350 is a global network using online campaigns, grassroots activism, and mass public actions to “oppose new coal, oil and gas projects, take money out of the companies that are heating up the planet, and build 100% clean energy solutions that work for all.” Their website lets you search for climate campaigns and groups in your community.
Climate Hawks Vote
Climate Hawks Votes identifies and supports US politicians who will be aggressive climate leaders. Become a Climate Hawk voter!
Leadnow does grassroots organizing and campaigning around climate justice in Canada.