Eric Rasmusen’s Weblog

Has anyone pointed out that large landfills full of plastic bottles and disposable diapers are a solution to global warming?

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The sociology of global warming continues to puzzle me. Claims for it are wildly exaggerated. At the same time, however, I hardly ever see mentioned two of the strongest arguments on the pro-action side, to wit:

1. Temperature increases have been concentrated in the interiors of Asia and North America in winter. This is significant, because if increased carbon dioxide is the cause, warming would be strongest where there is the least water vapor– interior land masses with cold dry air. That’s a lot stronger evidence than just the correlation with increased CO2 levels. (Has anyone applied sophisticated time series techniques to that correlation, by the way? Maybe non-economists don’t know those techniques.)

2. There is some possibility of a catastrophic cycle of increased warming, turning the Earth into another Venus. Posner has emphasized this, I hear, in his book. That is much more serious than a few degrees of extra heat, even if less probable.

That these two things get so little play makes me wonder about the judgement of the pro-action people. But it means they may be even more correct than they think, too.

Brett Stephens has a good op-ed on how the behavior of prominent scientists in global warming makes the non-experts skeptical: (more…)

There is serious testing going on of dumping iron into the ocean to reduce carbon dioxide. See “Plan to Dump Iron in Ocean Criticized”, which also seems to me to imply that an important cause of global warming is a decline in plankton:

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I’m always frustrated by the difficulty of getting the basic models and facts of global warming. What happens to carbon dioxide in the ocean is important. Lots of carbon dioxide is dissolved in the ocean, and lots is taken up by ocean plants. The ocean is not saturated with carbone dioxide, unlike nitrogen and oxygen. So, will the ocean soak up some large fraction of the carbon dioxide man is putting into the atmosphere?

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I wonder if the CO2 scientists have accounted for the sequestering of carbon that results from increased crop yields. The natural limit on vegetation is apparently fertilizer, not carbon dioxide. Thus, with more fertilizer we have increased the amount of vegetation. We are eating more, too, but at any one time there is more carbon locked up in crops than there would have been 100 years ago. Trees have their own pattern, of course, and are better at sequestering carbon since they “waste” it in nonliving parts of the trunk.

Also, what would be the effect of the warming of Siberia and Canada on plant life? There would be a longer growing season perhaps– it might depend on sunshine instead of heat— but there might be fewer trees and more bushes.

Carbon Dioxide Information Analysis Center Frequently Asked Global Change Questions says that burning a gallon of gasoline produces 19.6 pounds of carbon dioxide, 8.8 kilograms, and a person’s breathing produces about 1 kilogram per day(though it depends on how hard he is breathing). Suppose I drive about 20 miles per day, using one gallon of gasoline. Then every day my car generates 8.8 kilograms of carbon dioxide and my breathing generates 1 kilogram. So driving does contribute more.[I misread the number as 1kg/HOUR in the draft of the post earlier today]

The CDIAC site says that my breathing is not a net contributor to carbon dioxide because I do not emit more than I eat in the form of plant and animal food, and those plants and animals’ carbon came from the atmosphere ultimately. That is wrong. My breathing does add carbon dioxide; it’s just that my other activities ultimately subtract the same amount. If, however, I stopped eating, we could take the food I eat and bury it and that would reduce greenhouse gases far more than if I had just stopped driving.

Later that day: Come to think of it, let’s check the numbers. First, gasoline. One gallon is 8 pints, which is 8 pounds of water. Water is H20, Oxygen basically. Gasoline is various C-H compounds, Carbon basically, which is lighter than oxygen (hence oil floats on water). Thus,one gallon has, say, 6 pounds of carbon, which combines with 2 parts Oxygen to make CO2— 6+8+8=22 pounds, pretty close to 19.6.

Now check breathing. 1 kilogram of C02 per day is about 2 pounds which is about .8 pounds of carbon per day. I have to get all that carbon by eating, and much of my food is water, not carbon. I suppose I eat about 4 pounds of food per day, of which 1 pound is carbon, so that matches up pretty well.

I wonder if a carbon tax might not be a good idea even if it has absolutely no effect on global warming. The reason is that it is a flat tax rather than a progressive tax.

If taxes simply increase, that is of course more distortionary than our present system, but presumably if we imposed a carbon tax we would reduce the income tax to keep revenue constant. Then the two questions are (a) how distortionary is a carbon tax compared to a tax on labor, rents, and capital income, and (b) if the carbon tax is more distortionary in general, does its lack of progressivity and loopholes nonetheless make it less distortionary?

Of course, it could be that carbon is a luxury good, in which case a carbon tax is progressive in effect even if it is flat as applied. Or, it could be regressive in effect, which would increase its efficiency even more by reducing the tax effect on the marginal dollar.

Pete Dupont has an excellent op-ed in the WSJ on global warming, with a coda about DDT and malaria.

Sunspot activity has reached a thousand-year high, according to European astronomy institutions. Solar radiation is reducing Mars’s southern icecap, which has been shrinking for three summers despite the absence of SUVS and coal-fired electrical plants anywhere on the Red Planet. Back on Earth, a NASA study reports that solar radiation has increased in each of the past two decades, and environmental scholar Bjorn Lomborg, citing a 1997 atmosphere-ocean general circulation model, observes that “the increase in direct solar irradiation over the past 30 years is responsible for about 40 percent of the observed global warming.”

… Half of the past century’s warming occurred before 1940, when the human population and its industrial base were far smaller than now.

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There’s a very nice NASA-GISS site where you can click on a map of the United States to get monthly weather station temperatures since 1880. This will be useful to check out the facts when people say in conversation, “Oh, global warming has made it so much warmer this past few years around here.” Here’s some of the yearly averages for Bloomington, Indiana.

1980 11.71
1981 11.88
1982 11.08
1983 13.19
1984 11.3
1985 12.73
1986 12.39
1987 12.89
1988 12.11
1989 11.83
1990 12.32
1991 13.38
1992 12.18
1993 11.68
1994 11.97
1995 12.43
1996 10.91
1997 10.9
1998 13.64
1999 13.17
2000 12.06
2001 11.74
2002 12.76
2003 11.22
2004 12.26
2005 12.58

This data on monthly deviations from 1961-1990 monthly temperatures may be a bit hard to read, but it is interesting. It shows that the past decade has been warmer than 1961-1990, but it isn’t clear that the world is getting warmer in the 21st century. The source is the IPCC, a group which supports efforts to stop global warming.

The yearly averages are:
Year Average
1996 0.205
1997 0.462
1998 0.817
1999 0.487
2000 0.361
2001 0.553
2002 0.661
2003 0.641
2004 0.612
2005 0.745
2006 0.658

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Tyler Cowen has a good summary of his views on the social discount rate, in a post relating to Stern’s assumption of it being zero in global warming calculations: (more…)

A new thought on global warming: even if there is a 10% chance of bad things happening because of global warming, we should have a plan to deal with it. And even if there is a 90% chance, we should have a plan that is reversible, not causing permanent harm.

I think this lends argument to plans such as getting ready to put soot into the atmosphere to make it more opaque— but for waiting to do so until the bad effects are noticeable. If we were to be restricted to CO2-emission-reducing policies, it makes for a complicated and interesting tradeoff between restricting now, possibly uselessly, and restricting later, when adjustment costs are higher.

A WSJ article by global warming skeptic Richard Lindzen has some useful stylized facts.

Most of the climate community has agreed since 1988 that global mean temperatures have increased on the order of one degree Fahrenheit over the past century, having risen significantly from about 1919 to 1940, decreased between 1940 and the early ’70s, increased again until the ’90s, and remaining essentially flat since 1998.

There is also little disagreement that levels of carbon dioxide in the atmosphere have risen from about 280 parts per million by volume in the 19th century to about 387 ppmv today. Finally, there has been no question whatever that carbon dioxide is an infrared absorber (i.e., a greenhouse gas–albeit a minor one), and its increase should theoretically contribute to warming. Indeed, if all else were kept equal, the increase in carbon dioxide should have led to somewhat more warming than has been observed, assuming that the small observed increase was in fact due to increasing carbon dioxide rather than a natural fluctuation in the climate system.

I find the global warming debate very hard to follow. There is lots of garbage published, and the respectable writers are not all that trustworthy, from what I can see. It is hard even to figure out the basic facts, and the models seem to be highly speculative and presented with too much confidence. I’m reminded of medical studies, with their dubious statistics and careless disregard of alternative causes.

One thing I wonder about is the actual pattern of temperature change over time. I know it’s not been a uniform increase in temperature over the 20th century– the temperature actually fell for 20 or so years in mid-century. That’s OK, if what we’re interested in is long-term trends, though it should remind us that the year-to-year variation in average temperature is greater than the century-to-century variation. But what I’d also like to pin down is (1) How does the temperature increase vary by continent and ocean? and (2) How much of the increase is in the summer and how much in the winter?

What I’ve heard is that global temperatures are not increasing. Rather, the average global temperature is increasing, because temperatures in some places and during some seasons are increasing. To wit, winter temperatures in central North America and Asia are increasing. I’d like to know if this is true, and temperatures at other times of year and in other places are not.

This is a big deal. When we worry about global warming, most of us are worrying about increases in summer temperatures, especially in the tropics, where life could become unbearable, or in the polar regions, where the ice would melt. We don’t worry about North Dakota winters having fewer below-zero days.

A Cato article shows the pattern of warming. Figure 48.1 above shows that the big increases in temperature have been in the Great Plains, Finland, and Siberia. Figure 48.3 shows that in the US since the 60′s it has been in the winter. It looks like the per-decade farenheit temperature increase by three-month group has been : JFM:.55, AMJ +.12, JAS +.08, OND -.11. Farneheit per decade. Extrapolating, in 50 years the US temperature would be about 3 degrees warmer in the winter and half a degree in the summer.