Just thought I would put my two cents in on the whole global warming thing. Those of you who know me will not be surprised that I'm a bit skeptical of the claims of the doom-sayers. One of the reasons that I have trouble taking them seriously is the fact that they rely so heavily on climate models that have not shown themselves to be very reliable.
One of the ways in which we test climate models (or any models for that matter) is to initialize them with a known state from sometime in the past, then feed it the data we have for the interval between the start date and the present. In theory, if our model is accurate, it should spit out an endstate that looks very similar to what we observe at our current point in time. Very easy to see if we got it wrong - if our model predicts freezing temperatures in Florida in August, we made an oops.
So what makes me bring up this whole dreary topic? I happened to read this article today (hat tip: Instapundit). It seems that, contrary to what the computer models based on last year's hurricane season predicted, this year's ocean surface temperatures (the driving force behind hurricanes) are not only normal, but below normal in some areas of the world. Which means a quieter than usual hurricane season.
Does this mean global warming doesn't exist? Not necessarily, but it does point to the dangers of making certain assumptions. Number 1 - never extrapolate from a single data point. Just because ocean temperatures were higher than normal last year, doesn't make a trend. Number 2 - don't ignore the role of nature in the climate. The oceans and the atmosphere can be tremendously variable, completely on their own without any man made influences (hence the difficulty in developing accurate climate models).
My position on global warming is this - the climate of the earth is changing. But that also happens to be its normal state. This planet is in a constant state of flux, with cycles of warming and cooling throughout history, not a static system at all. The influence of man is just a drop in the bucket - compare the amount of energy added to the atmosphere by man against the total influx from the sun, and your calculator will probably return an error message because it can't show a number that small.
I also have trouble taking people seriously when they talk about the changes in the polar ice caps, and how they will flood our coastal regions in the next 100 years. Sometimes I wonder if these people graduated high school.
For instance, the ones who are worried about the North Polar ice sheets (admittedly, they are in the minority, but nonetheless can be vocal about it). I'll admit, the North Pole melting would inconvenience more than a few people, not to mention the loss of a unique habitat for many animals, but it is not going to change the levels of the earth's oceans. THE ICE IS ALREADY IN THE WATER. Remember Archimedes? An object displaces the same amount of water that it masses - so a million ton iceberg will displace the same amount of water as a million tons of liquid water. Net ocean level change - zero. (Don't believe me? Try this - float a block of ice in your bathtub. Measure the water level before it melts, and after. Unless your drain leaks, it'll be the same.)
OK, on to Antarctica. Now here, we have a more serious situation. Most of the ice here is on land, so melting that WILL affect sea levels worldwide. By up to 50 meters, if estimates of the total volume are correct. And recently, we've heard about how the eastern ice shelf is melting faster than expected, dumping 36 cubic miles of water into the ocean last year. Of course, we only have one year of data on this, so remember rule Number 1 above - not a trend yet.
What you may not have heard is this - the interior of the continent is GAINING ice. That's right - 45 billion tons in the last year. Of course, same rule Number 1 applies here, but it makes you think doesn't it?
In the end, the planet is going to change - not really much we can do about it. Ask and paleontologist, and they'll regale you with all the changes in climate the earth has seen in the last 4 billion years. Trying to stop that is something akin to King Canute's fight against the tide, with about as much chance of success. Still, I can't help but feel that reducing our flow of pollutants into the environment is a good thing, if only from a cleanliness perspective. After all, its the only planet we have (currently), and we don't want the neighbors to think we're letting it get run down.
But I'm not about to panic yet.