The climate change proponents dominate the debate because, well, the facts are on their side. They dominate the debate in the same way that doctors and scientists dominated the debate over Big Tobacco.
Deniers aren't real skeptics, they're using rhetorical devices to attack the falsifiability and uncertainty of science. They use the very principles that enable science to determine fact against it in the realm of public opinion.
Here's the thing about science, Bob. Science welcomes people to question its conclusions - that's what the whole scientific process is about. But those questions have to logical, they have to be structured, and they have to actually make sense.
And, when all is said and done, the deniers have not yet produced a shred of real evidence that disputes the body of reseearch showing that human-based greenhouse gases are significantly changing our climate. The deniers cannot produce a competing hypothesis to explain the data we've observed and the information we have. They haven't done so for two reasons - 1), that alternative hypothesis where humans aren't causing this just isn't true, and 2), they don't need to produce an alternative hypothesis to obfuscate and introduce doubt into the public (not the scientific) debate, just as Big Tobacco didn't need real evidence to argue for years that we don't know cigarettes cause cancer.
Do you believe that smoking cigarettes causes cancer, Bob? Why or why not?