Niall Ferguson asks this age-old question in relation to Katrina. Voltaire would have used it as evidence of Gods non-existence; Leibniz would have claimed it was all part of some larger plan, incomprehensible to the limited vision of human beings; John Wesley would have cited it as proof of Gods judgment of sinners. Few Christians today will echo Wesleys line, but some Muslims are already doing it, talking about "Private Katrina" as a recruit in the "global jihad":
It would be hard to get more tasteless. Yet the same underlying impulse — to interpret the disaster as confirmation of ones own ideological position — was at work among many American liberals too. Opponents of the war in Iraq were not slow to point out that National Guardsmen who should have been on hand to rescue hurricane victims were instead failing to prevent lethal stampedes in faraway Baghdad.
Ferguson concludes that it is pointless to try to find moral significance in natural disasters:
Natural disasters — please, lets not call them "acts of God" — killed many more people than international terrorism that year (according to the State Department, total casualties because of terrorism in 2003 were 4,271, of whom precisely none were in North America).
On the other hand, disasters kill many fewer people each year than heart disease (around 7 million), HIV/AIDS (around 3 million) and road traffic accidents (around 1 million). No doubt if all the heart attacks or car crashes happened in a single day in a single city, we would pay them more attention than we do.
As Voltaire understood, hurricanes, like earthquakes, should serve to remind us of our common vulnerability as human beings in the face of a pitiless nature.