If you think a climate skeptic has raised a legitimate scientific point or question, first check and see if it hasn't already been treated adequately at one of the following sites (9 times out of 10, there is already a good scientific answer to the question being asked):
Also, the following sites maintain lists of climate skeptics and trace the sources of their funding (usually the oil or coal industry), their activities and offers rebbutals to their claims:
Questions to ask yourself when you hear or see something that purports to "disprove" human caused global warming:
§For example an article in Science 306, no. 5702 (December 2004) p1686 counts 928 papers published in peer review science journals between 1993 and 2003 with the words 'Climate Change' in them. NONE of them disagree with the consensus that humans are causing climate change. A similar survey between 1988 and 2002 of media stories (non-scientific journals) about global warming counts 53% of the stories as giving equal weight to deniers of climate change (Global Environmental Change 14 (2004) p125). Articles in the popular press don't reflect the scientific consensus.
According to a report by the Union of Concerned Scientists, "ExxonMobil has funneled nearly $16 million between 1998 and 2005 to a network of 43 advocacy organizations that seek to confuse the public on global warming science."
James Hoggan in his book Climate Cover-up mentions the following organizations as being supported by the fossil fuel industry and deniers of human caused climate change (most are lobby or PR companies against cleaning up CO2 emissions). Feel free to verify or refute his claims: The Advancement of Sound Science Coalition (TASSC); American Coalition for Clean Coal (ACCE); American Energy Power; American Enterprise Institute; American Petroleum Institute; Americans for Balanced Energy Choices (ABEC); Asia-Pacific Partnership on Clean Development and Climate; Information Council on the Environment (ICE); Center for Energy and Economic Development (CEED); Competitive Enterprise Institute; ExxonMobil; Fraser Institute; Friends of Science; George C. Marshall Institute; Greening Earth Society; Frontiers of Freedom Institute; Global Climate Coalition; Heartland Institute; High Park Group; Intermountain Rural Electric Association; JunkScience.com; Natural Resources Stewardship Project; Australian Climate Science Coalition; New Zealand Climate Science Coalition; Oregon Institute of Science and Medicine; Strategic Lawsuit Against Public Participation (SLAPP); U.K. Scientific Alliance; Wester Fuels Association.
Naomi Oreskes and Erik M. Conway in their book Merchants of Doubt document the role of a small group of scientists associated mainly with the George C. Marshall Institute in diseminating misleading and false data about human caused climate change. The George C. Marshall Institute (which has recieved money from Exxon-Mobile) also worked with the tobacco industry to deny that smoking and second hand smoke cause cancer, lobby for the Stratigic Defense Initiative, and deny that CFCs caused the ozone hole.
There are around 30 scientific organizations (national and
international) which have issued statements supporting the idea that humans are
causing global warming: http://gristmill.grist.org/story/2006/11/13/221250/49
A list of scientists who oppose the mainstream scientific views on global warming can be found on Wikipedia: http://en.wikipedia.org/wiki/Scientists_opposing_the_mainstream_scientific_assessment_of_global_warming