- According to a new study, world needs to target both non-CO2 pollutants and CO2 pollutants to achieve climate targets.
- Global temperatures are likely to exceed 1.5 degrees Celsius over pre-industrial levels by 2035 and 2°C by 2050 if the focus is merely on decarbonisation efforts.
- The Non-CO2 Pollutants include methane, black carbon, hydrofluorocarbons (HFC), tropospheric ozone and nitrous oxide.
- Methane is a potent greenhouse gas. It contributes to the formation of ozone.
- Black carbon is a major component of PM2.5 and a potent warming agent in the atmosphere, and contributes to regional environmental disruption and accelerates glacier melting.
- Hydrofluorocarbons (HFCs) are greenhouse gases (GHGs) commonly used in refrigeration, air-conditioning (AC), building insulation, fire extinguishing systems, and aerosols.
- Tropospheric ozone is formed by the interaction of sunlight, particularly ultraviolet light, with hydrocarbons and nitrogen oxides, which are emitted by automobile tailpipes and smokestacks.
- Nitrous oxide is a greenhouse gas which is 300 times more potent than carbon dioxide (CO2). A major proportion of the N2O emissions came from the agricultural sector.
- These gases are emitted from a broad range of sectors and sources, namely:
- Methane is mostly emitted from extraction, distribution and combustion of fossil fuel, industrial processes, enteric fermentation, rice cultivation, manure management, other agricultural sources, and the waste sector.
- N2O is mostly emitted from industrial processes, agricultural soils, manure management and wastewater.
- F-gases are mostly emitted from industrial processes.
- The share of non-CO2 pollutants contributing to global warming is almost as much as carbon dioxide.
- The Working Group III report of the Intergovernmental Panel for Climate Change (IPCC) deals with mitigating climate change, focuses on CO2 and a few greenhouse gasses, but excludes other non- CO2 pollutants.
- Warming from non- CO2 greenhouse gasses and black carbon soot was close to 80%.
- Without tackling non- CO2 pollutants, these gasses will continue to trap heat and keep the warming above 1.5°C, as there are not many cooling aerosols to mask the warming.
- Uncertainties around measuring non-CO2 pollutants such as methane and aerosols need to be addressed. The knowledge about their sources and mitigation methods needs to become mainstream.
- The study also raises other questions. Speaking of methane alone, there is also the political question of who reduces methane: Coal-consuming and rice-producing countries in the Global South, or oil and gas-consuming countries in the North. A global agreement for this is required.
SOURCE: THE HINDU,THE ECONOMIC TIMES,MINT