The VAST majority of recognized (that's the important part) scientists all see the human impact. The 'proof' from the deniers doesn't come close to the reams of information being put forward by the others.
There was also a mini-scandal a few years back where a paper was published by the deniers and low and behold - the paper was financed by the oil and gas industry.
Ice core samples can be taken from the antarctic dating back 100's of thousands of years - in no time has there been as much CO2 in our atmosphere as there is now - and that pace is increasing exponentially. To think that man cannot change his environment is just plain silly. Look out your window and try to tell the world that man cannot change his environment.