Scientists studying sediment cores in a remote Arctic lake found predictable, natural causes of climate change over the past 200,000 years.  Then something shocking happened.  The core sediment, starting about 1950 has been rather unnatural.  At this time the earth should be cooling a bit. Not warming.  This is not an opinion. This is science.

http://www.sciencedaily.com/releases/2009/10/091019162929.htm