Smog is manmade but with the correct air currents it would be another cities problem.
http://www.ace.mmu.ac.uk/eae/Air_Quality/Older/Clean_Air_Acts.html
Metropolis Water Act - dirty water is natural but I don’t drink it for one.
http://en.wikipedia.org/wiki/London's_water_supply_infrastructure
So where would I be now if none of this was done. More likely dead as I live near the docks in London.
I could go on but the examples above show on a small scale what effects we at least have on our own health in reflect of the environment.
I will concede there are companies that make money by waving the environmental flag as well as those that gain from saying we have no effect on our environment.
http://www.globalwarming.nottinghamshiretimes.co.uk/Scam.html contains a lot of information in respect of what you have said.
A lot of the site in respect of global warming use the Industrial Revolution as a the start of when we caused CO2 emissions to rise
What if crop burning caused the CO2 emissions to rise it could be argued that when fire was discovered we started our pollution of the planet (was an artical in natual geographic about it).
In the end I believe on the base of heath alone we should be concerned about our environment Impact don’t you ?
Flame » in reply to Atmosphere or Oceans?
Another prespective