Noctilucent clouds, Earth's highest clouds, shine blue in the twilight sky from late May to August in the northern hemisphere ...

New study finds that ammonia aerosols from penguin guano likely play an important part in the formation of heat-shielding ...

Previous models have found clouds fueled by seabird guano in the Arctic do cool the ground, but the study authors say ...

Huge colonies of penguins in Antarctica fill the air with ammonia, which stabilises particles in the atmosphere that allow ...