Bryan Caplan  

Learning from Lomborg

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Ayn Rand, Economic/Political G... Layard and Happiness...

There's a reason why Bjorn Lomborg has been rewarded for writing The Skeptical Environmentalist with a pie in the face. The book's good, very good - and that's bound to anger the touchy, gloomy Greens he's debunking.

The book has few big surprises for me - I've been reading the late great Julian Simon for years. (I never met him, though. Let that be a lesson to you to meet everyone you'd like to meet while there's still time). But few does not mean zero. Lomborg's most subjectively striking claims:

1. Trees don't on net produce oxygen.

In the 1970s we were told that rainforests were the lungs of the Earth... But this is a myth. True enough, plants produce oxygen by means of photosynthesis, but when they die and decompose, precisely the same amount of oxygen is consumed... Even if all plants, on land as well as at sea, were killed off and then decomposed, the process would consume less than 1 percent of the atmosphere's oxygen.

My 4th-grade teacher told me the "lungs of the Earth" story, and I've believed it during the subsequent quarter decade. But Lomborg's claim seems pretty cut and dried. Is he wrong?

2. Indoor air pollution kills about as many people as outdoor air pollution.

In part because "we spend by far most of our time indoors and because our homes have become more tightly sealed since the oil crisis because we insulate them better":

[I]n the U.S. indoor air pollution is estimated to cause between 85,000 and 150,000 deaths a year compared to between 65,000 and 200,000 deaths caused by outdoor air pollution.

This result is particularly interesting for economists because indoor air pollution is not a negative externality. The people who breathe the air pay for its quality. Reading this makes me want to open my windows more often. And maybe I should have installed a radon vent for my basement after all.

My big question: Is Lomborg's autobiography for real? Lomborg says he had no sympathy for Simon's views before he started this line of research:

"I'm an old left-wing Greenpeace member... Honestly, we expected to show that most of Simon's talk was simple, American right-wing propaganda."

I don't have any reason to doubt his story, except that I doubt all stories of this sort. But I would really like a neutral party to check it out.

Who cares? It goes to credibility. If a Danish statistician with strong Green leanings looked at the data and wrote this book, I'm going to get a lot more confident in my environmental optimism. Otherwise, I'll stay about where I started.



COMMENTS (14 to date)
Ronnie Horesh writes:

Lomborg's chapter on climate change is apparently discredited here (where it is also said that Greenpeace denies he was ever a significant member).

back40 writes:

"Lomborg's claim seems pretty cut and dried. Is he wrong?"

If not for photosynthesizing plants there would be almost no free oxygen on this planet. Prior to the evolution of cyanobacteria the atmosphere was less than 1% oxygen but now it is about 20%. No plants, no people. Oxygen is highly reactive - add a little heat and things go boom - and would soon all be locked up if not freed by plants.

Lomborg's claim doesn't seem to make any sense. It seems that he failed to consider oxygen chemistry. But it is also not true that all tree flesh, or other plant flesh, rots back into CO2. Some is sequestered in the soil as durable carbon compounds. One of the problems of agriculture is that soils are cultivated, plowed, and this exposes otherwise stable carbon compounds to atmosphere and causes large emissions of both CO2 and methane. And then there's fossil carbon, including even non-obvious forms such as the calcium carbonate secreted as exoskeleton by several life forms.

Both the carbon and oxygen cycles are more complicated than Lomborg suggests, and the metaphor of photosynthesizing plants as the planet's lungs isn't that bad if you squint a bit, reverse lungs perhaps since they emit oxygen.

Bob Knaus writes:

The carbon cycle is ill-understood at best. Here's a link to a NASA site with some nice grapics, and text saying that they really don't know what is happening to a lot of the human-emitted CO2.

Unlike the usual "hockey-stick" graph that accompanies global warming articles, this one shows a much longer term graph derived from Antarctic ice cores. The obvious conclusion from this graphic is that man has merely capped a huge natural spike in CO2 that accompanied the end of the last ice age.

Not to say that we shouldn't do something about cleaning up what mess we've made! But the forces of nature at work here are far larger than our puny efforts.

I can look out of my cockpit and see Bahamian islands now covered by trees that were either underwater or isolated beach dunes less than 5000 years ago. Global warming? You betcha. Good thing it has cooled down a bit since then, so that we have wonderful island paradises to play in.

Let's enjoy them while we can, eh?

Capt. Bob Knaus
S/V PELLUCID

Lawrance George Lux writes:

Lomborg and Simon both utilize short-term scenerios to assert environmental pollution efforts are overtouted and too expensive. Simon never accepted his lower resource-cost principle relied on the viability of substitutive technology, which Some see as reaching Cost-set limits of expansion. Lomborg is simply an idiot fulfilling a intelligent man's error. lgl

Jon writes:

Bjorn Lomborg may be almost right, but his point shows a remarkable capability of distorting evidence to fit his view point.

One of the key ways plant captured carbon gets converted back to CO2 is animal (yes, ours!) respiration. The bound carbon in our food ultimately originates from plants! Its conversion (with atmospheric removal in atmospheric O2) to CO2 is the carbon cycle.

Jon writes:

Simon makes the opposite mistake from his ditractors. Human ingenuity is not infinite; we just do not know its bounds. That does not mean they don't exist.

BTW, there is one commodity whose price has risen faster than inflation -- real property (land).

Mark Horn writes:

I don't know if human ingenuity is infinite or not. If it is finite, not knowing where the boundaries are doesn't tell me whether were 20% of the way through our ingenuity or 90%.

My conclusion: we simply don't know. Assuming that it's finite is at least as big an error as assuming that it's infinite. And it might even be a bigger error.

People have been predicting the end of human ingenuity for a very long time. My favorite prediction comes from Julius Frontinus who predicted in the first century A.D. that "Inventions reached their limit long ago, and I see no hope for further development." Consider also the wrong predictions over the last 30 years of the imminent end of Moore's law.

If I'm going to err in one direction or the other, history suggests that I err in the direction of optimism about human ingenuity.

George writes:

Cyanobacteria are not plants.

Eric Johnson writes:

I'd like to know how he comes up with 85,000 and 150,000 deaths yearly from indoor polutants. The sources I've looked at have radon killing 15k-21K/year and Environmental Tobacco Smoke killing between 38K and 53K. What other causes could explain the other 76,000 deaths (on the high end)?

You claim that indoor air pollution is not an externality. I believe that Environmental Tobacco Smoke would qualify as one.

dsquared writes:

True enough, plants produce oxygen by means of photosynthesis, but when they die and decompose, precisely the same amount of oxygen is consumed

This would imply that a growing plant population would be a net producer of oxygen while a decomposing one would be a net consumer. Since plants grow quickly, at the earth's surface but decompose slowly and partly underground or underwater I would guess that they would be net producers of oxygen.

In any case, it's clear that plants would in any sensible case be either net producers or net consumers; the "neutrality" result would be an oddball corner case that you would have to fine-tune the growth and decomposition rates to achieve. If Lomborg couldn't see this right off the bat I would worry about the rest of his analysis.

Furthermore, this bit is pretty darn silly:

Even if all plants, on land as well as at sea, were killed off and then decomposed, the process would consume less than 1 percent of the atmosphere's oxygen

This may be true. Similarly, if every automobile plant in the world was nuked, I would guess that this process would destroy less than 1% of the world's automobiles. However, I would also guess that it would cause more than a little disruption in the production of automobiles, and that someone who breathed automobiles would be more than one per cent worried.

Mark writes:

On the subject of Lomborg's autobiography, I remember reading an interview in The American Enterprise in which Lomborg said that his Greenpeace activism consisted solely of "going to a few meetings." As I recall, he also acknowledged that he wasn't really on the left politically, but more of a centrist.

As for the validity of the book, I can't say that I know for sure that he's wrong on every issue. However, I have seen several definitive rebuttals of his treatments of specific issues, such as Peter Gleick's refutation of his analysis of water issues, and two or three separate ones on his discussion of species extinction. I also found, when reading the book, that when he was writing about an issue which I know something about, that he repeatedly would distort the issue to present things in as optimistic a way as possible.

For example, when he describes trends in public health, he points sunnily to data showing that deaths from diseases like tuberculosis are far fewer than in the past, but says nothing about the present, growing problem of the emergence of antibiotic-resistance strains of TB, et. al., which threaten to reverse those gains. Anyone who is moderately informed on public health issues could have pointed this out to him.

Likewise, when he presents data on all sorts of global trends, such as poverty rates, he makes much of the fact that he is using "official" numbers. But he never addresses the fact that many "official" statistics, such as those of the government of China, are notoriously unreliable--something that he, as a stats professor, ought to be aware of. Instead, he repeatedly assumes that if a number is "official," it must be unquestionably accurate.

I have found so many issues on which Lomborg is unreliable that I have adopted the same approach to his claims that I take with other sources I have also found unreliable--never accept any claim he makes unless I can independently verify it from a reliable source. I encourage others to take the same approach to his book.

Jon writes:

Also the statement

Even if all plants, on land as well as at sea, were killed off and then decomposed, the process would consume less than 1 percent of the atmosphere's oxygen

confuses an accumulated amount with a flux. Even if true, it is thus highly misleading. The initial change in oxygen would be small, but as animals continued to breath and decompose, the oxygen would slowly get depleted, assuming there was some way to sustain animal life without plants in the food chain.

Jim Erlandson writes:

A recent article in New Scientist claims that

Hydroelectric dams produce significant amounts of carbon dioxide and methane, and in some cases produce more of these greenhouse gases than power plants running on fossil fuels.

This is because large amounts of carbon tied up in trees and other plants are released when the reservoir is initially flooded and the plants rot. Then after this first pulse of decay, plant matter settling on the reservoir's bottom decomposes without oxygen, resulting in a build-up of dissolved methane. This is released into the atmosphere when water passes through the dam's turbines.

Which again proves that the Firesign Theatre was right when they said, "Everything you know is wrong."

Guan Yang writes:

Bjørn Lomborg is not actually a statistician. His MA and PhD are in political science.

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