"It is not your responsibility to finish the work of perfecting the world, but you are not free to desist from it either.” -- Rabbi Tarfon, Pirke Avot (Ethics of the Fathers)
Do something. Start with a place that’s comfortable for you, and then challenge yourself to do more over time. Don’t do nothing. Climate change can feel so big that it’s impossible for individuals to have any impact. But as the BBC reports, Erica Chenoweth, a political scientist at Harvard University, has studied non-violent protest movements and discovered that it takes only 3.5% of the population to change the world. More from the BBC: https://www.bbc.com/future/article/20190513-it-only-takes-35-of-people-to-change-the-world.
Climate scientist Katharine Hayhoe emphasizes the importance of talking to people: friends, family members, co-workers. Conversations about climate change and possible solutions are crucial to changing culture.
Join your local Environmental Commission, or another organization devoted to action and education around climate issues, and volunteer for local events and activities. If your town doesn’t have an Environmental Commission, start going to Town Council meetings and speaking up. If you have the organizational skills, start an environmental commission. If you don’t, persuade someone else to do it.
Call and write letters to local and state politicians. You’ll be able to make more of an impact at the local level than nationwide. A lot of important environmental initiatives, like plastic bag bans and improved bike lanes, start local.
If you have a retirement fund, disinvest from fossil fuels. Switch to a green portfolio.
The Rainforest Action Network publishes a list of banks that fund fossil fuels. If your bank is on the list, consider moving your savings and checking accounts to a different bank. Or start a petition to get your bank to divest from fossil fuels.
On a personal level, here's a list of actions individuals can undertake to reduce their own carbon footprint, as well as a catalogue of resources to help you stay educated as the climate scientists learn more and the engineers come up with better solutions.