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Global Climate Change: According to Hoyle... and Wickramasinghe Too!
Volume 4, Number 14: 4 April 2001

The last two million years have seen earth's climate regularly oscillate back and forth between glacial and interglacial conditions, the former lasting approximately 90,000 years each and the latter lasting about 10,000 years each.  Scientists have long struggled to understand the underlying basis of this geological clockwork pattern, as well as what makes it tick.  For the past several decades, theories based on the thinking of Milankovitch, which attribute the periodic climatic pattern to regular variations in earth's orbital parameters, have enjoyed much prominence.  Hoyle and Wickramasinghe, however, present several reasons why such theories cannot be correct; and they develop a new theory of the phenomenon that has many important implications.

Their take on the subject begins about 50 million years ago, when ocean bottom-water temperatures were approximately 15°C.  The available heat in the world's oceans at that time was equivalent to about a 50-year dose of solar radiation.  This energy supply was sufficient to maintain earth's climate in an equable state that was capable of weathering random perturbations that, in its absence, could rapidly have returned the planet to full glacial conditions.  As time progressed, however, Hoyle and Wickramasinghe note that the positioning of Antarctica and Greenland at or close to the poles eventually led to their being covered by ice.  Very cold meltwater from Arctic glaciers then gradually led to the bottom waters of the world's oceans being filled with water close to its freezing point, leaving the planet's oceans with only about a three-year supply of solar energy stored in a surface layer but a few hundred meters thick.  This greatly reduced thermal buffering capacity of earth's seas was by this time small enough that random climatic perturbations had a much greater chance of triggering full-fledged ice-age conditions, which would have reigned supreme indefinitely were it not for what Hoyle and Wickramasinghe suggest is the cause of the much shorter interglacial periods that have regularly punctuated the extreme coldness that would otherwise have been the planet's everlasting fate.

Can you guess the identity of the mechanism that overcomes the world's natural tendency for maintaining eternal wintry conditions in its current heat-starved state?  Knowing that Hoyle and Wickramasinghe are its champions should make it easy.  The answer they propose is comets, specifically, one-kilometer-sized comets, which they calculate should have a probability of striking one of earth's oceans about once every hundred thousand years, which essentially matches the periodicity of Pleistocene interglacial reoccurrences.  Such events, they further calculate, would have the power to eject sufficient water into the stratosphere to produce a powerful greenhouse effect of sufficient duration to "jerk the earth almost discontinuously out of a long drawn-out ice-age into the beginning of an interglacial," following which the subsequent natural progression of random climatic perturbations would gradually prime the planet for a return to its normal Pleistocene state of full glaciation.

So what does all this have to do with CO2 and global warming?  Be patient; we'll get there.  But first we must consider what type of perturbation could send the planet reeling into the next scheduled ice age.  High on Hoyle and Wickramasinghe's list of potential triggering mechanisms is the creation of ice crystals in the upper reaches of the atmosphere, such as those that form over Antarctica during Southern Hemispheric winter.  Such particles have a tremendous cooling power over the planet, as they are highly reflective of incoming solar radiation; and it would take only a small amount of them to dramatically raise the planet's albedo, sending us hurtling towards a rendezvous with cold so extreme that most of the biosphere would perish in the process.

What keeps us from this fate?  Hoyle and Wickramasinghe's analysis shows it is the latent heat supplied by the condensation of water vapor, carried upward by convection currents, that provides the warmth needed to keep the dreaded ice crystals at bay; and they calculate that to be successful in this regard, enough moisture must be wafted upward to provide for an annual average precipitation total over the world of approximately 50 cm.  Currently, mean global precipitation is about 80 cm, so we are safe; but, as the scientists say, "not by a wide margin."

What is their prescription for a better safety margin?  "We must look to a sustained greenhouse effect to maintain the present advantageous world climate," they say, for "the renewal of ice-age conditions would render a large fraction of the world's major food-growing areas inoperable, and so would inevitably lead to the extinction of most of the present human population."  Indeed, Hoyle and Wickramasinghe indicate that "without some artificial means of giving positive feedback to the climate, ...an eventual drift into ice-age conditions appears inevitable."

The policy implications of Hoyle and Wickramasinghe's analysis are clear, crystal-clear, in fact; and they state them without equivocation.  "Manifestly, we need all the greenhouse we can get," they say, noting that "those who have engaged in uncritical scaremongering over an enhanced greenhouse effect raising the Earth's temperature by a degree or two should be seen as both misguided and dangerous," for the problem of the present "is of a drift back into an ice-age, not away from an ice-age."

The bottom line is this: we have long claimed, and cited mountains of experimental evidence to support our claim, that the ongoing rise in the air's CO2 content is having a direct positive impact on earth's plant life.  Hoyle and Wickramasinghe have now done the same with respect to earth's climate.  Hence, it is abundantly clear that President Bush's dual decision to scrap the Kyoto Protocol and not cap utility CO2 emissions was the right one.  It was right for the United States, it was right for the world, and it was right for the only biosphere in the universe of which we have any direct knowledge.  Misguided and dangerous voices, as Hoyle and Wickramasinghe describe them, will continue to clamor for CO2 emission restrictions (see the current issue of Time magazine, for example); but they are clearly in the wrong.  Science has spoken; and it has said what more and more people are beginning to realize when they stop and seriously consider the evidence: CO2 is the elixir of life and the protector of our climate as well.

Dr. Craig D. Idso
President
Dr. Keith E. Idso
Vice President

Reference
Hoyle, F. and Wickramasinghe, C.  2001.  Cometary impacts and ice-ages.  Astrophysics and Space Science 275: 367-376.