If you are particularly interested in the temperature reconstruction of the last 2000 years (e.g. the “hockey-stick”), you can read this report from the National Academy of Science in response to a request from Congress. You can download the report for free.
Citizens’ Climate Lobby is “a non-profit, nonpartisan, grassroots advocacy organization focused on national policies to address climate change and which works towards the adoption of fair, effective, and sustainable climate change solutions.” They have chapters across the nation and around the world. https://citizensclimatelobby.org/