Carbon emissions from fertilizers could be reduced by as much as 80% by 2050

February 9, 2023. Science Daily. Researchers have calculated the carbon footprint for the full life cycle of fertilizers, which are responsible for approximately five percent of total greenhouse gas emissions — the first time this has been accurately quantified — and found that carbon emissions could be reduced to one-fifth of current levels by 2050.

The researchers, from the University of Cambridge, found that two thirds of emissions from fertilisers take place after they are spread on fields, with one third of emissions coming from production processes.

Although nitrogen-based fertilisers are already known to be a major source of greenhouse gas emissions, this is the first time that their overall contribution, from production to deployment, has been fully quantified. Their analysis found that manure and synthetic fertilisers emit the equivalent of 2.6 gigatonnes of carbon per year — more than global aviation and shipping combined.

Carbon emissions from fertilisers urgently need to be reduced; however, this must be balanced against the need for global food security. Earlier research has estimated that 48% of the global population are fed with crops grown with synthetic fertilisers, and the world’s population is expected to grow by 20% until 2050.

The Cambridge researchers say that a combination of scalable technological and policy solutions are needed to reduce fertiliser emissions while maintaining food security. However, they estimate that if such solutions could be implemented at scale, the emissions from manure and synthetic fertilisers could be reduced by as much as 80%, to one-fifth of current levels, without a loss of productivity. Their results are reported in the journal Nature Food.

“Incredibly, we don’t actually know how many chemicals we produce globally, where they end up, where and how they accumulate, how many emissions they produce, and how much waste they generate,” said co-author Dr André Cabrera Serrenho from Cambridge’s Department of Engineering.

Serrenho and his co-author Yunhu Gao undertook a project to accurately measure the total impacts of fertilisers, one of the two main products of the petrochemical industry. Of all the products made by the petrochemical industry, the vast majority — as much as 74% — are either plastics or fertilisers.

“In order to reduce emissions, it’s important for us to identify and prioritise any interventions we can make to make fertilisers less harmful to the environment,” said Serrenho. “But if we’re going to do that, we first need to have a clear picture of the whole lifecycle of these products. It sounds obvious, but we actually know very little about these things.” For more reading..