Well there seems to be general consensus among scientists that there is global warming.
Yet there is still debate within the general community over whether global warming is happening or not, and even among those who will concede that the globe is warming, some will argue that it cannot possibly be induced by humans. That we are too insignificant to have an impact on the planet. This to me is a ridiculous argument, there are many parts of the world where you can see the physical impact that pollution has on the atmosphere. And furthermore, I have seen a documentary where astronauts have talked of the lit up planet at night, the lights being city man made lighting.
This page has some incredible photos which show that.
I have always felt that whether you believe it or not, I would rather be on the cautious side and make changes towards a greater use of renewable energy sources. and be wrong, than sit back and do nothing and risk inflicting catastrophic damage on the earth’s atmosphere which may very well be reversible. There may be other planets in the universe which may be inhabitable, we have yet to discover them, nor do we have the means of getting there, so we really need to take care of this wonderful planet.
This youtube video explains things in a very thought provoking way.