I recently came across a search engine Ecosia and I would like to recommend it to EAs. The company promises to use its a portion of its profit to fund re-forestation projects. Their website claims that they have planted 128 millions trees since its launch. People who have looked into it (here and here) found the company is legitimate.
From my experience, it works well for most searches, but sometimes you do need Google. Fortunately it's very convenient to specify search engine in firefox. I found this is a very easy way to do a bit good which cost nearly nothing.
The "Ecosia" link was broken, but I fixed it. You'll need to use https:// links in Markdown comments if you want them to work.