Do you believe smoking causes cancer?
If the answer is yes, then I have to question why you wouldn't believe in human caused climate change.
http://www.scientificamerican.com/ar...d-lung-cancer/
http://whatweknow.aaas.org/wp-conten...at-We-Know.pdf
Why would you believe the scientific community consensus in one respect but not another?
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Note: When I say "you" I mean in a general sense I'm not referring to anyone in this thread.