Non CO2 Pollutants | 31 May 2022

Why in News?

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.

What are Non-CO₂ Pollutants?

• About: The Non-CO₂ Pollutants include methane, black carbon, hydrofluorocarbons (HFC), tropospheric ozone and nitrous oxide.
  • Methane: Methane is a potent greenhouse gas. It contributes to the formation of ozone.
  • Black Carbon: 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 (HFC): 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: 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.
• Sources: 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.
• Contribution in Global Warming: The share of non-CO2 pollutants contributing to global warming is almost as much as carbon dioxide.
  • IPCC WGI reports have shown that the contribution of CO₂ and non-CO₂ greenhouse gases to global heating was 52-57% and 43-48 %, respectively.

What is the Issue?

• 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.

What are the Recent Initiatives to Tackle Non-CO₂ pollutants?

• The Glasgow Climate Pact, an agreement signed during the 2021 United Nations Climate Change Conference (CoP26), recognised the need to consider further actions to reduce non-carbon dioxide greenhouse gas emissions, including methane, by 2030.
  • Global Methane Pledge: The US and the European Union launched the Global Methane Pledge at the COP26 in Glasgow. More than 100 countries have committed to cut methane emissions by 30% by 2030.
    • India has not signed up for the Global Methane Pledge
• Indian Council of Agricultural Research (ICAR) has developed an anti-methanogenic feed supplement ‘Harit Dhara’ (HD), which can cut down cattle methane emissions by 17-20%.

Way Forward

• 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: DTE