And yes, I believe man can and should change much to lessen the CC problems.
For yourself - Some day if you dare or should go to the country or the middle of the ocean - say a cruise to the Caribbean - note the color of the sky at dawn or sunset and see the dense layers of smog that sit in the air for as far as the eye can see. You'll know it's there because of the odd rust/brown color in the reds and oranges the sun creates in our atmosphere. Note, that's what covers the earth and it's not because of a volcanic eruption somewhere. And if you don't believe man can influence global climate after that, well, figure it out.