On his website, there's a list of "10 thing you can do to save the Earth" (or rather humanity as the planet will be fine, whether we make it or not), which I replicated below — not a bad starting guide.
2. Break the pattern and rid our world of the viral form of predatory capitalism that has a stated goal of maximizing profits regardless of the social and environmental costs.
3. Bequeath a world to future generations that is headed toward sustainable, just and peaceful societies for all of us.
4. Join organizations that represent your passions, support them with your energy and/or money.
5. Use materials that are environmentally and socially responsible.
6. Support politicians who are in favor of the environment and will enact changes to protect it for future generations.
7. Vote in the marketplace for companies committed to doing the right thing environmentally and socially.
8. Let leaders know you want wholesome food, clean water and air; send emails — they do count, big-time.
9. Demand that every person on our planet has access to clean air and water, sufficient food, clothing and shelter, health care and a decent retirement.
10. Support companies that sell organic and local foods and operate on the basis of making profits but only while creating a sustainable, just, and peaceful world.