But IS it a controversial issue? Actually, NO, it isn't, not even remotely. Then, why is it so often debated on the news or in political discussions? Well, I think there are probably a few reasons for this. The first is that perhaps any given media outlet has a particular agenda to enforce - so, for example, they simply ignore the facts that the Earth IS in fact warming.
More likely though is that there is the illusion of debate and disagreement between scientists about this issue. The problem is that while, yes, scientists will often disagree on particular issues, this is no longer one of them. Yes, in the past, it was under debate - though, as I explain below, "debate" isn't really the right word. There is now overwhelming consensus in the scientific community (in particular, among atmospheric scientists) that global warming does exist and that it is in fact caused by us!
But what does this mean, "overwhelming consensus"? Does it mean a bunch of scientists got together one day and voted on whether or not man-made global warming is real? The answer is no. Many people don't understand the meaning of scientific consensus. I'm not blaming the layperson here - the blame could be put on our education system for not properly teaching students the way that science works (see here for a scary but excellent story related to this) or it could be put on scientists for not doing a better job at communicating how we think and work (though, I tend to think we are doing the best we can given the little money that we get for education and public outreach!).
Scientific consensus basically means that there has been a LOT of scientific research done and all of the results point to the same answer. It is not the same as debating whether or not we should raise or lower taxes by a certain percentage. A better analogy would be us knowing that the Sun will rise every day. Why? Because it has over and over again ever since the birth of our planet, and we understand exactly why (the answer being the rotation of the Earth). The data is there, the event is predictable, and yes, every day the prediction of the Sun rising is accurate.
The same is true for global warming. Yes, you can always find scientists who disagree with the results and have their own ideas for what is happening. However, they are very rare - there are still scientists who contest the idea of our universe being created via the Big Bang! All of the data, all of the research, all of the papers published point to the same result - man-made climate change is real.
And no, this post is not some sort of ploy to get more money from the government - hell, I don't even work on climate science! This post is here to educate people that if we don't do something about global warming, our coastal cities could very well look like this in the not-too-distant future:
Not to mention many many other environmental disasters (some of which we may already be feeling!).
Well, this post has gone on long enough. There is a lot more I could say on this issue, but for now, I refer you to Scientific American for more information. And for the love of God, do NOT get your information from biased media sources like Fox News or MSNBC.