It all works just like any other search engine, but Ecosia donates surplus advertising income to a tree planting program. When you search the web with Ecosia, 80% of the profits from the search ad revenue goes to support tree planting programs.

"By planting a tree, you can fight climate change, restart water cycles, turn deserts back into fertile forests and provide nutrition, employment, education, medical assistance and political as well as economic stability. Mind-boggling, isn't it?," Ecosia team explained about their decision to plant tree.

Till now they have plant 6.433.560 trees and you can see number raising any second. Read more about the project here.