Global warming is crap. When you look at how the conclusions are reached, you realize it's all guess work. If anyone were really honest about it, they'd admit we possess a staggering lack of data and understanding when it comes to environments. If someone tells you the world is warming significantly, they're full of crap. If someone tells you the world is cooling, they're bull-ing. If they say the world is static, they're just stupid. If they even begin to speculate about the cause, they are undeserving of any respect whatsoever.
We don't know, but the 'climatologists' (meteorologists minus the already low reliability) seem loathe to admit that much. Additionally, much of the "green" folk believe in this view that if we leave nature alone, it'll do just fine.
IT WON'T.
Firstly, we aren't special enough to be separate from nature. We are in the ecosystem, so we are, necessarily, involved in nature, and are not unnatural in any way. An apartment complex is as natural as a termite mound.
Secondly, one merely needs to study the history of environmental management of Yellowstone National Park (or any similar situations, if you can find 'em) and its record of failed environmental management under the "leave it alone" philosophy as well as under active management philosophies.
We don't know what we're doing, ever, with the environment. We haven't the slightest understanding about dynamic environments.
If that upsets you, sorry, but you'd better learn to deal with it.
Global warming is a scientific hypothesis, even if it is soft science (can't be tested [realistically, and in under a few decades of time spent on observation]- computers are models, not actual observations, by the way). It's certainly worth studying, but it's far from anything meriting urgent political or social action.
Socially, it's the latest crisis sold to us by varied groups under the guise of science, and I find that despicably shameful. It tarnishes the name of science.
As a note on the term "climate change," before someone uses it: There's definitely climate change, but to say the climate is changing is to say absolutely nothing interesting.
It's never been static, it never will be static, and it isn't static.
You may as well say that you've discovered carnivorous predators, for all the meaning "climate change" has.
Finally, before someone trots out a model they think will convince me, I ask everyone to recall Lord Kelvin's estimation of the Earth's age (Abridged Version: He used thermodynamics to set it between 20 and 400 million years (actual is 4.4 billion or so), and his math was flawless, but he failed to account for heat generated by pressure or radiation, so his model wasn't accurate), and its ramifications for mathematical models describing systems we don't well understand, the Earth and its climate among them.
Which, you know, makes dictating national and international policy on such models somewhere between foolish and dangerous.
If someone tells you they know the Earth is warming, they're full of crap, just as they are if they tell you it's cooling or isn't changing. The only honest claim is one of confusion, ignorance, and climatology's relative immaturity as a field in science.