Limate Change a man made or a natural occurrence?

This is a fairly straight forward research paper discussing the cause of climate change. To what extent is it man made or natural occurrence etc..
Please try to use as many of the sources i provide for you. You may use your own sources obviously but Id rather it be a Print source rather than a web source. It should be written in size 12 font.
Here are the sources you might want to use (please try to use at least half of them):

Clinton, Bill. Interview by Andrew C. Revkin. a?Clinton on Climate Change.a? New York Times. New York Times, May 2007. Web. 25 May 2009.
Gore, Al. An Inconvenient Truth: The Planetary Emergency of Global Warming and What We Can Do about It. New York: Rodale, 2006. Print.
Jarman, Melanie. Climate Change. Halifax: Fernwood Pub. ;, 2007. Print.
Miller, Debra A. Global Warming. Detroit: Greenhaven, 2008. Print.
Pringle, Laurence. Global Warming. New York: Arcade Pub., 1990. Print.
Simon, Seymour. Global Warming. New York: Collins, 2010. Print.
Watts, Robert G. Global Warming and the Future of the Earth. San Rafael, Calif.: Morgan & Claypool, 2007. Print.
GlobalWarming.org. Cooler Heads Coalition, 2007. Web. 24 May 2009.