• India emerged as the world’s second largest source of nitrous oxide (N2O), according to a report published in Earth System Science Data.

• Nitrous oxide emissions grew by 40 per cent between 1980 and 2020, with China being the largest emitter.

• The study said that 74 per cent of the nitrous oxide emissions in the past decade came from the use of nitrogen fertilizers and animal manure in agriculture.

• The top 10 emitters are China, India, the United States, Brazil, Russia, Pakistan, Australia, Indonesia, Turkey, and Canada.

Nitrous Oxide

• Nitrous oxide (N2O) is an important climate-relevant trace gas in the Earth’s atmosphere. In the troposphere it acts as a strong greenhouse gas and in the stratosphere it acts as an ozone depleting substance because it is the precursor of ozone depleting nitric oxide radicals. 

• Nitrous oxide is the third most significant greenhouse gas after carbon dioxide and methane and is 273 times more potent than CO2 over 100 years.

• N2O contributes to climate change due to its positive radiative forcing effect.

• N2O accounts for about 7 per cent of the radiative forcing by long-lived greenhouse gases.

• N2O is emitted into the atmosphere from both natural sources (approximately 60 per cent) and anthropogenic sources (approximately 40 per cent), including oceans, soils, biomass burning, fertilizer use, and various industrial processes. Other important sources include road transport, other fuel combustion sources and waste processes. 

• Nitrous oxide can result from various agricultural soil management activities, such as application of synthetic and organic fertilizers and other cropping practices, the management of manure, or burning of agricultural residues. 

• Nitrous oxide is emitted when fuels are burned. The amount of N2O emitted from burning fuels depends on the type of fuel and combustion technology, maintenance, and operating practices.

• N2O emissions occur naturally through many sources associated with the nitrogen cycle, which is the natural circulation of nitrogen among the atmosphere, plants, animals, and microorganisms that live in soil and water. Nitrogen takes on a variety of chemical forms throughout the nitrogen cycle, including N2O.

• Historically, industrial processes have been a significant source, due to emissions from the manufacture of chemicals — nitric acid and adipic acid.

• Nitrous oxide molecules stay in the atmosphere for an average of 121 years before being removed by a sink or destroyed through chemical reactions.

India’s initiatives to reduce nitrous oxide emissions

• The government of India is implementing several programmes to reduce nitrous oxide emissions in the country. 

• Neem Coated Urea scheme is one of the key programmes.

• As urea fertilizer is a major source of nitrous oxide, the government has introduced 100 per cent neem-coated urea in the country to reduce the emissions of nitrous oxide and increase the nitrogen use efficiency.

• Further, another programme of the government is the National Innovations in Climate Resilient Agriculture (NICRA). It aims at developing resilient technologies that reduce nitrous oxide emissions from the agriculture sector.

• Some of these technologies/practices include soil test-based nitrogen application, zero tillage, crop residue management, use of organic manure, crop rotation with legumes and use of nitrification inhibitor coated urea fertilizer like neem-coated urea.

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