Smoke is our friend, global-warming-wise. It stops solar energy from reaching the surface, and therefore helps to reduce global warming. U.S. atmospheric temperatures actually fell during the 30-year period from about 1945 to 1975, even though manmade CO2 was making CO2 concentrations increase steadily throughout this same period. One possible explanation is the dirty coal we burned then, that it introduced sufficient solar-blocking sulfur into the atmosphere to overcome the additional CO2's increase of the greenhouse effect. Maybe it sounds crazy today, but if planetary survival depends on bringing temperatures down, maybe someday we'll be pumping sulfur into the air on purpose.
Anyway, it's the greenhouse gases that are the villains in global warming. Not smoke or sulfur or acid rain, not the destruction of the ozone layer, not the unburned hydrocarbons (HC) or oxides of nitrogen (NOx) or carbon monoxide (CO) that automotive emissions regulations were originally enacted to bring under control.
The greenhouse effect arises from the interaction of earth's atmosphere with solar energy. Solar energy arrives at earth's atmosphere in relatively short wavelengths. The greenhouse gases do not block this incoming solar energy. So it penetrates the atmosphere and warms whatever it hits -- e.g., a land mass, or an ocean. This heat energy then tries to radiate back out toward outer space, in the form of longwave ("LW") infrared radiation. This is the energy that the greenhouse gases absorb, which causes them to warm, which causes the greenhouse effect.
The greenhouse effect is our friend. If the energy that the greenhouse gases block were not blocked and were instead allowed to escape into outer space, earth's mean atmospheric temperature would be colder by 33 degrees *centigrade*. So we like the greenhouse effect, up to a point. It's global warming -- a greenhouse system that is taking in more solar energy than it can radiate back out in the form of LW radiation -- which is the problem.
So what are the main causes of the greenhouse effect, i.e., the absorbtion of LW radiation? In first place is water vapor -- H2O in a gaseous state. Second are clouds -- liquid H2O suspended in the air. CO2 is a very distant third. The main reason for the primacy of water vapor is that it can make up as much as 4% of the atmosphere, by volume. By comparison, CO2 occupies only about 0.035%.
According to this *pro*-regulation website --
Well fine, you might say, get rid of 9% to 26% of the greenhouse effect, and the equilibrium will settle into a nice, comfortable, cooler norm. The problem is, that we can't "get rid" of the CO2. It takes, on average, 100 years for a molecule of CO2 to get captured by some plant or another and turned into sugar and oxygen. Not only can we not get rid of the CO2 that's already up there; we can't even stop the rate of increase, unless we pretty much stop burning hydrocarbons altogether.
How much is that rate of increase? According to a Patrick Bedard editorial in the September 2006 Car and Driver, after 200 years of industrial revolution, the manmade proportion of CO2 is only 3.23% of the total volume of CO2 out there. How much is added each year, I don't know.
So there it is. 100% of the CO2 causes between 9% and 26% of the greenhouse effect. But only 3.23% of the CO2 is manmade. In a way, then, only 0.29% to 0.84% (0.0323 x 9, 0.0323 x 26) of the greenhouse effect is manmade. Plus, what's done is done; we can't do anything about that 3.23% that's already up there. All we can do is stop adding more. The magnitude of what we can realistically stop adding -- a 25% cut in 14 years, as proposed by the soon-to-be-signed California law?
-- sounds so minimal as to sound not worth doing; not worth doing, anyway, if the costs are disproportionate to the benefits.
That, basically, is my question with respect to the regulation of manmade greenhouse gases. What are the benefits of this kind of regulation? What are the costs? DOES ANYBODY KNOW?
Another fun fact to know and tell about global warming: Take two cars, one with the full set of modern emissions controls, and another from
1965 or earlier, with no emissions controls at all. Assume that both cars return 21 mpg (which, BTW, is the current fleet average for 2007 cars; not trucks, SUVs, *and* cars, just cars). Which of these two cars is producing more CO2?That's right, the 1965 HC, CO, NOx emissions gorilla is the greenhouse gas minimizer. That's because the fuel efficiency of the modern EFI engine, combined with a catalytic converter, transforms nearly every atom of carbon that goes into the fuel tank as gasoline (C5H12, C6H14, C7H16, C8H18, C9H20, C10H22, C11H24, C12H26) into a molecule of CO2 . The *unburned* hydrocarbons ("HC") that emissions regulations were originally enacted to eliminate go out the tailpipe of the uncontrolled emissions gorilla with their carbon atoms still bonded to other carbon atoms and to protons (H+ ions).
I doubt if billions of tons of unburned HC being discharged into the atmosphere would have a favorable effect on global warming -- HC is not included in any list of greenhouse gases that I have seen, but in combination with NOx and sunlight it creates O3 (ozone) which *is* a greenhouse gas -- but it's kind of ironic that the main raison d'etre of the catalytic converter is to turn HC into CO2, the Bin Laden of greenhouse gases. I wonder if Bill Lockyer will sue the automakers for putting catalytic converters on their cars, since they would produce far less CO2 without them.
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