The factors contributing to "global warming" are actually an effect of a sum total of a lot of things. Carbon dioxide emissions are definitely not the only contributor. But the general (and unfortunately myopic) perspective is that CO2 = global warming. It doesn't help that all that campaigning seems to amplify this and delude the issue further.
However, IMO, there is also the danger of saying that "Global Warming is NOT man made". This will throw us into a false sense of security and complacency, that it is okay to live the way we are living now. We will only spiral down into polluting and destroying further. Is it just me, or is it only recently that, with all this talk on global warming, a lot of people suddenly become interested in environmental issues? I'm seeing it as a catalyst or spark, and it somewhat works.
As resources for food, water and land dwindle, we look at global warming as the problem. Whether it is true or false, it is still a subject of debate. But because of it, we are letting it be the reason to see how important the need for a new, clean and sustainable energy is, and how important the ecological system is.
Yes, a lot of people believed that there seem to be some climatic changes recently that will eventually affect the resources we need to survive on this earth. So we need to adapt to it and not add on to the pressure of what is already fragile. We need to think of solutions to address certain problems that MAY be contributing to this issue. And in general, the steps we are taking for the most part ARE helping to the environment, global warming or not, which is a good thing, yes?
As the population of the earth grows bigger, it's no longer about forcing our environment to adapt to us, but instead, it's now about us adapting to the environment. The latter being a tough act to do. The need for food, water, land and energy increase in ratio to the global population, but we are confining ourselves further away from direct interaction to the eco system (concrete housing, internet, phone orders, courier services etc). We are not hunters and gatherers like our ancestors. We no longer have the same kind of respect and appreciation anymore, cos we are not directly involved with the eco system. If it takes a global fear such as global warming to get us into that scope, then I'd say why not?
Two cents.
