The current Government implication with the Global Warming frenzy has much more with the desire to have more control and higher taxation than any real desire to fix perceived problems.
While your last statement seems more of a personal outlook than historical analysis, that is exactly where the green movement has had an effect. While some (present company included it seems) decry rising costs of environmental protection, the fact that it can be considered at all is due to the fact that many others recognize the need for rising costs due to their perception that the alternative will cost more.
It's a passive role for a movement, sitting back and paying out rather than marching on city hall and demanding change, but it's probably more important.
The perceived nature of the crisis is of an interconnected system of interconnected systems. The more systems you can rope in at one go, the more likely you are to have an effect on things. Therefore effort made at the national and international level (with pressure from green lobbies) will always have more success than relying on ballot initiatives and petitions.
Without the public support for a green movement, some things probably would still get done out of blatant necessity, but not nearly as much. People have to be willing to accept change, and it's that mindset that the green movement has instilled in a sufficient percentage of the people to make that change possible.
But just another point so this is somewhat more about alt hist than just poly sci, I think the "War on Science/War on God" dichotomy might not develop. Environmentalism vs Capitalism was a key oppositional in the formation of a recognizable front. Without that connection, we'd still see the morality patrol and the rise of the Christian Right, but a lot of the dogma the Left could muster came from stewardship and focusing on this world instead of the next.
So less of a coherent response from the Left might mean an easier rise for the Christian Right, but there's also less perceived opposition for them to push against and less call for them to rally the faithful to their banner.
Maybe Reagan-style pro-business nationalism sticks around longer and religion doesn't differentiate.