The Post-Normal Times

Update 12/2/05, 9 pm: Jeff Masters/Wunderblog has now posted a list of all the hurricane records broken in 2005 hurricane season, which has defied “normal rules” and isn’t over yet… Epsilon was upgraded to hurricane status and favorable conditions for tropical storm formation may last into mid-December. So there could be a Zeta.

Since at least 1851, according to Jeff Masters Wunderblog, no tropical storm has come within 500 miles of the Canary Islands, until last Monday, when Delta knocked “God’s Finger” into the ocean – a historical landmark and major tourist attraction. And although hurricane season officially ended at midnight (Nov. 30th), Epsilon, which marks the first time on record that 3 tropical storms have formed in November, is expected to linger until tomorrow, December 2nd.

Global warming? Or flip flop, from inactive to active hurricane period? Or both? Or is this debate merely an artifact of the media’s obsession with finding a smoking gun – which makes a better story line, given Low Ambiguity Tolerance among consumers of news? And of presenting complex and multifaceted science and policy issues as a two sided debate.

[Addendum: or maybe it is the policy process itself that has a Low Ambiguity Tolerance - see also this post by Kevin Vranes.]

It is, or should by now be, common knowledge that one can’t link individual hurricane events to global warming, and that asking whether global warming caused Katrina is the wrong question. But that doesn’t mean it isn’t a contributing factor, or that there isn’t an link between global warming and an increase in the intensity of hurricanes. The record isn’t long enough to say anything conclusive about hurricane frequency. There have been plenty of articles and posts on this, but here is one more, by James Risbey, Karl Braganza and Thomas Homer-Dixon that provides a good summary of scientific evidence, from theory, models, and observations, all of which point to a link, and presents the context and nuance that are missing from most news accounts, but that are critical for understanding complex problems and their implications. In case you haven’t followed this one, more on this in RealClimate, in this Washington Post article, in this interview with Judith Curry, and in presentations made by Kevin Trenberth, Judith Curry, and Kerry Emanuel at the Environmental Seminar Series of the American Meteorological Association, which I attended but did not blog about at the time because Chris Mooney put up a good summary of it here. But will add that, in informal remarks afterwards, Judith Curry also raised the issue discussed here, that the media always makes scientists look more divided than they are, because they present issues as a polarized debate when the reality is, that climate researchers and hurricane forecasters just have different perspectives and are learning from each other – and could and should do more of that.

Still, it seems like every time a hurricane comes ashore, as we are all reminded of this likely connection, Roger Pielke Jr. is there to remind everyone that there is no evidence that additional hurricane intensity has contributed to the increase in damages, which depend on what lies in the hurricane’s path, and that reducing greenhouse gas emissions won’t prevent this. Fair enough. But it does not seem like a constructive way to frame the problem. As to whether current scientific understanding of global warming and hurricanes justifies policies to reduce greenhouse gas emissions, it depends… on values. It should also be common knowledge that life is uncertain, that science is no crystal ball, and that waiting for more data also has a cost. What we do know tells us that humans have increased the uncertainty of the climate itself even if we are uncertain by how much or what the impacts will be.

However, it would help if there were more clarity about what the benefits of reducing emissions are, and are not. And to also bring an equal amount of attention to the need for policies aimed at reducing vulnerability, and adapting to more rapid changes and greater variability in climate that are now unavoidable. I have not heard any claims that reducing emissions would significantly reduce the frequency and intensity of hurricanes over the forseeable future. The reason to reduce emissions is to stablilize atmospheric concentrations of greenhouse gasses at or below a level needed to prevent average global temperatures from rising to a level that would cause more catastrophic impacts, as opposed to just devastating ones. But long-term benefits are never quite as compelling as a hurricane headed for New Orleans, or even the reduction of snowfall, upon which water supplies depend in the western US, and which can be a matter of life an death to reindeer herds in the arctic, which is warming twice as fast as the rest of the planet, and those who depend on them, who are literally on the front lines.

Those who do not have children, or nieces and nephews, or some unreconstructed economist, might say something like “what has posterity done for me?” I’m not really in a philosophical mood this morning, but see this essay by Dmitri Podborits, where he talks about “deferring the recognition of the universe’s challenge until the crisis that is currently visible on the horizon becomes detectible through market and monetary mechanisms, signals from which in this particular peculiar civilization apparently take precedence over the other six senses” – the sixth being rational reasoning. I have nothing against economists who recognize the limits of their discipline but find economic anthropology to be more interesting and perhaps even useful for thinking about the long-term. Adopting an impersonal and delayed view of reciprocity, often found in traditional subsistence economies, we might think of leaving something for posterity as a way repay a debt to our ancestors, who developed the wits to survive an ice age. In Post-Normal Times, we will need those wits. When dealing with uncertainty, this broader concept of reciprocity and of value is even rational… I’ll elaborate on that when I’m in the mood for a diatribe. In the meantime, policies that reduce greenhouse gas emissions, such as reducing sprawl development patterns, and improving public transportation, can have many other environmental and social benefits – even if they don’t reduce the frequency and intensity of hurricanes. In New Orleans, improved public transportation would have reduced vulnerability to Katrina.