completeconfusion

This is an excerpt from a much longer article on Occam's Razor, whether it's still useful, and it's frequent failures during the history of science, at http://logictutorial.com/occam.html. In that article I discuss how Occam's Razor helped us to overlook Global Warming for so long, and then for completeness, go on to discuss a very recent new theory of Global Warming, what I'm dubbing the “Silver Cloud Theory”:

Excerpt:
It is not impossible that even in this last case that Occam's Razor will change the direction it's pointing in at least one more time. Surprising changes to the available data on temperature are certainly very unlikely, and a new hypothesis that fits the data better may seem unimaginable. However Vladimir Shaidurov has had sufficient imagination to throw one more hypothesis into the mix just recently. His interesting new paper relies only on accepted temperature data. A good jounalistic description of the theory can be found at [http://news.mongabay.com/2006/0313-vapor.html] and the more daunting original paper is at [http://arxiv.org/PS_cache/physics/pdf/0510/0510042.pdf]. This data shows average temperatures around the earth trending sharply upward only after the first decade of last century. Atmospheric water vapor is the most important greenhouse gas (not CO2) [1], but Shaidurov also points to the cooling effect of repeatedly crystallizing water vapor in the middle part of the mesosphere forming what are known as “silver clouds” more than 50km above the earth. These clouds reflect some sunlight back into space before it can reach earth. He hypothesizes that a large amount of water vapor was removed from this part of the upper atmosphere by the spectacular, 15 megaton explosion of the Tungus meteorite 10 above Siberia in 1908 “stirring the atmosphere” and heating it, and that this “restructuring” initiated the current process of global warming by thinning the layer of “silver clouds”. [2]

While the Tungus meteorite itself doesn't constitute a novel entity, of course; any large and self-sustaining effect on world temperature from such an event would be new to science. So that counts as a novel entity. The “silver clouds” are not new entities, but he may credit them with a stronger cooling effect than previous estimates, and his hypothesis does posit that they were more extensive before 1908 than today. For good measure Shaidurov also introduces another entity into his explanation (which in fairness may actually be necessary for any explanation that fits the available data [http://www.grida.no/climate/ipcc_tar/slides/large/05.16.jpg]) – namely a strong cooling countertrend from the end of World War II through the late Nineteen Seventies from dust and water vapor kicked up into the high atmosphere by above-ground nuclear testing. [3] The strength of that cooling trend would be at least partly due to his posited strong cooling effect from silver clouds: therefore, although it may seem confusing to say so, it would also be a bit of downstream complexity that actually confirms his theory, if this effect of nuclear testing were shown to be true.

In exchange for these two or three new entities however, he has given us an hypothesis fits the temperature data remarkably well and in so doing explains why the earth actually cooled for nearly a century after the Industrialization Revolution (continued a long-standing trend), according to the accepted data. As a bonus, (this is my addition and Shaidurov is not responsible for any error here) his hypothesis then also explains the obvious earlier, and much longer downward trend to boot. Connecting the dots, such gradual cooling would then be the general case historically, in between random collisions with large light meteorites. In other words, the earth was still cooling from the effects of a previous such collision when the Tungus meteorite hit. (It's estimated that similar explosions may happen as often as every couple of centuries - generally over water, unobserved.[http://www.psi.edu/projects/siberia/siberia.html])

Fairness insists I also list other evidence that's downstream of his theory, if it's true – but these points don't necessarily go unexplained by the industrial theory of global warming either.

1. The “silver cloud” hypothesis is also consistent with data that show that the amount of sunlight reaching the surface of the earth is actually gradually declining recently. This would be consistent with the very gradual restoration of “normal” water vapor levels in the mesosphere after a collision.

2. Latest versions of the standard theory show that the temperature rise before 1940 cannot be attributed to the smaller amount of CO2 emitted up to that time. The “silver cloud” or meteorite hypothesis explains this earlier rise, and the fact that the slope of that earlier rise (1910 to 1945) is pretty much the same as the current rise, despite the fact that emissions of CO2, methane, etc., have become far greater.

3. It may explain why the current rise is seemingly steady, not clearly accelerating, from the late 1970s to the present, although industrial emissions have increased. (Estimates of the rate of increase have risen recently as it has become clearer that warming wasn't evident from 1945 to 1980, there is no obvious curve or parabolic rise in recent decades. However, expected yearly variations in temperature within this short period obscure the matter.

4. It explains why ice cores show that in the distant past, periods of warming began before carbon dioxide levels rose, despite the fact that the standard theory supposes that CO2 is what drives significant climate change, in pre-history, and today.

In contrast, while the rise in global temperature over the last century has three stages: an early rise from 1910-1945, a plateau from 1945 to the late 1970s, and a rise since. All three components are quite unlike what we see in the several previous centuries, namely a steady fall in average temperatures. The standard theory can only explain the latest stage, since 1980. For it, the earlier rise, and the plateau, are extra, unexplained entities, as is the earlier gentle downward slope in temperature. Not exactly ideal.

Of course, that his new hypothesis fits the most obvious chunk of data we have very well doesn't make Shaidurov right, and that it also has explanations for other phenomenon doesn't prove it correct, either. I have no expertise in the area with which to render a any judgement with the net result that I'm still scared of industrialization but am also more frightened of meteorites than I was before. The precautionary principle suggest to me that we should be very careful of abandoning the standard theory prematurely.

He does suggest an experiment that would also be a cure for global warming if his hypothesis is true: rocketing payloads of hydrogen up to the mesosphere to replace the missing water vapor that will then form more “silver clouds”. If part of such a test is conducted and shows a sufficiently strong effect, or if other tests can be devised that would be decisive, then perhaps with the help of that additional data, Occam's Razor will swing 'round once again and declare that the effects of industrialization aren't causing global warming. Perhaps.

I hope, given the previously cited arguments and examples, that it goes without saying that we shouldn't allow self-satisfaction, or any conviction that Occam's Razor still most clearly supports the Industrialization Theory of Global Warming, to forestall us from gathering more data relevant to Shaidurov's Hypothesis. At worst we would learn more about a part of the atmosphere now sometimes referred to as the ignorosphere, since we know so little about it. But in the meanwhile I also hope that mere prudence, as well as the separate peril of ocean acidification by excess CO2, will motivate us to reduce greenhouse gas emissions as quickly and energetically as is possible.

Before we leave the topic of the earth's environment, one more imaginable consequence of Shaidurov's Hypothesis (the “Silver Cloud Theory of Global Warming”?) deserves to be raised. It suggests the distressing possibility that a too=quick resort to Occam's Razor might all too easily have produced vastly accelerating global warming by now. (Again this is another addition by myself, and Shaidurov is not responsible for any errors here, either.) For Occam's Razor then suggested that the mesosphere would not be dramatically more vulnerable to a nuclear explosion than any other part of the atmosphere. No-one then had any reason to suppose such a complexity or extra entity/vulnerability. Yet had that assumption, directly attributable to Occam's Razor, ever been used to help justify the test of a large nuclear bomb at very high altitude, we might be in the midst of a population crash now, if the “silver cloud” theory is right.

Such a test wasn't entirely unlikely, either. A live test of the Soviet Antiballistic Missle system, which employed nuclear bombs to detonate incoming nuclear warheads high up in the atmosphere, might have sufficed to for a doomsday scenario. The largest bomb ever tested, Tsar Bomba, in 1961; was several times as large as the Tungus event. It was dropped at low altitude but the mushroom cloud reached 18km. Typical nuclear bombs are more like 1.5 megatons, but had such a bomb ever been given a very high altitude test directly in the mesospheric layer of the atmosphere, 50 or 80km up, whether as a demonstration of strength or for any other reason; one can guess that it might have damaged the “silver cloud” layer far more severely than the Tungus event (only 10km up), causing a much steeper self-sustaining rise in global temperatures if the “silver cloud” theory of global warming is right.

Perhaps we may all have to start thinking far more kindly of President Nixon and Leonid Brezhnev; who signed the ABM treaty in 1972 severely limiting the development of such weapons, as well as President Johnson, who initially proposed such a treaty in 1967.

It is sobering enough to count up the number of times the American scientists who built the first atomic bomb employed, amongst many other shortcuts, Occam's Razor to help predict the effects of the bomb, in particular, whether it might be astronomically more powerful than they imagined. In one very important respect they are known to have erred on the side of simplicity and Occam's Razor – judging that lingering radiation and the effects of radiation from nuclear explosions on the health of survivors would be minimal.

[1] CO2 is believed to drive the changes in climate, but water vapor does most of the work of reflecting heat radiated from earth, back to earth

[2] Contrary to most people's intuition, meteorites above a certain size are actually much more likely to explode in the atmosphere and not reach the ground. Most meteorites that reach the ground relatively intact do so because the atmosphere slowed them down fairly quickly, before they were heated to the point of vaporizing. So one shouldn't conclude from the fact that the Tungus meteor exploded that it was small or not very dense. The opposite is true – even though truly huge meteors will also penetrate the atmosphere largely intact.

[3] Granted these were also large bombs, often measured in megatons, but these explosions occurred much lower in the atmosphere than 10 km, where the meterorite is thought to have exploded, so nuclear tests didn't affect the high atmosphere significantly.

# posted by Russell @ 1:12 PM