This is a pretty good review of carbon dioxide and its role in the climate of Earth. Now that the political version of climate science has been exposed as largely bogus, a lot of the contradictory voices are swiftly getting published and gaining an audience.
A lot of this we already know but the clear take-home message is that the geological record supports CO2 levels at 1000 ppm as likely the best overall level for supporting our ecosystem. It may turn out that the ongoing recovery from the ice age is actually promoting a return to that effective level. We have many centuries to go yet.
What is been buried is the curious hypothesis that rising CO2 is driving global warming. It simply is not. There might be a contribution, but we cannot even show that. Right now the folks here have satisfied themselves that such contribution is clearly negligible.
The climate certainly varies and often surprises. We presently have been riding through a peak cosmic ray flux which argued this early fall for a miserable winter. Thus we could predict a miserable winter. So far we have been having a miserable winter that certainly is not disappointing our predictions.
Steven D.Levittand Stephen J. Dubner: The green gadflys
Posted:January 07, 2010, 10:30 AM by NP Editor
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 100 years, from about 280 parts per million to 380.
But what people don’t know, say the scientists at Intellectual Ventures labs in Bellevue, Wash., 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.
Meet Ken Caldeira, a soft-spoken man with a boyish face and a halo of curly hair. He runs an ecology lab at Stanford University
If you met Caldeira at a party, you would likely place him in the fervent-environmentalist camp himself. He was a philosophy major in college, for goodness’ sake, and his very name — a variant of caldera, the crater-like rim of a volcano— aligns him with the natural world. In his youth (he is 53 now), he was a hard-charging environmental activist and all-around peacenik.
Caldeira is thoroughly convinced that human activity is responsible for some global warming and is pessimistic about how future climate will affect humankind. He believes that “we are being incredibly foolish emitting carbon dioxide” as we currently do.
Yet his research tells him that carbon dioxide is not the right villain in this fight. For starters, as greenhouse gases go, it’s not particularly efficient. “A doubling of carbon dioxide traps less than 2% of the outgoing radiation emitted by the earth,” he says. Furthermore, atmospheric carbon dioxide is governed by the law of diminishing returns: Each gigaton added to the air has less radiative impact than the previous one.
Caldeira mentions a study he undertook that considered the impact of higher carbon dioxide levels on plant life. While plants get their water from the soil, they get their food — carbon dioxide, that is — from the air. An increase in carbon dioxide means that plants require less water to grow.
Caldeira’s study showed that doubling the amount of carbon dioxide while holding steady all other inputs— water, nutrients and so forth— yields a 70% increase in plant growth, an obvious boon to agricultural productivity.
“That’s why most commercial hydroponic green houses have supplemental carbon dioxide,” a colleague says. “And they typically run at 1,400 parts per million.”
“Twenty thousand years ago,” Caldeira says, “carbon dioxide levels were lower, sea level was lower — and trees were in a near state of asphyxiation for lack of carbon dioxide. There’s nothing special about today’s carbon dioxide level, or today’s sea level, or today’s temperature. What damages us are rapid rates of change. Overall, more carbon dioxide is probably a good thing for the biosphere — it’s just that it’s increasing too fast.”
The gentlemen of Intellectual Ventures abound with further examples of global warming memes that are all wrong.
Rising sea levels, for instance, “aren’t being driven primarily by glaciers melting,” Lowell
Sea levels are rising, Wood says — and have been for roughly 12,000 years, since the end of the last ice age. The oceans are about 425 feet higher today, but the bulk of that rise occurred in the first thousand years. In the past century, the seas have risen less than eight inches.
As to the future: Rather than the catastrophic 30-foot rise some people have predicted over the next century — goodbye, Florida
Caldeira, with something of a pained look on his face, mentions a most surprising environmental scourge: trees. Yes, trees. As much as Caldeira personally lives the green life — his Stanford office is cooled by a misting water chamber rather than air conditioning — his research has found that planting trees in certain locations actually exacerbates warming because comparatively dark leaves absorb more incoming sunlight than, say, grassy plains, sandy deserts or snow-covered expanses.
Then there’s this little-discussed fact about global warming: While the drumbeat of doom has grown louder over the past several years, the average global temperature during that time has in fact decreased.
In the darkened conference room, Intellectual Ventures co-founder Nathan Myhrvold cues up an overhead slide that summarizes IV’s views of the current slate of proposed global warming solutions. The slide says:
- Too little
- Too late
- Too optimistic
Too little means that typical conservation efforts simply won’t make much of a difference. “If you believe there’s a problem worth solving,” Myhrvold says, “then these solutions won’t be enough to solve it. Wind power and most other alternative energy things are cute, but they don’t scale to a sufficient degree. At this point, wind farms are a government subsidy scheme, fundamentally.”
What about the beloved Prius and other low-emission vehicles? “They’re great,” he says, “except that transportation is just not that big of a sector.”
Also, coal is so cheap that trying to generate electricity without it would be economic suicide, especially for developing countries. Myhrvold argues that cap-and-trade agreements, whereby coal emissions are limited by quota and cost, can’t help much, in part because it is already …
Too late. The half-life of atmospheric carbon dioxide is roughly one hundred years, and some of it remains in the atmosphere for thousands of years. So even if humankind immediately stopped burning all fossil fuel, the existing carbon dioxide would remain in the atmosphere for several generations. Pretend the United States (and perhaps Europe ) miraculously converted overnight and became zero-carbon societies. Then pretend they persuaded China (and perhaps India
Too optimistic. “A lot of the things that people say would be a good thing probably aren’t,” Myhrvold says. As an example, he points to solar power. “The problem with solar cells is that they’re black, because they are designed to absorb light from the sun. But only about 12% gets turned into electricity, and the rest is reradiated as heat — which contributes to global warming.”
Although a widespread conversion to solar power might seem appealing, the reality is tricky. The energy consumed by building the thousands of new solar plants necessary to replace coal-burning and other power plants would create a huge long-term “warming debt,” as Myhrvold calls it. “Eventually, we’d have a great carbon-free energy infrastructure but only after making emissions and global warming worse every year until we’re done building out the solar plants, which could take 30 to 50 years.”
FromSuperFreakonomicsby Steven D.Levittand Stephen J. Dubner. Copyright © 2009 by Steven D.Levittand Stephen J. Dubner. Published with arrangement by HarperCollinsCanada
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