It doesn't appear with current trends that we will see more politicians and "deniers" dismissing AGW in the future. Considering that many governments/politicians the world over have already created numerous policies to limit the output of human sourced GHG's. The trend is towards more regulation, taxation and restrictions - not less.
This is why we continue to see auto-manufacturers focus on their reduced CO2 emissions...or companies touting their use of solar/wind/green energy sources...tax breaks for solar panels in residential/commercial structures...tax breaks for green cars etc...etc..etc...
This isn't because the politicians of the world are deniers. These are policies set in place to encourage the use of green energy.
A century from now we'll have far superior data, models and evidence to support, contradict or even possibly create new hypothesis about AGW, climate change and GHG's.
I know I know by then it will be "too late" and the world will fall into some deadly cycle of becoming the next Mars or some shit like that.
Ultimately I think there are some that dismiss AGW, some that accept it but are skeptical of government reactions to the phenomenon, others that claim the sky is falling and others still that think its a big hoax/conspiracy.
We'll see what comes...humans are a rather inventive species.