Plant a tree.

42,000,000 trees are cut down each year. (quora.com) Many of these are to make room for animal agriculture. So, any tree that we can replace is good for Mother Earth.

Make sure to check your soil to see what will grow well. I have planted a plum tree, some small pine trees, and two Japanese Maples. The plum tree and one of the pines seem to be stagnant- not growing any more. But they are still alive, so I have not done anything about them. Hopefully, they will come around.

If you are lucky enough to have good soil, consider planting a fruit tree. It is a bonus that you get food out of it!