While researching climate change I have discovered a host of new facts and observations. I have yet to synthesize it into something coherent, so most of it will have to wait. I will note a few interesting things though and then close with comments on science and policy.
Those of you who have seen Al Gore's An Inconvenient Truth (or turned on the TV or surfed the web) will likely have heard about two of global warming effects: increased hurricane activity and the drowning of polar bears. It turns out that while there is some truth in these claims, the reality is quite complicated.
Hurricanes are powered by warm ocean surface waters evaporating and then condensing, releasing latent heat. The warmer the water, the more evaporation, and therefore the more heat released to power the storm. As sea surface temperatures rise then, so should the number and intensity of hurricanes. Al Gore quite bluntly lays the blame for hurricane Katrina at the feet of global warming. Climatologists, however, point out that it is impossible to pin a local, specific event like Katrina as being caused by global warming. While it is true that some theoretical studies have linked rising water temperatures will increased hurricane activity, the observations are that the number of hurricanes have in fact not increased at all. What has increased is the relative number of intense (category 4 or 5) hurricanes. There has been some controversy over this claim, however, as our reliable records only go back around 30 years. In other words, how can we be confident that the number of intense storms has gone up when we don't have a reliable long term record to compare it to? In addition, several studies have shown that as the planet warms, wind shear over the Atlantic and East Pacific will increase. This atmospheric phenomenon prevents hurricanes from forming at all. Yet other studies have shown that this increased wind shear will result in less hurricanes making landfall in the U.S. So, the jury is certainly still out on exactly how global warming will affect hurricane activity.
As for polar bears, I have discovered that populations are indeed on the decline (down 20% or so in the last 30 years). While this is probably influenced by climate change and the decline of arctic sea ice, it is not yet true that we have found drowning polar bears because of a lack of sea ice. The study that seems to have sparked all the media interest (and led Al Gore in his movie to show a CGI clip of a polar swimming in an endless ocean searching for ice) is one where four polar bears drowned due to a fierce storm off the coast of Alaska. Not global warming; an intense storm. While it is hypothesized that the bears may have been swimming longer than usual due to less ice, Al Gore's portrayal hardly seems appropriate. This seems to be another example of misleading information around what will likely be a real issue. If global warming continues, polar bears will have to adapt or perish. It is disappointing though that the facts were twisted to support an agenda.
OK, so in this and the last three posts it will hopefully have become clear that much of the science surrounding past and current climate change is both complicated and tentative. So what should we do? There are those who advocate doing nothing in the interest of preserving our economy, and those who advocate radical change. For myself, the uncertainty of the science can be separated from policy decisions. Why? Consider our current source of energy, fossil fuels. These fuels formed during the Carboniferous period 300 million years ago. The processes that formed all of the coal and oil is slow, somewhat mysterious, and only seems to occur under certain conditions. This is why coal and oil are considered non-renewable resources. World population will likely hit 9 billion in the near future. Developing economies, like China's, are increasing consumption of fossil fuels at tremendous rates. Besides the fact that fossil fuel emissions are probably contributing to climate change, there is another perfectly good reason to develop alternative sources of energy: we are going to run out of fossil fuels (in as little as 30 years by some estimates).
You may have heard of Pascal's wager, a philosophical oddity that suggests that it is a better logical bet to believe in God than not to believe in God. After all, if you believe in God and you're wrong, nothing really happens to you when you die. But, if you don't believe in God and you're wrong, you may be sentenced to eternal damnation. Therefore, it is a safer bet to believe in God. Putting aside the merits of this theological wager for a second, consider the current crisis. If we act to stop global warming, and it turns out to be a complete hoax, what do we get? Some time and money will be spent, but we will also find ourselves with reduced pollution (fossil fuel combustion results in environmental damage besides global warming), zero dependence on oil of any sort (plus it will run out anyway), and the development of new, clean, efficient energy sources. Now, consider the flip side: if we do not act, and the less nice predictions about future warming are true, we could find ourselves with a host of problems, including: sea level rise, habitat devastation, increased floods and droughts, changing atmospheric and ocean currents, and others.
When it comes to modifying the Earth's climate with greenhouse gas emissions, an experiment in which the outcome cannot be predicted, it just seems to be to be a safer bet to start phasing out fossil fuels now and perhaps keeping reserves for emergency situations. I have called this "Gore's Wager" in the past, but as I find out more about climate change, the less enthusiastic I am about using his name. I'll have to think of something else...