http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-1-1.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-... It may be worse than that.

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-1-1.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-... It may be worse than that... Those charts show higher levels of several greenhouse gases than has occurred in hundreds of thousands of years, not centuries.