It's hardly a strain to imagine that the addition of 2 trillion tons of carbon to the atmosphere since the beginning of the industrial revolution would affect the atmosphere and climate. But you know what else emits a lot of CO2? Volcanoes! And they're natural! Just one volcano -- Krakatoa -- put so much debris in the atmosphere in 1883 it actually created a global winter that lasted two years! And that's winter which means cooling, not heating.
But yeah, human-generated carbon still outweighs volcanoes 60:1, and the Earth has been steadily heating up much as climatologists have projected for years, although unfortunately even faster than the models suggested just a decade ago.
Humans evil? That's a value judgement. Simple fact is that humans are the dominant species on earth, consume a vast amount of natural resources (increasingly so as standards of living rise), and have grown from 1.6 billion to 8 billion in population since that Industrial Revolution. It takes a lot of contortion to pretend we aren't massively affecting the global ecosystem. Fossil fuels bad? Another value judgement, but in terms of the economic, political, and environmental consequences of our petroleum dependence, it makes perfect nonpartisan sense to pursue alternatives. I'm happy to thank fossil fuels for all they've provided, and welcome their participation in a lesser role.
You do know that when you say "I think not" the you in question is Archy1221, right? And that other folks know a lot more than you do because that's their job?