Tsunamis and Risk
The catastrophic tsunami in South Asia is a prime example of a low-probability/high-impact event, as described in this excellent guest editorial in yesterday's Wall Street Journal (subscription required.) Mr. Posner also includes rapid climate change among the risks that share these characteristics. He goes on to discuss the challenges of addressing such threats before they occur, including the problem of getting them above the noise threshold of politicians.
There may be a more fundamental barrier, as well. There have been some interesting efforts to understand how and why people gauge risks improperly , including those of more common threats, such as smoking, car accidents, and environmental carcinogens. While the root-cause may be psychological, or even evolutionary, it still ought to be something that we can overcome, just as an individual with dysfunctional neuroses can overcome them with proper treatment. Without being alarmist, it should be sobering to contemplate potential disasters for which no global relief effort may be possible after the fact, because all regions were affected or the most capable responders were overwhelmed at home.
One of the biggest arguments I have with climate change skeptics is their insistence on an unrealistically high level of certainty concerning the likelihood of global warming and its consequences. When you consider the extreme effects that are possible, dwarfing what we've just seen in the Boxing Day Tsunami, they justify a sizeable effort to delay, mitigate, or perhaps even prevent them entirely, even if the cost of doing so is significant.