3 – Env and Eco)

Context: Recently, the World Meteorological Organisation (WMO) released a GHG bulletin revealing that concentrations of greenhouse gases (GHG), which trap heat in the Earth's atmosphere, rose to record levels in 2022.

• The rise in concentrations of GHGs is mainly due to the use of fossil fuels for various human activities.

Greenhouse Gases (GHGs)

• About: A greenhouse gas is a gas that absorbs and emits infrared radiation. 

o They absorb infrared energy (heat energy) emitted from the earth’s surface and reradiates it back to the earth’s surface. 

o They contribute to the Greenhouse Effect, which is the resultant heating effect.

• Most abundant greenhouse gases in Earth’s atmosphere: Water vapour, Carbon dioxide, Methane, Nitrous oxide, Ozone, Chlorofluorocarbons, Hydrofluorocarbons.

o Among the greenhouse gases, only water vapour can absorb both incoming (UV) and outgoing (infrared) radiation.

o Oxides of Nitrogen with general formula NOx - NO, NO2 - Nitrogen oxide, Nitrogen dioxide etc. are global cooling gases.

• Other GHGs: Carbon monoxide, fluorinated gases, chlorofluorocarbons (CFCs), black carbon (soot), and brown carbon.
• Carbon monoxide (CO): It is not considered a direct greenhouse gas, mostly because it does not absorb terrestrial thermal IR energy strongly enough. But CO is able to modulate the production of methane and tropospheric ozone.
• Global Initiative to fight GHGs: Kyoto protocol, Paris Agreement, SDG (2030) etc.