Viewpoint

Don't blame global warming

We're heading into the heart of hurricane season, and any day now, a storm will barrel toward the United States, inspiring all the TV weather reporters to find a beach where they can lash themselves to a palm tree.

We can be certain of two things: First, we'll be told that the wind is blowing very hard and the surf is up. Second, some expert will tell us that this storm might be a harbinger of global warming.

Somewhere along the line, global warming became the explanation for everything. Right-thinking people are not supposed to discuss any meteorological or geophysical event – a hurricane, a wildfire, a heat wave, a drought, a flood, a blizzard, a tornado, a lightning strike, an unfamiliar breeze, a strange tingling on the neck – without immediately invoking the climate crisis. It causes earthquakes, plagues and backyard gardening disappointments. Weird fungus on your tomato plants? Classic sign of global warming.

Uncertainty is inherent

You're permitted to note that no single weather calamity can be ascribed with absolute certainty to what humans are doing to the atmosphere. But some people are impatient with even a token amount of equivocation. A science writer for Newsweek recently declared that this year's floods in the Midwest were the result of climate change, and in the process, she derided the wishy-washy climatologists who couldn't quite bring themselves to reach that conclusion (they “trip over themselves to absolve global warming”).

Well, gosh. Equivocation isn't a sign of cognitive weakness. Uncertainty is intrinsic to the scientific process, and sometimes you have to have the courage to stand up and say, “Maybe.”

Seems to me that it's impossible to prove a causal connection between climate and weather – they're just two different things. “Weather alarmism” gives ammunition to global-warming deniers. They're happy to fight on that turf, since they can say that a year with relatively few hurricanes (or a cold snap when you don't expect it) proves that global warming is a myth.

There's an ancillary issue here: Global warming threatens to suck all the oxygen out of any discussion of the environment. We wind up giving too little attention to habitat destruction, overfishing and so on.

You don't need a climate model to detect that big oil spill in the Mississippi. That “dead zone” in the Gulf of Mexico – an oxygen-starved region the size of Massachusetts – isn't caused by global warming, but by all that fertilizer spread on Midwest cornfields.

Some folks may get the notion that the planet will be safe if we all just start driving hybrids. But even if we cured ourselves of our addiction to fossil fuels and stabilized the planet's climate, we'd still have an environmental crisis on our hands. Our fundamental problem is that – now it's my chance to sound hysterical – humans are a species out of control. We've been hell-bent on wrecking our environment pretty much since the day we figured out how to make fire.

“One can only speak rationally about odds,” Kerry Emanuel, a climatologist at the Massachusetts Institute of Technology who has studied hurricanes and climate change, told me. “Global warming increases the probabilities of floods and strong hurricanes, and that is all that you can say.”

Emanuel's research shows that in the past 25 years, there's been an uptick in the number of strong storms, though not necessarily in the number of hurricanes overall. Climate models show that a 1-degree Celsius rise in sea-surface temperatures should intensify top winds by about 5 percent, which corresponds to a 15 percent increase in destructive power. The tropical Atlantic sea surface has warmed by 0.6 degrees Celsius in the past half-century.

At my request, Emanuel ran a computer program to see how much extra energy Hurricane Katrina had because of increases in sea-surface temperature. His conclusion: Katrina's winds were about 2 percent stronger in the Gulf, and not significantly stronger at landfall.

Maybe climate change was a factor in generating such a storm, or in the amount of moisture it carried, but the catastrophe that Katrina caused in New Orleans can more plausibly be attributed to civil engineers who built inadequate levees, city planning that let neighborhoods develop below sea level and Bush administration officials who didn't do such a heckuva job.

Basic problem is us

The thing that gets you in the end is rarely the thing you're paying attention to.

The basic problem is that there are so many of us now. Four centuries ago, there were about 500 million people on Earth. Today there are that many, plus 6 billion. We're rapidly heading toward 9 billion. Conservatives say that we just need to focus on maintaining free markets and let everything sort itself out through the miracle of the invisible hand. But the political tide is turning against unfettered free markets and toward greater regulation. Climate-change policy is part of that: Somehow we've got to embed environmental effects into the cost of energy sources, consumer goods and so on. The market approach by itself has let us down.

Last week, we saw reports of more wildfires in California. Sure as night follows day, people will lay some of the blame on climate change. But there's also the minor matter of people building homes in wildfire-susceptible forests, overgrown with vegetation due to decades of fire suppression.

The message that needs to be sent to these people is: “Your problem is not global warming. Your problem is that you're nuts.”

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