Trees and plants also play an important role to help induce airflow and provide shade on hotter days in courtyards, and water is a common element because it can help cool the air through evaporation and can have a calming effect on the space.

WSJ: Full Enclosure - WSJ Mansion

Less ice on rivers, lakes and the sea will lead to more evaporation, probably increasing cloud cover at mid-levels, which should have a cooling effect.

ECONOMIST: The science