The increased use of fertilizers threatens the work of achieving climate goals - to keep global temperature rise below two degrees. It shows a new study published in the scientific journal Nature.
The study, which involved 57 researchers from 14 countries, is a survey of nitrous oxide emissions. Nitrous oxide is a greenhouse gas that is almost 300 times stronger than carbon dioxide and has a residence time in the atmosphere that is longer than 100 years. The results from the study show that nitrous oxide emissions are increasing and that the primary reason is the use of artificial fertilizers in agriculture.
Nitrous oxide emissions are increasing mainly in Asia, Africa, South America and in countries such as Brazil, China and India, emissions have increased the most, according to the study. Europe is the only region that has managed to reduce nitrous oxide emissions in the last 20 years. In Sweden, on the other hand, nitrous oxide emissions have increased by 24 percent over the past six years due to increased sales of fertilizers, according to the Swedish Environmental Protection Agency.
"If we do not reduce nitrous oxide emissions, the average temperature increase may well exceed three degrees above pre-industrial levels," said the study's co-author Parvadha Suntharalingam, a researcher at the University of East Anglia in England.
The goal of the Paris Agreement concluded about five years ago is that global warming should be limited well below two degrees and that efforts should be made to keep the temperature rise below 1,5 degrees.
The study has attracted the attention of several Swedish media, including Aktuell Hållbarhet and Dagens Industri where Ida Lind from Ekologiska Lantbrukarna commented on the results.
- Due to artificial fertilizers, we can pump a lot more nitrogen into the system than can be added naturally. This has led to such high nitrous oxide emissions, says Ida Lind.
In June released Ekologiska Lantbrukarnas report Agriculture and the climate which is a solid compilation of the research situation. The report indicates that we need to differentiate newly added and recycled nitrogen. The nitrogen that is added with the fertilizer is a new addition from the air, which has not previously been in circulation in agriculture. But when nitrogen is added via manure and plant residues, it is formed by the same nitrogen atoms that first entered agriculture via artificial fertilizer, biological nitrogen fixation or precipitation from the air. Based on this, the authors of the report state that "the impact of artificial fertilizers on nitrous oxide formation does not primarily depend on how much nitrous oxide is formed during the actual fertilization, but on how much new nitrogen it feeds into the system."
To reduce nitrous oxide emissions at global, national and regional levels, we need to promote nitrogen-efficient cultivation methods used on organic farms. We need to learn from organic farmers who grow in cycles between animals and plants and who provide nutrients to the soil in a sustainable way.
- A comprehensive quantification of global nitrous oxide sources and sinks. Nature. 2020.
- Agriculture and the climate - A holistic approach. Ekologiska Lantbrukarna 2020.
- Greenhouse gas emissions from agriculture. The Swedish Environmental Protection Agency.
- "Agricultural nitrous oxide emissions are overlooked". Today's industry.
- Nitrogen emissions from rising fertilizer use threaten climate goals. Reuters.