Paris: The production and use of nitrogen fertilizers account for 5 percent of global greenhouse gas emissions, which could be largely reduced by some available interventions, a new study said on Thursday.
Nitrogen fertilizers – produced and used around the world – are vital to global food security.
But their harmful emissions contribute to global warming more than the aviation sector, and on a par with the iron and steel, cement and plastics industries.
Most existing research has focused on emissions associated with the production of fertilizers, but Thursday̵7;s study showed that the majority — two-thirds — come from the use of fertilizers in agricultural land.
“There’s a perception that the petrochemical industry producing fertilizers is causing the emissions, but in fact it doesn’t seem to be the case. It was very surprising to us,” co-author Andre Cabrera Cerenho from the University of Cambridge told AFP.
The findings are important because they show “we must prioritize action to reduce emissions,” he said.
The study, published in the journal Nature Food, says carbon emissions could be reduced by up to 80 percent by 2050 while still producing enough food to feed a growing global population.
“The interventions proposed in our study do not mean a reduction in crop productivity, and they take into account the growing demand for food to feed a growing global population in the future,” confirmed Serenho.
“We are really inefficient in the way we currently use fertilizers,” he said. “We put a lot more fertilizer on crops than the amount of nitrogen that is actually needed to grow crops.”
The main emissions in the use phase are from the degradation of fertilizers by bacteria that are present in the soil and produce nitrous oxide, one of the most potent greenhouse gases.
Carbon dioxide and methane are also emitted in the use phase, but simply using less fertilizer can help reduce those harmful emissions.
But persuading farmers to use fertilizers more efficiently – for example, applying small amounts daily rather than spraying them once a season in large quantities – will require policy changes.
“If we can give farmers more economic incentives to change practices to reduce emissions, that’s the most obvious place to start,” Cerenho said.