In the global debate that rages (increasingly loudly) about the environment, people are often asked whether they are an optimist or a pessimist. Your average enviro-awareness crusader is easily cast as a pessimist doomsayer and your techno-salvation guy as an optimist. On the face of it this distinction might be true, but the important thing is that both are acting on the evidence, and so both are likely to bring about positive change - the former helping to reduce bad practices, and the latter to introduce new good ones.
Rather than an optimist vs pessimist question, a more relevant distinction to make would be between those who do something about the problem and those who don't. Those who don't could fall on either side of the fence as well - pessimists who fail to act are defeatists, and techno-salvation believers are just hot air unless they really support the technologies that they think have the potential to divert the world from asphyxiation. I suspect many techno-salvation types are just hedonists or narcissists who have latched onto the idea of techno-salvation so that it doesn't spoil their fun.
So whether you are pessimist or optimist on the future of the enviroment, it is important to at least speak up, or even better, do something. Don't just resign yourself to it all and go live in the countryside (where you will likely need a car). The issue of global warming may prove to be the most serious test of democracy yet. Let's make it work.
You want change?
Step 1) do what you can yourself to mitigate problems / raise awareness
Step 2) support organizations and groups that do the same thing on a bigger scale
Step 3) if there are none, form one
Step 4) support elected representatives who do the same
Step 5) if there are no elected representatives doing that, or you are frustrated with the pace of change, run for office yourself.