You may find these links useful:
NASA – The Earth’s vital signs
Centre for Climate Change Economics and Policy
Harvard University – Tackling climate change
MIT – Conversation on climate change
George Monbiot – An informed and engaging point of view
Noam Chomsky – Talks, Videos, Books on all sorts of important questions
TED Talks on climate change – Fascinating, short talks by the world’s experts
Intergovernmental Panel on Climate Change (IPCC)
IPCC Summary for policy makers (An excellent summary of the science)