I saw that the Ecosia search engine is now available as a default setting on all Apple iPhones and iPads, so I did a little investigating. Basically they use the money that their search engine generates — revenues from ads — to plant trees and help the planet, and they’ve already planted a hundred million of them.
In short, I was really impressed. They do the right things with privacy, transparency, and the projects that they work on seem really impressive. The search results come from Microsoft’s Bing engine, which means that they are not that much worse than Google, and I have found it really easy to switch.