Artificial nitrogen-based fertilizers used worldwide are significantly more harmful to the climate than previously assumed. This is the conclusion of a study by Cambridge University. Accordingly, the use of nitrogen fertilizers is responsible for more greenhouse gases than car and ship traffic combined.
Even if it has been known for a long time that fertilizer is harmful to the climate, it is still used extensively - worldwide. As reported by "Der Standard", around 117.5 million tons of nitrogen fertilizer were produced in 2018. This makes it one of the most important sources of income for the petrochemical industry. Almost half of the world's population eats food produced using nitrogen fertilizers.
And that is increasingly becoming a problem. For several reasons: On the one hand, the entire industry has come under massive pressure due to the increased gas prices caused by the Ukraine war. An important component of fertilizer production is ammonia, which is obtained from natural gas.
On the other hand, it is gradually becoming clear to what extent fertilizer is affecting the global climate. The Cambridge University research team found that the use of nitrogen fertilizers causes greenhouse gas emissions in the order of 2.6 billion tonnes a year - more than the world's air and shipping combined.
But not only the production of the fertilizer is a problem. "It's incredible that we don't know how many chemicals we produce worldwide, where they end up, where and how they accumulate, how many emissions they cause and how much waste they produce generate," says André Cabrera Serrenho, one of the authors of the study. Production is only responsible for about a third of emissions. The other shares were accounted for by the "application", i.e. the use of the fertilizer.
The researchers came to this conclusion because they were able to break down the entire life cycle of the fertilizer. "It was surprising that this was the largest source of emissions," Serrenho said. The results now provide information on which measures can be taken to limit the negative effects.
According to the researchers, many possibilities are already known. A step could already be taken by decarbonizing the ammonia in production. In addition, chemicals could be added to counteract climate-damaging nitrous oxide, which is a by-product of production. The scientists emphasize that these measures would make production more expensive and therefore propose compensation payments for the companies.
According to the researchers, an even greater effect can be achieved in a very practical way: "We are incredibly inefficient when it comes to using fertilizers," explained Serrenho. "We consume a lot more than necessary." This is not only harmful to the climate, but also uneconomical.
According to a study from 2015, only 42 percent of the fertilizer used actually reaches the plants. More than half will be scattered unnecessarily. According to the Cambridge researchers, it is possible to increase efficiency to 67 percent. In addition, the high-emission urea from ammonium nitrate could be replaced.
According to the researchers, it is fundamentally possible to reduce greenhouse gases by up to 80 percent without losing productivity. "We need to find the right mix of financial, technological and political solutions to reduce emissions while feeding the world," Serrenho said.
Sources: The Standard, University of Cambridge study