well...that's a $64,000,000 question! Do you mean global dimming via suspended atmospheric particular matter? Because if you do, I think that that will be the least of out worries. As far as damage goes, well it all depends on what time scale you want to measure on. You see any system can withstand small fluctuations yet still maintain the characteristics of that existing system...it's when we get to the 'tipping point' and a system is forced to change due to various external and internal reactions caused by these various inputs that we walk into the unknown. Indeed, in the long run the planet will get along nicely without us humans but we cannot survive without our planet and the narrow band of environmental conditions that make it favourable for us to survive. Ultimately change is happening all the time, we live on a dynamic planet flying through space and time with a limited life span. If we choose to defecate in the nest, then this is what happens!
Somehow I think I may have got away from the point! We can minimize our impact on the environment...basically by trying to minimize our raw material and energy usage, recycling where possible, using renewable energy supplies and by more efficient distribution of energy and resources.
Our world is run by politics, our politics is run by big business and their money....until the big oil / energy multinationals figure out a way to create revenue from other sources other than fossil fuels, there will be little change, I suspect.
If someone could invent a room temperature, superconductor that is cheap to produce (and fusion might help!) then that would solve the worlds energy problems overnight. Sadly we are all bound by human nature...which, by definition takes along time to evolve! More reading:
http://www.world.org/weo/climate