Nitrous Oxide Emissions from Agriculture: A Growing Threat to Our Climate

Nitrous oxide (N2O) is the third largest contributor to greenhouse gas emissions, posing a significant threat to our climate. While it may only account for 6% of total greenhouse gases, its global warming potential is 273 times higher than that of carbon dioxide (CO2). Once released into the atmosphere, N2O can persist for centuries, trapping heat and contributing to global warming. Furthermore, N2O in the stratosphere can undergo photochemical reactions that deplete the ozone layer, which protects us from harmful ultraviolet radiation.

Between 2007 and 2016, human activities released an estimated 7.3 teragrams of N2O annually, primarily due to agricultural practices. This has resulted in a steady increase in atmospheric N2O concentrations, reaching a record high of 331 parts per billion in 2018 – a 23% rise compared to pre-industrial levels.

Agricultural soils, particularly those treated with nitrogen-based fertilizers and organic manure, are the largest source of anthropogenic N2O emissions. These emissions are estimated to be between 3 and 4 teragrams per year and are increasing at a rate of 0.27 teragrams per decade. With the global annual nitrogen fertilizer input at approximately 113 million tonnes, it is estimated that for every 100 kilograms of nitrogen fertilizer applied to fields, roughly 1 kilogram is emitted as N2O.

Given the significant impact of agricultural N2O emissions on climate change, it is crucial to understand the factors influencing these emissions and develop effective mitigation strategies. This includes optimizing fertilizer application rates, using nitrification inhibitors to slow down the conversion of nitrogen fertilizers to N2O, and promoting sustainable farming practices such as crop rotation and no-till agriculture. Reducing N2O emissions from agriculture is not only essential for mitigating climate change but also for improving air quality and protecting human health.