The argument over what causes climate change is still ongoing, however the recent channel 4 documentary ‘The Great Global Warming Swindle’ has brought new support to the camp of believers who think climate change is a natural phenomenon: http://www.channel4.com/science/microsites/G/great_global_warming_swindle/

The main arguments in current circulation are listed below:

The Earth's climate is always changing and this is nothing to do with humans.

http://www.oneclimate.net/2007/04/17/myth-climate-variation-like-this-is-usual/

http://www.royalsoc.ac.uk/page.asp?tip=1&id=6230

Rises in the levels of carbon dioxide in the atmosphere are the result of increased temperatures, not the other way round.

http://www.oneclimate.net/2007/04/19/myth-carbon-dioxide-doesnt-cause-global-warming/

http://www.royalsoc.ac.uk/page.asp?tip=1&id=6231

http://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores

Computer models which predict the future climate are unreliable and based on a series of assumptions.

http://www.royalsoc.ac.uk/page.asp?tip=1&id=6232

It's all to do with the Sun - for example, there is a strong link between increased temperatures on Earth with the number of sunspots on the Sun.

http://www.royalsoc.ac.uk/page.asp?tip=1&id=6233

http://www.realclimate.org/damon&laut_2004.pdf

The climate is actually affected by cosmic rays.

http://www.royalsoc.ac.uk/page.asp?tip=1&id=6234

http://www.realclimate.org/index.php/archives/2004/12/recent-warming-but-no-trend-in-galactic-cosmic-rays

The scale of the negative effects of climate change is often overstated and there is no need for urgent action.

http://www.royalsoc.ac.uk/page.asp?tip=1&id=6235

Global Warming Predictions 2070-2100

Image by Global Warming Art