How Central Park cools the entire planet | Grist

But while evaporation from parks does cause clouds, they’re the other kind -- the kind that helps cool the Earth. The clouds that green spaces give rise to are low-lying and white, and they reflect sunlight back into space, acting like a sun shade on a hot day. And, according to Ken Caldeira, the principle investigator on this study, the clouds reflect 3/4 as much heat as they remove from the city. In other words, parks help the planet almost as much as they help the city.