Ammonia in the upper troposphere originates from livestock and fertiliser emissions, say the researchers. CERN says “anthropogenic ammonia has a major influence on atmospheric aerosol particles”. Implications for climate models are suggested.
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Aerosol particles can form and grow in Earth’s upper troposphere in an unexpected way, reports the CLOUD collaboration in a paper published today in Nature.
The new mechanism may represent a major source of cloud and ice seed particles in areas of the upper troposphere where ammonia is efficiently transported vertically, such as over the Asian monsoon regions.
Aerosol particles are known to generally cool the climate by reflecting sunlight back into space and by making clouds more reflective. However, how new aerosol particles form in the atmosphere remains relatively poorly known.