New research suggests that ammonia compounds in guano at large penguin colonies could be a significant factor in the formation of low-altitude ocean clouds that help cool the planet.Bob Berwyn/Inside Climate News

This story was originally published by Inside Climate News and is reproduced here as part of the Climate Desk collaboration.

New research shows that penguin guano in Antarctica is an important source of ammonia aerosol particles that help drive the formation and persistence of low clouds, which cool the climate by reflecting some incoming sunlight back to space.

The findings reinforce the growing awareness that Earth’s intricate web of life plays a significant role in shaping the planetary climate. Even at the small levels measured, the ammonia particles from the guano interact with sulfur-based aerosols from ocean algae to start a chemical chain reaction that forms billions of tiny particles that serve as nuclei for water vapor droplets.

The low marine clouds that often cover big tracts of the Southern Ocean around Antarctica are a wild card in the climate system because scientists don’t fully understand how they will react to human-caused heating of the atmosphere and oceans. One recent study suggested that the big increase in the annual global temperature during 2023 and 2024 that has continued into this year was caused in part by a reduction of that cloud cover.

“I’m constantly surprised at the depth of how one small change affects everything else. This really does show that there is a deep connection between ecosystem processes and the climate.”

“I’m constantly surprised at the depth of how one small change affects everything else,” said Matthew Boyer, a coauthor of the new study and an atmospheric scientist at the University of Helsinki’s Institute for Atmospheric and Earth System Research. “This really does show that there is a deep connection between ecosystem processes and the climate. And really, it’s the synergy between what’s coming from the oceans, from the sulfur-producing species, and then the ammonia coming from the penguins.”

Aquatic penguins evolved from flying birds about 60 million years ago, shortly after the age of dinosaurs, and have persisted through multiple, slow,........

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