Can code save the planet?

The state of the world sometimes keeps me up at night. Global warming, plastics in the ocean, corruptions in the food supply, pharmaceuticals in the water supply, creeping fascism, political and financial turmoil...

What's a coder to do?

Surely technological visions and solutions also abound, and I'd like to know what they are. So tell me! I'm actually an optimist, despite the bleak view above.

I've been wondering - is it possible to apply the skill of coding to the act of saving the world? If so, how are you doing it? Do you know anybody else who is doing it? I want to know about projects, technologies and programmers who give you hope for the future!