NITROUS OXIDE (Syllabus GS Paper 3 – Sci and Tech)

Context: India emerged as the world's second largest contributor to nitrous oxide (N2O), a potent greenhouse gas, accounting for nearly 11% of global man-made emissions in 2020, primarily from fertilizer usage. China led with 16% of these emissions, according to a global assessment.

Key Findings of Study

• N2O Concentration: In 2022, atmospheric N2O reached 336 parts per billion, marking a 25% increase from pre-industrial levels.
• Emission Growth: Over the past four decades, human-induced N2O emissions have surged by 40%, equating to three million metric tons annually.

oBetween 2020 and 2022, emission growth rates were the highest observed since 1980, largely due to agricultural practices.

• Major Sources: Agricultural activities using nitrogen fertilizers and animal manure contributed 74% of total anthropogenic N2O emissions in the last decade.
• Climate Impact: These emissions account for 6.4% of the effective radiative forcing from greenhouse gases and have added approximately 0.1°C to global warming.
• IPCC Guidance: The IPCC stresses that to meet net-zero emission pathways aligned with the Paris Agreement goals, anthropogenic N2O emissions must decrease by at least 20% relative to 2019 levels by 2050.
• Leading Countries: In 2020, the top emitters were China (16.7%), India (10.9%), the United States (5.7%), Brazil (5.3%), and Russia (4.6%), underscoring the global distribution of N2O emissions.

Nitrous Oxide

• About: N2O is a greenhouse gas (GHG) that is 300 times more potent than carbon dioxide (CO2) in terms of its global warming potential.
• Atmospheric Concentration: It ranks third in concentration among GHGs in Earth’s atmosphere, following CO2 and methane (CH4), contributing significantly to global warming.
• Impact on Ozone Layer: N2O poses a threat to the ozone (O3) layer as it accumulates over time, similar to CO2, although it affects ozone differently than other pollutants.
• Longevity in the Atmosphere: It has a long atmospheric lifetime, remaining active for up to 125 years once emitted.
• Applications:
• Medical Use: N2O is used by dentists and medical professionals for sedating patients during minor medical procedures, owing to its anesthetic properties.
• Food Industry: It serves as a propellant in food aerosols, enabling the dispensing of whipped creams and other culinary foams.