We are Still In - This campaign sprung up in response to the Trump Administration's decision to withdraw from the Paris Agreement. Local and state governments, institutions, businesses, and other organizations around the country are pledging to continue their efforts to reduce emissions in compliance with the goals set forth in the Agreement, regardless of the official US position on it.
350.org - This might be the epitome of a grass roots movement that has gained serious moment in the climate change arena.
Yale Project on Climate Change Communication - incidentally, they link to an article called Global Warming's Six Americas which is very good and has previously been used as a required reading for this course. So much of the tension related to climate policy stems from communicating the risks and science to our policymakers. This Yale effort represents a big push toward bridging these gaps and ensuring that our elected officials are making decisions with the best available science on the issue.
Citizens' Climate Lobby - connecting citizens with their elected officials to enact real change - the squeaky wheel gets the grease!
Energy Action Coalition - this is a bit of a hub for the youth climate movement. This group is also responsible for having organized two big Power Shift demonstrations in recent years.
The Climate Reality Project - another advocacy nonprofit focused on achieving net carbon emissions.
The Climate Group - is a nonprofit which works specifically with government and industry leaders to utilize climate finance mechanisms to inspire low carbon growth and development.
These are just a few of the big ones. I'd encourage you to start locally and see what you can find in your area. Talk to your municipal government officials and find out what your community is already doing (or should be doing - with your help!) to move toward a low carbon economy.