By now, the predominant position of climate change denialism has shifted from "It isn't happening" to "Humans didn't do it".
Convincing this camp deniers is not enough to save us, though, for there is a second, more widespread and dangerous form of denialism in play.
The second climate change denialism: Denial of the gravity of the situation. The belief that climate change can be stopped with changes to our lifestyles and consumption.
While this may have had relevance in previous decades, the time for such gentle measures has passed.... The Earth is near (or past) the edge of runaway global warming.
The two camps generally share a common acceptance that the Earth is heating, leaving which leaves us with the problem: How can we cool it?
I believe the answer is to be found in Geo-engineering: massive projects intended to support the Earth's coping mechanisms and reduce solar input.
Geo-Engineering has been dismissed by many environmentalists as being a form of denialism, and they see it as a distraction intended to delay economically unpleasant international treaties.
To the contrary, I suggest that Geo-engineering is our only hope, and we need to get started yesterday.
The different GE proposals have varying benefits and shortcomings. Probably we'd need to use multiple methods. Here is a sampling to give you an idea.
Solar Radiation management: Sheilding ourselves form the suns rays, using everything from particles deliberately dispersed in our atmosphere, to having a massive space mirror positioned between ourselves and the sun. We'd only have to reduce the Sun's output a few degrees to make a difference. Concepts to increase the Earth's reflectiveness by painting rooftops white is a (insufficient) variation upon this them.
Ocean Nourishment: Increase Oceans' ability to absorb/process CO2 by giving ocean plant life a nutrient boost in the form of iron supplements.
More reading on Geo-engineering proposals: http://en.wikipedia.org/wiki/Geoengineering