Science magazine calls for reduced use of nitrogen fertilizers.Ottawa—Farm use of fertilizers to boost crop production is once again getting the wrap for worsening the planet's greenhouse gas problems without recognizing that the 4-R Program developed by Fertilizer Canada presents a solution.An article in ZME Science, an online publication that generally places science well ahead of sensationalism, says Earth is on track for a dangerous 3℃elsius warming this century and a lot of blame lies with more than 100 million tonnes of nitrogen “spread on crops in the form of synthetic fertilizer. The same amount again is put onto pastures and crops in manure from livestock.”This practice creates nitrous oxide (N₂O), a greenhouse gas. While it is normally destroyed in the upper atmosphere by solar radiation, “humans are emitting N₂O faster than it's being destroyed, so it's accumulating in the atmosphere. N₂O both depletes the ozone layer and contributes to global warming,” the article says.“Agriculture is the main cause of the increasing concentrations, and is likely to remain so this century. N₂O emissions from agriculture and industry can be reduced, and we must take urgent action if we hope to stabilise Earth's climate.”Fertilizer Canada says “fertilizer is essential for crop production but needs to be used sustainably to ensure nutrients aren't lost to the environment. Nitrous oxide is a potent greenhouse gas, but our 4R Nutrient Stewardship framework is science-based and has been proven to reduce emissions by at least 25 percent.“Our industry stands ready to work with all governments to ensure the promotion and inclusion of 4R Climate-Smart within any offset system to encourage growers to implement practices that will sustainably intensify crop production and reduce nutrient loss.”4R stands for the Right Source @ the Right Rate, Right Time and Right Place and is the centrepiece of the Nutrient Stewardship initiatives launched by Fertilizer Canada a decade ago.The article says agriculture caused almost 70 per cent of global N₂O emissions in the decade to 2016. “Reducing fertilizer use on farms is critical to reducing N20 emissions…As a greenhouse gas, N₂O has 300 times the warming potential of carbon dioxide and stays in the atmosphere for an average 116 years. It's the third most important greenhouse gas after CO₂, which lasts up to thousands of years in the atmosphere, and methane.N₂O depletes the ozone layer when it interacts with ozone gas in the stratosphere. Emissions from agriculture mostly came from synthetic nitrogen fertilizer used in East Asia, Europe, South Asia and North America, the article says. Emissions from Africa and South America are dominated by emissions from livestock manure.In terms of emissions growth, the highest contributions come from emerging economies such as Brazil, China, and India where crop production and livestock numbers have increased rapidly in recent decades.Alex Binkley is a freelance journalist and writes for domestic and international publications about agriculture, food and transportation issues. He's also the author of two science fiction novels with more in the works.