jmac, I found myself catalyzed yesterday into becoming a $20 / month donor to Earth Justice (https://earthjustice.org), an environmental-law organization that combats threats to our biosphere by throwing lawyers at them. This appeals to me.
I am a well-off tech worker who cares about climate but is unlikely to actually go plant a tree or whatever, so donating generously to charitable causes is the best way that I can help. If you're in similar straits, consider joining me?