Context: India ranks as the second-largest emitter of nitrous oxide (N2O) globally, a greenhouse gas significantly more potent than carbon dioxide in terms of atmospheric heating.

Major sources of Nitous Oxide

• The major source of these emissions comes from fertilizer usage, according to a global assessment of N2O emissions published in the journal Earth System Science Data.

• Agricultural production using nitrogen fertilizers, such as ammonia, and animal manure contributed 74% of the total anthropogenic N2O emissions in the last decade.

Key points from the Study

• The study was published on global assessment of N2O emissions in the Journal Earth System Science Data.

• In 2020, India accounted for nearly 11% of global man-made N2O emissions, second only to China, which contributed 16%.

• Atmospheric N2O concentrations reached 336 parts per billion in 2022, about 25% higher than pre-industrial levels.In contrast, carbon dioxide levels were 417 parts per million, making carbon dioxide emissions a more immediate focus for climate change mitigation.

Primary source of emissions

• Human activities have driven a 40% increase in N2O emissions over the past four decades, with the rate of increase from 2020 to 2022 being the highest since measurements began in 1980. Agricultural activities, particularly the use of nitrogen fertilizers and animal manure, accounted for 74% of total anthropogenic N2O emissions in the last decade.

• While agricultural emissions continue to grow, emissions from other sectors like fossil fuels and the chemical industry are stable or declining globally.

• However, emissions from aquaculture, though currently only a tenth of those from land-based fertilizers, are growing rapidly.

Impact of emission

• N2O persists in the atmosphere for approximately 117 years, leading to long-term climate and ozone impacts.

• These emissions contribute to 6.4% of the effective radiative forcing of greenhouse gases, adding approximately 0.1°C to current global warming.

• According to the study, "The observed atmospheric N2O concentrations over the last ten years have surpassed the most pessimistic, illustrative future greenhouse gas trajectories used by the Intergovernmental Panel on Climate Change (IPCC), which lead to global mean temperatures well above 3°C by the end of this century”.

• In order to achieve net-zero emission paths that align with the Paris Agreement and stabilize global temperatures below 2°C from pre-industrial levels, there must be a minimum 20% decrease in anthropogenic N2O emissions by 2050 as compared to 2019 levels.

Environmental and Health Effects

• Environmental Pollution: N2O emissions can lead to pollution of soil, water bodies, and air, affecting ecosystems and human health.

• Health Risks: While N2O is relatively non-toxic at ambient levels, prolonged exposure or high concentrations can pose health risks, including respiratory issues and neurological effects.

Changing Food patterns

• The rising demand for meat and dairy products has increased manure production and subsequent N2O emissions. Moreover, nitrogen fertilizers used in animal feed production contribute to the rise in emissions.

Call for Action and Future Outlook

• Scientists warn that anthropogenic N2O emissions must decline by at least 20% relative to 2019 levels by 2050 to align with net-zero emission pathways consistent with the Paris Agreement.

• Nitrogen fertilizers, which are heavily subsidized in India, contribute significantly to N2O emissions. Urgent reforms are needed to promote alternative production systems and mitigate emissions.

Road Ahead

• Director of the Centre of Sustainable Agriculture, emphasized the urgency of addressing this issue, noting that India heavily subsidizes nitrogen fertilizers by over 80%.

• He called for a re-evaluation of fertilizer subsidies to support alternative production systems that would reduce both emissions and water pollution.

Intergovernmental Panel on Climate Change (IPCC)

• IPCC is the United Nations body for assessing the science related to climate change.

• It was created in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP).

• The objective of the IPCC is to provide governments at all levels with scientific information that they can use to develop climate policies.

• It currently has 195 members.

Paris Agreement

• It is a legally binding international treaty on climate change.

• It was adopted by 196 Parties at the UN Climate Change Conference (COP21) in Paris, France, on 12 December 2015. It entered into force on 4 November 2016.

• Its overarching goal is to hold “the increase in the global average temperature to well below 2°C above pre-industrial levels” and pursue efforts “to limit the temperature increase to 1.5°C above pre-industrial levels.”

• To limit global warming to 1.5°C, greenhouse gas emissions must peak before 2025 at the latest and decline 43% by 2030.