He told the COP26 climate conference in Glasgow that he had grasped nature’s fragility when he travelled into space.
Entrepreneurs including Mr Bezos have been criticised for spending money on trips into space instead of solving problems on Earth.
Amazon has also been criticised by its workers over environmental practices.
Speaking to the COP26 conference, Mr Bezos said: “In too many parts of the world, nature is already flipping from a carbon sink to a carbon source.”
The Bezos Earth Fund plans to spend $10bn fighting climate change overall.
In Glasgow the founder of the world’s biggest online retailer described the experience of travelling on his rocket ship, New Shepard, in July as a revelation of Earth’s vulnerability.
“I was told that seeing the Earth from space changes the lens from which you view the world but I was not prepared for just how much that would be true,” he said.