At this point, even the harshest critics of global warming (like Gregg Easterbrook) are giving up on their argument that the planet is just going through some sort of a natural cycle. The evidence is overwhelming that the planet is warming due to human actions.
The few remaining people clinging to their belief that nothing is wrong have simply stopped debating. Much like Kevin Bacon's character in Animal House, no matter the evidence, they insist all is well.
But many of those global warming critics are now trying to re-frame the terms of the debate, shifting tactics and digging new trenches in the political battle, and environmentalists need to change with the times or risk being caught off-guard.
Republicans who once argued the planet wasn't warming are now admitting that the planet is warming, but that either there's nothing to be done about it, or that the costs of doing something are so high, they're not worth doing. Instead, we should "adapt to inevitable changes."
Corporations are now trying to duck responsibility by painting themselves green. General Motors, famous for being a prime suspect in the murder of the electric car, continues to flog its hydrogen car prototype as proof that it's trying to go green, despite mountains of evidence that hydrogen cars are nothing more than a red herring. And they're still fighting higher fuel economy standards (they haven't been raised in 20 years).
No matter the distractions, environmentalists need to stay focused on what's important. We've played a role in the planet's warming, and we have a role to play in helping return it to balance. It will take major shifts in energy usage and major advances in techology to help that happen. But we have to try. We're already seeing signs of the consequences of inaction.
UPDATE: Another tactic -- don't deny the facts of global warming, just accuse your opponents of being hypocrites.