All the arguments aside. This is a particular interest of mine, and something I'm starting a career in, so that's your grain of salt. Admission: I only skimmed the thread. Keep that in mind when you rip me apart. Thanks!
(1) Most of the ways people deal with this are talking and not acting, particularly the rock concerts that were mentioned. But if everyone did seriously just use fluorescent lightbulbs instead of incandescent - that's actually quite a lot from a little. So the energy wasted on a rock concert - IF it worked - is worth it. Energy efficiency is like voting. Nobody does much, but it's all in the aggregate. Unfortunately, we live in a world where talk/appearance rules over action.
(2) There is scientific consensus and there is a reason there's consensus. Scientists are trained to look at data, first and foremost, and the climate change models that people are computing are consistent with the temperature rises since people started burning fossil fuels. Of course, these are complicated computations and I don't do simulations, but assuming they have their basics right (and considering how much money there is to be made attacking these simulations - I buy it) then there's reason to think it might be right.
And! I know the models are simplified. But there's a reason to develop better computers. Fluid dynamics and global modeling are some of the nastiest systems to solve. If anyone is familiar with Lorenz's butterfly, here's a moment to consider it.
NB: Yes, there have been similar rises in the past. Yes, it could be natural. It also might not be. And either way, it's not good for humans.
(3) Those of you who mentioned China and India are spot-on. That's what's really scary, and also murky in terms of value. Is it the right of those in the West to say don't develop 'cause we already screwed up the world? No. Which is why we need more money/effort towards developing better technology so that development doesn't need to add to our carbon count. There are studies in progress and there is work being done jointly with those countries, but not enough. This is a great place to really contribute...
(4) Maybe for a lot of people it is like religion. It shouldn't be. It's a simple cost-benefit analysis. If it's wrong, and the earth is heating up naturally, it's bad for us and there's nothing we can do. If it's right, then there is something we can do. Better to take action and be wrong than to do nothing and fry because we were stupid.