Last week, several prominent scientific organizations confirmed what had been predicted for months: 2024 was the hottest year on record. This sparked renewed calls for countries to rein in emissions of greenhouse gases, which superheat the planet and drive the climate crisis. Amid those pleas, experts urged nations not to forget about one often-overlooked gas: nitrous oxide. The compound warms the planet hundreds of times faster than carbon dioxide and, at the same time, destroys the stratospheric ozone layer, the barrier which protects the planet from harmful solar radiation. “Nitrous oxide is not as well known by the public as some other greenhouse gases, but it can be a remarkably destructive substance,” says Martina Otto, Head of Secretariat of the Climate and Clean Air Coalition, which is convened by the United Nations Environment Programme (UNEP). “The good news is that with strong policymaking and international cooperation, it is possible to slow emissions of this super pollutant – and save millions of lives around the world.” Here is everything you need to know about the hidden perils of nitrous oxide and how humanity can curb its impact on the planet. What is nitrous oxide? Nitrous oxide is a molecule comprised of two nitrogen atoms and one oxygen atom. While it has long been used in medical settings as an anaesthetic colloquially known as laughing gas, at elevated levels, it’s a super-pollutant. Nitrous oxide traps heat in the atmosphere, contributing to climate change. It also breaks down the molecules that form the stratospheric ozone layer, which shields Earth from damaging ultraviolet radiation from the sun. What are the main sources of nitrous oxide? Nitrous oxide is part of the nitrogen cycle. It occurs naturally in soil and water when bacteria break down nitrogen through processes called nitrification and denitrification. It is also common byproduct of agriculture. When too much nitrogen-based fertilizer is used on crops, nitrogen can leach out of the soil and into the broader environment, forming nitrous oxide. Some 75 per cent of human-made nitrous oxide emissions since 1980 have come from the farming sector. Industrial sources account for 5 per cent of human-caused releases, while the remaining 20 per cent comes from fossil fuel combustion, wastewater treatment and other sources. Are nitrous oxide emissions rising? Yes, and much faster that had been thought, found a report released last year by UNEP and the Food and Agriculture Organization (FAO) of the United Nations. More than 28 million tonnes of nitrous oxide were emitted in 2020, compared to 17 million tonnes in an average year before the industrial revolution. A key driver of this spike is the increased use of synthetic fertilizers to feed the world’s surging population, the report says. The concentration of nitrous oxide in the atmosphere has skyrocketed during the last 70 years. Credit: UNEPWhere does nitrous oxide rank in the pantheon
Sab. Gen 18th, 2025
