The New Scientist (May 16, 2007) compiled a list of some of the topics surrounding climate change, notions that are sometimes used to refute the mainstream science findings. Some of these are generalizations that are not supported by observations and/or models, and others are alternative explanations, such as solar radiation. They may not all be "myths", but they have led to mythunderstandings (sorry). This piece has some very useful illustrations of climate variables over time. Check it out!
The 7 biggest myths about climate change