Contribution of Arctic seabird-colony ammonia to atmospheric particles and cloud-albedo radiative effect

NETCARE scientists and their collaborators are working to better understand connections between the components of the Arctic climate system. A study recently published in Nature Communications links ammonia emissions from summertime Arctic seabird-colony guano to observations of newly formed atmospheric aerosol particles. As shown in the below figure, these particles can in turn influence Arctic cloud properties, with resultant climate effects.

Atmospheric particles and clouds play a key, yet not well-understood role in modulating surface temperature, and thus understanding the factors that influence their characteristics is essential. Central to the development of clouds is the availability of cloud condensation nuclei – small atmospheric particles upon which water can condense. Using a combination of observations and computer modeling, NETCARE scientists have determined that summertime Arctic migratory-seabird colonies emit sufficient ammonia to influence atmospheric particles and clouds. Whilst concentrated around the seabird colonies, these seabird-influenced particles can grow and spread through the Arctic, encouraging cloud-droplet formation. As a consequence of cloud-characteristic changes, more incoming sunlight can be reflected back to space, a cooling effect, though not strong enough to offset the impacts of anthropogenic climate change that has led to considerable warming in the Arctic. There are details of the seabird-particle-cloud-climate interconnections that are not yet fully understood, including other possible aerosol-cloud interactions, which will require future study before the net effect of seabird-colony guano on the Arctic climate system can be determined. This newly identified and fascinating ecological-atmospheric connection highlights the interconnectedness of the many components of Earth’s climate system.


-Betty Croft, NETCARE HQP, Dalhousie

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