PORTLAND, Maine (AP) — NASA astronaut Chris Cassidy is keeping his exploration impulses down-to-earth, biking 600 miles across the Amazon to raise awareness about climate change and record its effects.

Cassidy tells WCSH-TV (http://on.wcsh6.com/2wo0WDt ) in Maine, where he grew up, that the world is affected by every action humans take. He is traversing the South American jungle with a team of environmental scientists as part of a documentary.

The Amazon is vital to understanding climate change on a global scale. Scientists say as deforestation destroys more of the massive jungle, there's less...