I recently caught the "Coast" interview with Dr. Roy Spencer, who I guess would describe himself as a global warming skeptic. I was impressed with his argument which, on the surface, is reasonable: that we can't demonstrate a strong causal link between the rise of atmospheric CO2, and the apparent rise in relative temperatures in the Northern hemisphere. I personally "believe" in science and I am willing to be persuaded by a well-reasoned scientific argument... And as Dr. Spencer made his case, I found myself rooting for him. But I was ultimately unpersuaded, for a couple of simple but profound reasons.
First, I think that the "global warming" debate is mis-framed. The issue is not that the "rise in CO2 levels is causing the weather to get hotter." To me, the issue is that "the increase in atmospheric CO2 levels is resulting in unforeseeable but damaging changes to the ecosphere." Example: a measurable increase in oceanic acidity, due to the declining inability of the oceans to absorb increasing amounts of atmospheric CO2. This increase in acidity has been linked to coral reef die-offs and other imbalances in the ocean. The most apparent explanation for this phenomenon is the increase in atmospheric CO2, which, presumably, did not rise all by itself.
Second, the sea level is also rising, noticeably, and this is already causing problems along the American east coast, as salt water is encroaching onto the mainland and killing off coastal grasslands. The simplest (as in Occam's razor) explanation for this sea level rise is offered by the global warming "proponents."
Fundamentally, the increase in relative temperatures predicted by the global warming models is the least of our concerns. Even the debatable increase in "weird weather" is not especially problematic (although this is predicted by the same models). But if the oceans die, then so do we. And if the sea levels rise precipitously, civilization will be affected.
Ultra-hot summers and squirrelly weather events tend to alarm global warming believers, because they intuitively recognize them as harbingers of events more ominous. The skeptics would do an invaluable service to the world by furnishing irrefutable evidence to the contrary.