This satellite image of the skies over the southeastern United States shows contrails—plumes of ice crystals formed in jet exhaust—of vacation flights to and from Florida. Scientists think that the clouds contrails form are increasing the greenhouse effect and contributing to global warming. NASA scientist Patrick Minnis' research suggests that jet trails may have warmed the air over the United States by as much as one-half degree Fahrenheit each decade since 1975.

Next piece of evidence:
Corals

Photo courtesy Louis Nguyen and Patrick Minnis, NASA