Researchers calculate the lifecycle carbon footprint of fertilizers, which account for about 5% of total greenhouse gas emissions, for the first time accurately quantified, reducing carbon emissions to one-fifth of today’s levels I discovered that it can be done. level by 2050.
Our work gives us a good idea of what is technically possible and where intervention could be meaningful.To make rapid and meaningful progress in reducing emissions, it is critical to direct interventions where they matter most
Andre Cabrera Sereno
Researchers at the University of Cambridge found that two-thirds of emissions from fertilizers occur after they are applied to the fields, and one-third of the emissions come from the production process.
Nitrogen-based fertilizers are already known to be a major contributor to greenhouse gas emissions, but this is the first time their overall contribution from production to deployment has been fully quantified. Their analysis found that manure and synthetic fertilizers emit the equivalent of 2.6 gigatonnes of carbon per year.
There is an urgent need to reduce carbon emissions from fertilizers. However, this must be balanced with the need for global food security. Previous studies estimated that 48% of the world population eats crops grown with synthetic fertilizers, and that the world population will grow by 20% by 2050.
Cambridge researchers say a combination of scalable technical and policy solutions is needed to reduce fertilizer emissions while maintaining food security. However, they estimate that if such a solution could be implemented at scale, emissions from manure and synthetic fertilizers could be reduced by as much as 80% to one-fifth of current levels without compromising productivity. increase. The results are reported in Nature Food.
“It is incredible how much chemicals we produce in the world, where they end up, where and how they accumulate, how much emissions we produce, how much waste we produce. I don’t really know the Engineering Faculty of Cambridge.
Serrenho and co-author Yunhu Gao embarked on a project to accurately measure the total impact of fertilizers, one of the two major products of the petrochemical industry. Of all the products produced by the petrochemical industry, the majority (as much as 74%) are plastics or fertilizers.
“To reduce emissions, it is important to identify and prioritize interventions that can be done to reduce the environmental harm of fertilizers,” said Serrenho. “But to do that, we first need to have a clear picture of the entire lifecycle of these products. It sounds obvious, but in reality we know very little about these things.”
By adjusting for production and consumption of nitrogen fertilizers and regional emission factors across nine regions of the world, the researchers calculated the 2019 global growth rate for fertilizers and synthetic fertilizers along all life cycle stages. We mapped the streams and their emissions.
After completing their analysis, researchers found that unlike many other products, the majority of fertilizer emissions occur during use, not during production.
“It was surprising that this was a major source of emissions,” said Serrenho. “But only when we quantify all emissions at every point in the lifecycle can we begin to consider different mitigation methods to reduce emissions without compromising productivity.”
Researchers have listed and quantified the maximum theoretical impact of various mitigation methods. Most of these are already known, but the maximum potential effect has not been quantified.
Emissions from synthetic fertilizer production are mainly due to the synthesis of ammonia, partly due to chemical reactions used in the production process. At the manufacturing stage, the most effective mitigation would be for the industry to decarbonize heating and hydrogen production. Additionally, fertilizers can be mixed with chemicals called nitrification inhibitors that prevent bacteria from forming nitrous oxide. However, these chemicals can make fertilizers more expensive.
“If we are going to make fertilizer more expensive, we need some kind of financial incentives for farmers and fertilizer companies,” said Serrenho. “Agriculture is an incredibly tough business in its current state, and farmers are currently not being rewarded for cutting emissions.”
However, the most effective way to reduce fertilizer-related emissions is to use less fertilizer. “Using fertilizer is incredibly inefficient,” he says Serrenho. “We use more than we need. This is economically inefficient and depends on agricultural practices. If we use fertilizer more efficiently, we need much less fertilizer. , we can reduce emissions without affecting crop productivity.”
Researchers also looked at the mix of fertilizers used around the world, which varies by region. The researchers say that replacing some of the highest-emission fertilizers, such as urea, with ammonium nitrate around the world could reduce emissions by another 20% to 30%. However, this is only beneficial after decarbonizing the fertilizer industry.
“There is no perfect solution,” says Serrenho. “We need to rethink how food is produced and what economic incentives are most effective. Perhaps that means farmers pay to produce less emissions, perhaps it means more It means paying for food, and we need to find the right mix of finance, technology and policy to keep feeding the world and reducing emissions.”
Serrenho and Gao estimate that emissions from the fertilizer sector could be reduced by up to 80% by 2050 by implementing all the mitigation measures analyzed.
“Our work gives us a good idea of what is technically possible, what is big and where intervention makes sense. , it is important to direct interventions to what is most important,” said Serrenho. .
The study is part of the C-THRU project led by Professor Jonathan Cullen, in which researchers from four UK and US universities are working to clarify emissions from global petrochemical supply chains. increase.
Original: Carbon emissions from fertilizer could be reduced by up to 80% by 2050
Than: Cambridge University
