Unexpected: human nitrogen emissions cool the climate

Nitrogen, an omnipresent element in the atmosphere, reveals an unexpected side: its emissions have a cooling effect on the climate.


An international study conducted by the Max Planck Institute and the University of Sydney reveals that nitrogen emissions from fertilizers and fossil fuels have a cooling effect on the climate. However, this phenomenon is accompanied by numerous negative impacts on the environment and health, necessitating urgent action to reduce greenhouse gas emissions.

Researchers discovered that nitrogen emissions from human activities, such as the use of fertilizers and the combustion of fossil fuels, can cool the climate by blocking sunlight and promoting plant growth.

The findings, published in Nature, indicate that reactive nitrogen released by human activities cools the climate by 0.34 watts per square meter. Despite this cooling, greenhouse gases continue to rise, outweighing the beneficial effects of nitrogen-induced cooling.


Researchers warn that increasing nitrogen levels in the atmosphere is not a viable solution. Federico Maggi from the University of Sydney emphasizes that nitrogen fertilizers pollute water and nitrogen oxides from fossil fuels pollute the air, making this approach unacceptable for combating climate change.

Sönke Zaehle from the Max Planck Institute reminds us that nitrogen emissions have harmful effects on health, biodiversity, and the ozone layer. The findings should not overshadow the negative impacts of nitrogen or justify its increased use to combat global warming.

Elemental nitrogen, making up 78% of the air, is climate-neutral, but its reactive compounds can either warm or cool the climate. For example, nitrous oxide (N₂O) is a greenhouse gas almost 300 times more potent than CO₂.

The study highlights the importance of mathematical models in understanding the global impacts of nitrogen on the climate and environment.