Surge in N20: Are Fertilizers to be Blamed?

China is the largest source of nitrous oxide (N20) in the entire world. Which country is the second largest source? Unfortunately, India.

Nitrous oxide is a greenhouse gas. It is responsible for heating up the atmosphere. Carbon dioxide is another such gas, but the heating caused by carbon dioxide is far less than that of nitrous oxide. As per an assessment published in the Earth System Science, about 11 percent of this global man-made emissions in the year 2020 were actually coming from India. China, on the other hand, is the source of nearly 16 percent.

Fertilizers stand as a major contributor to this rise, as per the global assessment of the nitrous oxide emissions.

In the year 2022, the concentration of N20 in the atmosphere touched 336 parts per billion. This is over 25 percent more than the levels recorded prior to the industrial age. The carbon dioxide concentration has been recorded to be 417 parts per million in the year 2022.

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Does this mean that the level of carbon dioxide is more than nitrous oxide? Well, yes, it is thousand times more than the levels of nitrous oxide. However, here is an interesting point to make. Nitrous oxide is a greenhouse gas that remains for a longer duration in the atmosphere. Moreover, the rise of nitrous oxide is really rapid. Scientists all over the globe have been warning about the increase of nitrous oxide and urge the world to view this concern with utmost urgency.

Fertilizers and nitrogen

In the last forty years, the emissions of N20 from human activities have surged by over 40 percent. Nitrogen fertilizers have increasingly been used in agricultural production. Along with agricultural production, it contributed to over 74 percent of the total anthropogenic nitrous  oxide emissions in the last decade. The nitrous  oxide emissions that are a result of human activities are actually responsible for about 6.4 percent of the effective radiative forcing. These emissions have added over 0.1°C to the current global warming.

The top five countries that emitted the highest N20 emissions by volume in the year 2020 were China, India, the United States, Brazil and Russia. Over 16.7 percent of the anthropogenic N20 emissions come from China while about 10.9 percent comes from India. Over 5.7 percent of the anthropogenic N20 emissions come from the United States while about 5.3 percent comes from Brazil. Russia is the source of about 4.6 percent of these emissions.

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