A brief search of the scientific literature shows there is no dispute about climate change, and only mild disputes about the absolute cause (although there really isn't any debate that it is, at least, partially human caused; see links). I have linked a few articles from the peer-reviewed scientific literature:
Some consequences of climate change:
http://pubs.giss.nasa.gov/docs/2008/2008_Rosenzweig_etal_1.pdf
Review paper on human caused changes to the earth--includes a section on how CO2 from burning fossil fuels alters the global carbon biogeochemical cycle:
http://magmo.typepad.com/VitousekHumanDomination.pdf
The role of external forcings in temperature patterns:
http://www.sciencemag.org/cgi/content/abstract/290/5499/2133
Model that shows the sun is response for warming trends in the early 1900's, but anthropogenic sources must be included to account for current warming trends:
http://www.cgd.ucar.edu/ccr/publications/meehl_additivity.pdf
Analysis of whether natural causes could counterbalance (or mask) anthropogenic warming.
http://stephenschneider.stanford.edu/Publications/PDF_Papers/BertrandEtAlfulltext.pdf
I think people refuse to accept anthropogenic climate change because of several reasons:
1) Politics: global warming has been blamed on a left-wing agenda and some people don't like this idea. People believe this is a hoax created by the liberals to redistribute wealth.
http://www.nctimes.com/articles/2007/03/03/perspective/17_51_132_23_07.txt
http://www.realclearpolitics.com/articles/2006/06/why_liberals_fear_global_warmi.html
2) The models are only moderately accurate. This is because of the scale and many factors that contribute to the global climate. A NASA/Goddard scientists recently wrote an article about this problem and the progress that we are making with our models:
http://pubs.giss.nasa.gov/docs/2008/2008_Rind.pdf
3) People are stubborn and refuse to accept responsibility for their actions.
4) Most people don't have access to the scientific literature: Please note which of my reasons are supported by peer-reviewed scientific literature and which are supported by political websites.