It’s hard to know what to say about the ongoing disaster in New Orleans (good coverage here). Good luck to all our readers there.

It sounds like it’s not going to be as bad as feared, which is some comfort. For a glimpse at how bad it could have been, read Mooney’s prescient AP piece from three months ago. And for a lament about the woeful lack of preparation, read his followup: "prescience sucks."

Katrina is sure to reignite the ongoing debate over hurricanes and global warming. A few thoughts on that debate below the fold.

Let’s take the following two premises — both argued repeatedly by Roger Pielke Jr. (see here and here) — as given:

  • There is no solid scientific case tying current hurricane frequency or severity to global warming. Global warming is widely expected to increase the severity of hurricanes and the frequency of severe weather events in coming years, but anyone who points at Katrina and says, "look, global warming!" is, to put it charitably, way out ahead of the scientific consensus.
  • If our primary goal is preventing hurricane-related deaths, slowing the rise of global CO2 emissions is about the slowest, most inefficient possible course of action. Almost anything else — improving coastal wetlands, training local disaster-relief personnel, building better sea walls — would save more lives, more quickly, for less money.

But. Let’s also remember the following:

  • When greens discuss hurricanes and global warming, preventing hurricane-related deaths isn’t their primary goal (though presumably all support it). Their primary goal is to raise awareness of, alarm about, and support for action on global warming, the ultimate effects of which will dwarf any individual severe weather event. If global warming represents the scale of disaster greens believe, then arguably the urgency of generating a large-scale response is great enough to warrant some fudging on strict rules of accuracy and precision. Many, many lives are at stake.
  • There will likely never be any bulletproof scientific link between global warming and any particular severe weather event. Global climate is extraordinarily, almost incomprehensibly, complex. Billions of variables are involved. All climate scientists can say for now (and this seems to me unlikely to change) is that global warming raises the probability that severe weather events will occur. Consider an analogy: Crime rates rise during heat waves. But no individual criminal is likely to say, "I robbed that little old lady cause it’s so damn hot." The reasons people commit crimes are many and varied. But this doesn’t cast doubt on the link between heat and crime.
  • Large-scale action on environmental issues tends to follow on the heels of dramatic events: the Cuyahoga River burning, Exxon-Valdez, Love Canal, etc. A cat5 hurricane like Katrina is nothing if not dramatic. It opens up a cultural space for dialogue and action at a time when getting the collective attention of the American public is extraordinarily difficult.

In the end, greens concerned about global warming face a choice. Do they stick to scrupulous standards of scientific accuracy, with all the hedging and qualifying that entails, at the risk of being boring and losing an opportunity to galvanize action? Or do they fudge a bit, propagandize a bit, indulge in a little bit of theater and showmanship?

And a further question: what role do scientists play? Are they, or should they ever play the role of, advocates? Or should the separation of green advocacy and science be strictly enforced?

These are tough questions, not as simply answered as many on both sides would have it.