I realize that my opinion is far from the majority opinion (at least according to the news media), and I am aware of the fact that most of my friends disagree. If you'd like to comment, please don't use this message as a soapbox to present opinions I've had shoved in my face a zillion times over. Such replies will be deleted. If you want to convince someone of your political opinions, there are dozens of forums where such discussions are welcome.
That being said, my message:....
First off, the climate-change controversy is irrevocably tied up in right-vs-left politics. The environmental movement (for whatever reason) has aligned itself with socialist and even further left-wing groups, who use climate change as an excuse for promoting extreme left-wing policies that have nothing to do with the climate. Hence the reason why most "solutions" involve moving a lot of money around but without actually reducing anybody's emissions.
A great book on this subject is Blue Planet In Green Shackles by Czech President Václav Klaus. It discusses this subject far better than I ever could.
As for climate change itself, because of the political issues (not the least of which is that researchers who dispute the dogma find themselves unable to get any government funding - which creates a strong impetus to not even try to disagree) it is nearly impossible to find unbiased research. It's worth noting that the UN's Intergovernmental Panel on Climate Change (IPCC) released a report where the summary on the cover describes a conclusion that is not borne out by the body of the report. And when the contributing scientists objected, the IPCC refused to take their names off of the report. So not only don't we know what's going on, but we really have no clue how extensive this consensus might or might not be.
As you might have guessed by now, I don't agree with the IPCC or others who believe in man-made global warming. The book that most clearly explains my opinion is Unstoppable Global Warming by S. Fred Singer and Dennis T. Avery.
In this book, the authors present very solid evidence that although there is currently a warming trend, it is part of a natural cycle with a period of approximately 1500 years (which is based on the convergence of several independent solar cycles.) This cycle's most recent low point was in the early 16th century (during what's known as the "little ice age" - a period that officially ended in about 1850 - the point which most climate-change supporters use for baseline temperatures.) The previous peak was in the 8th century - the peak of the so-called "medieval warming period" where the polar ice caps were almost non-existent and Vikings had vineyards and dairy farms on what is today known as Greenland. The warming trend we are currently in will continue until approximately the 22nd century, where it will slow and gradually become a cooling trend. Human activity has nothing to do with any of this, human activity is powerless to stop it. Instead of trashing the global economy trying to stop nature, we should be spending our limited resources working on ways to minimize climate change's impact on human civilization - a task which is far simpler and more cost effective than trying to prevent the climate from ever changing again.
Of course, this opinion is not widely presented in either circle. Instead, you are asked to choose between "it's all humanity's fault and we have to fix it" and "the climate isn't changing". The third opinion of "it is happening but we can't do a thing about it" is lost in the noise. If you can't score political points, nobody cares what you think.