How Nitrous Oxide is fuelling climate change

It’s time to deal with N2O swiftly before humanity becomes a laughing stock

“The human race has only one really effective weapon and that is laughter,” said Mark Twain. However, it’s time to ensure that the armament is not mistaken for nitrous oxide (N2O), nicknamed ‘laughing gas’, for making a person a bit giggly.

An odourless, colourless, non-flammable gas, N2O is often used as an anesthetic for dental procedures.

It is also a greenhouse gas (GHG), having a warming potential in the atmosphere 300 times greater than carbon dioxide (CO2) and can linger for over 100 years. It contributes to six per cent of human-driven climate change, pollutes the soil, water, and air, and depletes the ozone layer.

Scientists claim that while 60 per cent of global N2O emissions occur naturally, 40 per cent are attributed to human activities.

Even as global climate policies included curbing other GHGs, N2O has gone unchecked and climbed sorely. It captures reradiated infrared radiation from the Earth’s surface and warms the troposphere (lower atmosphere).

Since the beginning of industrialisation, the atmospheric concentration of N2O has increased by 23 per cent, and emissions continue to surge rapidly.

This rise poses a dual threat: exacerbating global warming and depleting the ozone layer. If it continues, the ozone layer could become significantly thinner, leading to higher levels of harmful ultraviolet (UV) radiation reaching the Earth’s surface and increasing the risk of cancer and threatening crops and aquatic life.

Causes and effects

For decades, the concentration of N2O in the atmosphere has increased due to the use of synthetic nitrogen fertiliser in agricultural soil globally.

The 2020 statistics revealed that 123 metric tons of nitrogen was produced as artificial fertiliser, a nearly tenfold increase in 60 years. This stimulates plant growth and generates more N2O, a chief source of man-made misadventures.

Since the 1980s, worldwide emissions in the sector have increased by over 45 per cent.

Researchers say that the levels of the gas in the atmosphere belied earlier predictions of the United Nation’s Intergovernmental Panel on Climate Change (IPCC) and rose to 336 parts per billion (ppb) in 2022, a 25 per cent increase over pre-industrialised levels. Over the past 20 years, it has increased about 1.3 ppb annually.

However, N2O does not only occur in areas where fertiliser is used. Reactive nitrogen travels from the soil into the ground and surface water.

Aside from affecting the water quality, nitrogen leads to the formation of N2O, as it travels to other ecosystems through the air and ends up on the ground or in oceans, which is why N2O emissions from the oceans have increased.

Though primarily attributed to agricultural practices, accounting for about 74 per cent of global N2O emissions, it is also used to manage livestock manure.

Other than that, transportation, stationary combustion sources (mainly coal plants), industrial activities, including the production of nitric acid, and using N2O in chemical manufacturing, contribute to its emissions.

Also, hydrogen production, particularly through processes like steam methane reforming, can result in N2O outpouring.

India, China, the United States, Brazil, Russia, Pakistan, Australia, and Canada are the top N2O emitters, because of their rapidly growing populations and increased demands in the food sector.

The way out

Addressing this issue requires concerted efforts to reduce emissions from agriculture, industry, and energy production. Implementing sustainable agricultural practices, improving waste management, and developing cleaner industrial processes are crucial steps toward mitigating the environmental impact of this potent gas.

Researchers suggest that the compound (produced by the breakdown of nitrogen in fertilisers and sewage treatment plants) should be reduced to avoid thinning the protective ozone layer that blankets the Earth.

Soil management techniques can help decrease the outflow. For example, remote sensing technology can help implement precision agriculture to sense when nitrogen should be applied to fields. Similarly, irrigation methods, including drip and subsurface drip decrease N2O emissions.

Several regenerative agriculture practices can also handle this issue. Curtailing pesticides encourages a diverse microbial community, which leads to natural fixation. This converts atmospheric nitrogen, limiting the need for artificial nitrogen fertilisers.

Governments must educate farmers to reduce emissions using nitrogen fertilisers, genetically modified crops, animal waste management, and sustainable farming practices.

Also, nitrogen-fixing cover crops, including clover can reduce the amount of synthetic nitrogen fertiliser.

Wastewater treatment also creates N2O as a by-product of activated sludge processes to speed up waste decomposition. Low concentrations of ammonia and nitrite in effluent can decrease the emissions. Developing cleaner energy sources for electricity will also be beneficial.

Setting benchmarks

Reports indicate that once the world’s top N2O emitter, Europe has managed a decrease by reducing the use of fossil fuels. Its emissions related to agriculture are declining. Likewise, emissions in Japan and South Korea have also dropped.

However, if global warming is to remain below 2°C, as per the climate targets of the Paris Agreement, anthropogenic N2O emissions must decline by 20 per cent by 2050.

It’s time to deal with N2O swiftly before humanity becomes a laughingstock.

(Next Thursday the author will discuss 'smart cities') 

Dr Abdullah Belhaif Al Nuaimi is Chairman of the Advisory Council of the Emirate of Sharjah