You just have to laugh at anyone who says that climate change doesn't exist, but some people do make that statement. As tiga says, the earths climate is constantly changing. It is believed that the earth started as a frozen mass, since then the poles have been tropical rainforests and we have been through ice ages. (It's like people that say they don't believe in UFOs - people who say that don't know or don't think about what a UFO actually is.)
The real questions are, has the activities of man hastened the change in climate and can we actually make any difference by changing these activities?
Does the science actually stand up to the claims being made by either side of the debate? To be honest, I haven't looked into it deeply enough, but what I do know is the debate is being hijacked by people who have a barrow to push and the bottom line is always the mighty dollar. One of my favorite quotes is from the recently departed Michael Chrichton,
"Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled. Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you're being had.
Let's be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world. In science consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus. There is no such thing as consensus science. If it's consensus, it isn't science. If it's science, it isn't consensus. Period."
This may seem cynical, but he is right, science is not a democracy, it is the search for truth. It is important to make an informed decision based on the available data rather than just 'every one says so, so it must be true'.
When certain entities have a vested interest and enough money, they can influence science through sheer weight of numbers convincing the masses of something, that will ultimately lead to the filling of the coffers of these entities.
It has already happened with modern dietary advice, pushed by large food manufacturing companies and pharmaceutical companies creating illnesses where there are none, just sell their products. The end result is a population becoming sicker and more dependent on drugs.
Sorry, taking this elsewhere, just trying to make a point.
Personally, when an specific interest group, say the coal industry, or on the other hand the nuclear power industry, makes claims about climate change I basically ignore them because they have so much at stake in making their claims. I know it doesn't mean they are wrong, but to me they loose a bit of credence because of possible conflict of interest.
Then we get governments, hijacking science to promote their own agendas. Of particular relevance is the claims made today by a CSIRO scientist that he has been censored from publishing a paper that contradicts the government policy on climate change.
http://www.abc.net.au/worldtoday/content/2009/s2730523.htmAlso today we the hear the british goverment doing the same thing, albeit a different subject.
http://www.abc.net.au/worldtoday/content/2009/s2730523.htm (wrong link)
http://www.abc.net.au/am/content/2009/s2730179.htmThis is a prime example of the government trying to control the science to fit their policy, rather than forming policy based on the science.
But, back to climate change itself. I have heard people quote figures saying that the temperatures have not actually changed that much in the last 50 years or so. I have even heard one person claim temperatures, world wide, have actually dropped. (makes me think of the claims a few years ago that global warming would lead to an ice age)
This same person claimed that polar ice caps ( he may have specifically mentioned Northern) have increased in the last few years. Yet we have some pacific atolls where they claim that rising sea levels are destroying their food cultivation areas.
And of course we then have the vast majority saying (or just most influential) that temperatures are rising and will continue to do so, but remember science is not a democracy.
While I wont say you are wrong tiga, but by using the economic damage reasoning, you are clouding the issue at hand. Yes it is scary to have a professor of science advising the government on climate change, but to try to counter the government's policy with economic reasoning is no better. You need to counter their science with solid science yourself, or highlight the fact that their science is not solid. Once we make our decisions solely based on economics, then we are well and truly stuffed, whatever the decision is.
Sadly, i don't think any one really knows for sure the answers to the questions, are we speeding up climate change and can we actually slow it down?
With all the time, money and resources each side is putting into the debate we would be all much better off if it was put into working out how we can adapt to a changing climate, because the climate is changing, always has changed and most probably always will. Sadly this will not happen, because the driving force behind most of humans decision making is money.
Just as a footnote, besides the economical argument, would it be such a bad thing if the world was to reduce the amount of pollutants we spew into the atmosphere? I'm sure that someone, somewhere could create an economic model saying the saving in health costs or something similar would outweigh the economic damage . Actually I think there may be claims about how the changing weather and more frequent and intense storms, floods, droughts, pestilence etc etc will be devastating to economies. So round and round it goes.
Just my take on things