India is World’s Second Largest Emitter of Nitrous Oxide

India is the world’s second largest source of nitrous oxide (N2O), a greenhouse gas that heats up the atmosphere far more than carbon dioxide. Nearly 11% of such global man-made emissions in 2020 were from India, topped only by China at 16%. The major source of these emissions comes from fertiliser usage, according to a global assessment of N2O emissions published in the journal Earth System Science Data on June 12.

Data and Report

The report said that atmospheric concentrations of N₂O, the third most important greenhouse gas, are increasing faster than predicted by the Intergovernmental Panel on Climate Change (IPCC) emission scenarios. The concentration reached 336 parts per billion in 2022, a 25%  increase over pre-industrial levels that far outpaces IPCC predictions. While global carbon dioxide emissions from human activities (fossil fuel and land use change) have been rather stable over the past decade, global N₂O emissions continue to rise, largely due to production of food. The top five country emitters by volume of anthropogenic N2O emissions in 2020 were China (16.7%), India (10.9%), the United States (5.7%), Brazil (5.3%), and Russia (4.6%).

Nitrogen Fertilizers harmful for all

N2O emissions from human activities have increased by 40% (three million metric tons of N2O per year) in the past four decades, with growth rates between 2020 and 2022 higher than in any previous period since 1980, when reliable measurements began. Agricultural production using nitrogen fertilizers, such as ammonia, and animal manure contributed 74% of the total anthropogenic N2O emissions in the last decade. N2O emissions from human activities are responsible for 6.4% of the effective radiative forcing of greenhouse gases, and have added about 0.1°C to current global warming. The observed atmospheric N2O concentrations in the past decade have exceeded the most pessimistic, illustrative future greenhouse gas trajectories used by the IPCC that lead to global mean temperatures well above 3°C by the end of this century.

To know about IPCC

The IPCC is the Intergovernmental Panel on Climate Change and the arbiter of humanity’s scientific knowledge on the threat from global warming. “For net-zero emission pathways consistent with the Paris Agreement (stabilizing global temperatures below 2°C from pre-industrial levels), anthropogenic N2O emissions must decline by at least 20% relative to 2019 levels by 2050.”

Impact of Nitrous Oxide

Once emitted, N2O stays in the atmosphere for longer than the average human lifespan (117 years), and therefore its climate and ozone impacts are long-lived. In addition to N2O emissions, the inefficient use of synthetic nitrogen fertilizers and animal manure also leads to the pollution of groundwater, drinking water, and inland and coastal waters.

Reason behind emission

The increasing demand for meat and dairy products has exacerbated these emissions by boosting manure production. Similarly, the use of nitrogen fertilizers in animal feed production has further fueled this trend. While emissions from agriculture continue to rise, those from other sectors like fossil fuels and chemicals have stabilized or declined globally.