Everyone in the room agrees that the earth has been getting warmer and they generally suspect that human activity has something to do with it. But they also agree that the standard global-warming rhetoric in the media and political circles is oversimplified and exaggerated. Too many accounts, Myhrvold says, suffer from “people who get on their high horse and say that that our species will be exterminated.”
Does he believe this?
“Probably not.”
When An Inconvenient Truth is mentioned, the table erupts in a sea of groans. The film’s purpose, Myhrvold believes, was “to scare the crap out of people.” Although Al Gore “isn’t technically lying,” he says, some of the nightmare scenarios Gore describes — the state of Florida disappearing under rising seas, for instance — “don’t have any basis in physical reality in any reasonable time frame. No climate model shows them happening.”
But the scientific community is also at fault.
The current generation of climate-prediction models are, as Lowell Wood puts it, “enormously crude.” Wood is a heavyset and spectacularly talkative astrophysicist in his sixties who calls to mind a sane Ignatius P. Reilly. Long ago, Wood was Myhrvold’s academic mentor.
(Wood himself was a protégé of the physicist Edward Teller.) Myhrvold thinks Wood is one the smartest men in the universe. Off the top of his head, Wood seems to know quite a bit about practically anything: the melt rate of the Greenland ice core (80 cubic kilometers per year); the percentage of unsanctioned Chinese power plants that went online in the previous year (about 20 percent); the number of times that metastatic cancer cells travel through the bloodstream before they land (“as many as a million”).
Wood has achieved a great deal in science, on behalf of universities, private firms, and the U.S. government. It was Wood who dreamed up IV’s mosquito laser assassination system—which, if it seems vaguely familiar, is because Wood also worked on the “Star Wars” missile-defense system at the Lawrence Livermore National Laboratory, from which he recently retired. (From fighting Soviet nukes to malarial mosquitoes: talk about a peace dividend!)
Today, at the IV think session, Wood is wearing a rainbow tie-dyed short-sleeve dress shirt with a matching necktie.
“The climate models are crude in space and they’re crude in time,” he continues. “So there’s an enormous amount of natural phenomena they can’t model. They can’t do even giant storms like hurricanes.”
There are several reasons for this, Myhrvold explains. Today’s models use a grid of cells to map the earth, and those grids are too large to allow for the modeling of actual weather. Smaller and more accurate grids would require better modeling software, which would require more computing power. “We’re trying to predict climate change twenty to thirty years from now,” he says, “but it will take us almost the same amount of time for the computer industry to give us fast enough computers to do the job.”
That said, most current climate models tend to produce similar predictions. This might lead one to reasonably conclude that climate scientists have a pretty good handle on the future.
Not so, says Wood.
“Everybody turns their knobs” — that is, adjusts the control parameters and coefficients of their models — “so they aren’t the outlier, because the outlying model is going to have difficulty getting funded.” In other words, the economic reality of research funding, rather than a disinterested and uncoordinated scientific consensus, leads the models to approximately match one another.
It isn’t that current climate models should be ignored, Wood says — but, when considering the fate of the planet, one should properly appreciate their limited nature.
As Wood, Myhrvold, and the other scientists discuss the various conventional wisdoms surrounding global warming, few, if any, survive unscathed.
The emphasis on carbon dioxide? “Misplaced,” says Wood.
Why?
“Because carbon dioxide is not the major greenhouse gas. The major greenhouse gas is water vapor.” But current climate models “do not know how to handle water vapor and various types of clouds. That is the elephant in the corner of this room. I hope we’ll have good numbers on water vapor by 2020 or thereabouts.”
Myhrvold cites a recent paper asserting that
carbon dioxide may have had little to do with recent warming. Instead, all the heavy-particulate pollution we generated in earlier decades seems to have cooled the atmosphere by dimming the sun. That was the global cooling that caught scientists’ attention in the 1970s. The trend began to reverse when we started cleaning up our air.
“So most of the warming seen over the past few decades,” Myhrvold says, “might actually be due to good environmental stewardship!”
Not so many years ago, schoolchildren were taught that carbon dioxide is the naturally occurring lifeblood of plants, just as oxygen is ours. Today, children are more likely to think of carbon dioxide as a poison. That’s because the amount of carbon dioxide in the atmosphere has increased substantially over the past one hundred years, from about 280 parts per million to 380.
But what people don’t know, the IV scientists say, is that the carbon dioxide level some 80 million years ago—back when our mammalian ancestors were evolving — was at least 1,000 parts per million. In fact, that is the concentration of carbon dioxide you regularly breathe if you work in a new energy-efficient office building, for that is the level established by the engineering group that sets standards for heating and ventilation systems.
So not only is carbon dioxide plainly not poisonous, but changes in carbon-dioxide levels don’t necessarily mirror human activity. Nor does atmospheric carbon dioxide necessarily warm the earth:
ice-cap evidence shows that over the past several hundred thousand years, carbon dioxide levels have risen after a rise in temperature, not the other way around.
LEVITT, S. D.; DUBNER, S. J. Superfreakonomics. New York: Harper Collins, 2009
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