Rising nitrous oxide emissions could put Paris Agreement goals out of reach

Oct. 7 (UPI) — Around the world, nitrous oxide emissions are rising, imperiling the effort to meet the climate goals set by the Paris Agreement.

According to a new study, published Wednesday in the journal Nature, the growing use of nitrogen fertilizers by industrial agriculture has led to a dramatic increase in N2O emissions.

For the study, researchers analyzed major N2O sources and sinks all over the world. The effort was aided by scientists from 48 research institutions in 14 countries.

“This study presents the most comprehensive and detailed picture to date, of N2O emissions and their impact on climate,” lead study author Parvadha Suntharalingam, climate scientist at the University of East Anglia in Britain, said in a news release.

The data showed modern atmospheric nitrous oxide levels are 20 percent higher than preindustrial levels, increasing to 331 parts per billion in 2018 from 270 parts per billion in 1750. The majority of the increase, scientists determined, occurred during the last half-century — and is the result of human activities.

“The dominant driver of the increase in atmospheric nitrous oxide comes from agriculture, and the growing demand for food and feed for animals will further increase global nitrous oxide emissions,” said study co-author Hanqin Tian.

“There is a conflict between the way we are feeding people and stabilizing the climate,” said Tian, director of the International Center for Climate and Global Change Research at Auburn University.

The findings underscore the message from the United Nations that the effort to curb climate change demands significant land-use changes, researchers say.

Like carbon dioxide and methane, nitrous dioxide is a greenhouse gas, but its warming effect is 300 times more potent than CO2. Once emitted, scientists estimate N2O remains in the atmosphere for more than a century.

The new analysis showed agricultural practices are the primary driver of N2O emissions. Over the last 40 years, nitrogen additions to croplands have increased 30 percent. According to the study, N2O emissions have risen fastest in East Asia, South Asia, Africa and South America.

Scientists found that Europe is one of the only places where N2O usage is declining, thanks to the adoption of more sustainable fertilizer use across the agricultural sector. Researchers said they hope similar efforts will be adopted — and swiftly — in other parts of the world.

“This new analysis calls for a full-scale rethink in the ways we use and abuse nitrogen fertilizers globally and urges us to adopt more sustainable practices in the way we produce food, including the reduction of food waste,” said researcher Josep Canadell, executive director of the Global Carbon Project. “These findings underscore the urgency and opportunities to mitigate nitrous oxide emissions worldwide to avoid the worst of climate impacts.”

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