Extreme heat could make photosynthesis impossible for tropical trees and plants that may all die as a result, a new study found.

• Trees stop making food for themselves when they get too hot, a new study shows.
• If tropical air temperatures reach 116 degrees Fahrenheit, a lot of the rainforest could die. 
• This is the first study to narrow in on a threshold that we need to avoid. 

When trees get hot, their leaves begin to sweat. If they stay hot for too long, they deplete their water supply, exhausting themselves.

It's then that photosynthesis, the backbone of plant life, breaks down. 

The plant stops being able to care for itself, and begins to die, scientist Gregory Goldsmith, an assistant professor of biology at Chapman University, said in a press briefing.