A compelling summation of where things stand right now in regard to climate change and the urgency of immediate action can be found in an article published in Rolling Stone magazine by Bill McKibben. It's definitely worth a read: http://act.350.org/signup/reckoning/
These links take you to several websites which can provide helpful information about the science of climate change.
clear and readable information about climate change and its anticipated impacts from the Environmnental Defense Fund
Resources on this Environmental Protection Agency site include a video introduction to climate change, a slide show about indicators in the U.S., fact sheets on different aspects of climate change, and FAQ's.
The Climate Change Institute of the University of Maine provides a link to a thorough and nicely illustrated Maine's Future Climate Report (2009).
At the site, click on "Global Warming Science" for a comprehensive discussion from the Union of Concerned Scientists.
This NASA site has a wealth of scientific information about climate change.
350.org discusses why 350 parts per million is a critical number for the health of life on earth.