Emissions of "Laughing Gas' Nitrous Oxide—A Potent Greenhouse Gas and Ozone Depleter—Are Increasing Far Faster Than IPCC Predictions

Emissions of nitrous oxide (N20) into the atmosphere have increased significantly over the past two decades, due in large part to agricultural practices, scientists have found.

This is not good news for the environment, given that N20 is a long-lived greenhouse gas 300 times more potent than carbon dioxide—which is helping to warm the planet by trapping heat radiating from the Earth's surface.

Furthermore, the gas is known to be one of the main depleters of the Earth's ozone layer—which protects us from harmful stellar radiation.

According to a study published in the journal Nature Climate Change, emissions of N20 have risen significantly between 1998 and 2016, with a particularly substantial increase after 2009.

In fact, between the periods 2000-2005 and 2010-2015, emissions increased globally by 1.6 teragrams every year. One teragram is equivalent to more than 2.2 million pounds.

This means that global N20 emissions have increased at a significantly faster rate over the last decade than estimates in the Intergovernmental Panel on Climate Change's guidelines.

The authors of the paper link this rise to agricultural practices that release nitrogen compounds into the environment—for example, the widespread use of nitrogen-rich fertilizers.

The cultivation of nitrogen-fixing plants—such as clover, soybeans alfalfa, lupins and peanuts—has also been a factor in the increase of N20 in the environment. These plants host bacteria in their roots that extract nitrogen from the air and convert it into a biologically useful form.

Furthermore, the burning of fossil fuels and biofuels have also played a key role in the rise of nitrous oxide emissions, albeit to a lesser extent than agricultural practices.

In terms of the world's regions, the study found that East Asia and South America provided the largest contributions to the global increase. The researchers say that understanding more about these emissions could help to combat the rise.

A farmer holds a soybean plant during the harvest at the Bardole & Son's Ltd farm on October 14, 2019 in Rippey, Iowa. Joe Raedle/Getty Images

"We already knew that atmospheric N2O levels were increasing, but our study was able to assign this increase to specific regions and emission sources, which is important for informing strategies to limit the growth of this greenhouse gas," Chris Wilson, one of the authors of the study from the School of Earth and Environment and National Centre for Earth Observation (NCEO) at Leeds University in the U.K., said in a statement.

In fact, mitigation strategies focusing on particular regions could be a useful way to reduce N20 emissions, according to study lead author Rona Thompson, from the Norwegian Institute for Air Research.

"Our results suggest that reducing nitrogen fertilizer use in regions where there is already a large nitrogen surplus, will result in larger than proportional reductions in N2O emissions," she said. "This is particularly relevant in regions such as East Asia, where nitrogen fertilizer could be used more efficiently, without reducing crop yields."

Furthermore, Martyn Chipperfield, another author of the study from the Institute for Climate and Atmospheric Science at Leeds, told Newsweek: "Based on this work we need to take care in using nitrogen fertilizers. We need to use the optimum amount region by region to ensure crop yield but avoid excess nitrogen."

Of the major greenhouse gases, nitrous oxide contributes around 20 percent of the total warming effect, in comparison to carbon dioxide (65 percent) and methane (16 percent), ABC News reported.

This article was updated to include comments from Martyn Chipperfield.