Well everyone needs to do a lot of things, so? Does that mean they do? If some country was to straitjacket it's citizens to strict eco rules, at the cost, of say, a quarter of their wealth when most other nations did not, would it do any good? Of course some could say, well it did the world some good..
Um, except that isn't what would happen. The first thing to point out is that moving to a low-carbon-emission economy requires
tremendous innovation and production. An economy that is actively pursuing a green-energy future, in other words, is a vibrant economy.
In the end, it
may mean that the eventual cost of goods and services will be a couple percent higher than you get in a greedy economy. But I doubt it. The problem is that fossil fuel emissions have all sorts of nasty effects that cost us money in other ways. The pollution from burning oil and coal, for example, causes various health problems that we pay for in our medical insurance bills. In fact, those medical bills are so expensive that they outweigh the cost of the fuel
by a factor of three.
This means that, for example, when you go to the gas station and pay $2/gallon for gas, the true cost of that gas
to you is actually higher, because you end up paying he medical bills for all of the people damaged by air pollution (even if you don't get hurt yourself).
Moving off of fossil fuels, then, actually
saves us money. And not a small amount. We would have a better economy, not a worse one, if we moved to a more sustainable one.