by George W. Harper

Before throwing anything out, it's a good idea to make
sure you don't need it. Could this be such a case?

It is recorded that during the waning days of the last century, a modestly prominent middle-aged astronomer had to be pulled from atop a venerable geologist who obstinately persisted in arguing that geological evidence proved the earth must be at least 300 million years old. Astronomy had already established that the sun could not possibly have flamed more than 75 million years and for an obviously senile septuagenarian geologist to maintain a contrary opinion was an intolerable affront to the primacy of astronomers everywhere. To question an astronomer's professional opinion was heresy!

Modern astronomers are somewhat less violent but frequently no less complacent of their wisdom. Thus we find a recent diktat which ordains that if the human species does not promptly desist from spewing heat and particulate pollutants into the atmosphere the mean world temperature will rise about 9 degrees over the next century, melting the polar icecaps and flooding cities all over the world.

Just how we are to accomplish this in the face of colder winters and a rising human population is nowhere specified . . . a little genetic engineering so we all grow fur coats, perhaps . . . but the warning hardly qualifies as startling. In recent years a number of highly respected astronomers have pointed to Venus and gone on record warning us of the hazards of a runaway greenhouse effect where the buildup of atmospheric carbon dioxide traps heat from the sun and makes the world uninhabitable. The 9-degree prediction is simply an extension and refinement of the greenhouse warnings which focus primarily on the release of human-produced heat into the atmosphere. Both the long- and short-term perils are part of the pollution syndrome which has become so popular over the past few years.

Mention pollution to just about anyone and we are assured of the knee-jerk reaction: "Pollution! Ugh, that's awful. We've got to stop it before it kills everyone!" Pause to think a bit about this response and its pavlovian character starts to become disturbing. Anything capable of evoking so automatic a reaction is also susceptible of being misused . . . which recalls the remark by one one of our more illiterate TV commentators who, a few years ago, scornfully pointed out that in leaving excess equipment behind on the moon we were "now no longer content merely with polluting the earth but have started polluting the entire universe with our litter!" It is amazing how miniscule the universe becomes when challenged by a news commentator. It is on a par with the remark by another commentator who opined, "Now that we've conquered space it's time we turned our efforts to solving the problems here at home!"

Continuing in the same vein, anyone who wishes to liven up a dull party might try dropping a quiet comment that a little radiation is good for us. This is positively guaranteed to lead to a screeching confrontation by three or four individuals who are utterly convinced that radiation means death. "Radiation is pure pollution! Any amount is too much!" Try to explain that without nuclear radiation from the sun life becomes impossible on earth and they gasp, struggle briefly with an alien concept and dismiss it as something wholly irrelevant. Observe that in burying spent nuclear waste we actually are returning less radioactive material to the ground than was originally taken out and they stare blankly. They are so caught up in their fantasy of pollution they cannot grasp the elemental idea that when we extract energy from something we necessarily wind up with less energy than we started with. We may increase short-term radiation, but no matter how we want to cut it the sum total of radiational waste is less than was initially extracted. Sorry about that, but it's the truth.

Sadly, none of this makes any real difference. The word "pollution," as society currently uses it, has become virtually meaningless. It is now primarily a pejorative to describe anything the speaker dislikes. If you don't like dogs, then call their leaving "pollution" and run them out of town. If you dislike humans, call our waste "pollution" and demand we stop breathing. Dislike rock music? You shout "noise pollution" and call for its elimination. Not long ago, authorities of a Pacific coast community actively considered fencing off several hundred square miles around a mountain reservoir and killing off the animal life to prevent "pollution!" That this would produce an ecological catastrophe was not even considered. "Pollution" has become a buzz-word so broad in context, it now has at best only marginal significance. It has been polluted by pollution-criers!

As we see it, there are so-called "pollutants" that it is highly desirable or essential to eliminate from the environment. There are other "pollutants" which are iffy and probably should be reduced in the environment and, at least in the case of "air pollution" there is one which, if we successfully eradicate it . . . or even reduce it significantly . . . conceivably might lead to global catastrophe and possibly to the effective destruction of the human species!

We suspect even the chaps who today scream most shrilly about the need to eliminate air "pollution" would be a trifle disconcerted if they had to do their yelling from the bottom of a mile-thick ice sheet. It would be ironic justice, but the rest of us would have to suffer, too. And this is not so nice. It is entirely possible that a significant reduction in the air "pollution" index will lead directly and very quickly to a new glacial age which would smother our cities and farmlands under a massive sheet of ice.

Does this mean we question the possibility of a greenhouse effect? Are we flying in the face of observational evidence and denying its reality? Not in the least. Venus exists, so does greenhousing. But we take exception to the facile presumption that these facts are directly transferable from Venus to earth. Venus lacks water. Earth obviously does not. Venus is only 70 percent earth's distance from the sun, which means it receives roughtly twice as much heat per square centimeter of surface as earth. Earth, with its massive oceans, has evaporation and a build-up of atmospheric moisture in the form of clouds will reflect solar heat rather than absorbing it, thus largely neutralizing the effects of any man-made heat or carbon dioxide excess that may be present. In short, while it is theoretically possible that an excessive buildup of carbon dioxide in the atmosphere could trap enough heat to melt the polar ice caps and flood coastal areas around the world, we doubt as a practical matter whether there is a realistic likelihood of creating a Venus effect.

But suppose we postulate the possibility of greenhousing on earth, just ot see where it leads us. We burn fuel to warm our homes and run our transportation systems and factories. The fuel burned (except for hydrogen, nuclear, and fuel cell systems) releases carbon dioxide into the atmosphere, which leads to a buildup of heat which in turn leads to a general melting of ice caps and a dramatic increase in the percentage of earth's surface water cover . . . melting the ice caps would add roughly 10 percent to the existing land-to-water ratio, all of it in the form of shallow, evaporatively efficient tidewaters. The same heat that leads to the melting of polar ice caps also tends to increase evaporation and creates dense cloud layers which reduce the intensity of the solar radiation by reflection.

With the generally warmer temperature we need no longer use so much energy heating our homes, so the rate of carbon dioxide release into the atmosphere slows. In the meanwhile, the shallow tidewaters become prime breeding for vast quatities of algae which absorb carbon dioxide and release oxygen. Oceanic carbon dioxide absorption completes the picture and conditions stabilize, probably well short of a complete ice melt. The overall effect is a partial melt of the ice caps and some flooding of coastal areas around the world. But there is no Venus effect, and while the consequences may be rather uncomfortable, the human race would survive. We might have ourselves a steamy, carboniferous era climate where glimpses of the sun are rare and torrential rains sheet down daily, but the Venus effect per se does not occur.

Now suppose we look at some of the possible hazards of a significant reduction in air pollution. Astronomers may point to Venus, but geologists can point to earth. Over the last several million years our planet has endured a whole succession of ice ages, where mile-thick glaciers perched atop what is now Chicago, when what is now Miami was 100 miles inland, the Gulf Stream flowed eastward south of Cuba, and icebergs ground against the Bahamas peninsula and clogged the California coast.

The last five ice ages appear to have come at approximately half-million year intervals with the time between the end of one age and the onset of the next roughly 25,000 years. A look at the calendar therefore suggests we are about 10,000 years overdue for our next ice age! More pertinently, a study of earth's climatic history over the past 7,00 years argues that we may actually have entered a new ice age around 6,500 years ago, but for some reason it was aborted.

The evidence is moderately convincing. Roughly 6,500 years ago, earth's climate was halcyon. The snow line in Scandinavia was above the 8,000 foot level in many areas. Deciduous trees grew all the way to the arctic circle. The Sahara Desert region received adequate rainfall and the peoples of the Badarian culture roamed throughout the Saharan grasslands. The evidence for all this is decisive. Badarian artifacts are found strewn over areas where no rain has fallen for centuries. Satellites photographing the African desert have revealed the beds of several former rivers, all of which save the Nile had dried up by about 6,000 years ago.

By 3,500 years ago, the tree line in Scandinavia had dropped to around 6,000 feet and deciduous trees were in full retreat from the circle. Climate throughout the world was changing. Temperatures had started cooling and the snow lines on northern mountains crept lower each year. Growing seasons in Europe were shortening and the winters even in Italy and Greece became a little more severe with every passing season. The fertile lands of Samarkand cooled and dried and it became a desert.

A little less than 2,000 years ago the rains along the northern coast of Africa largely ceased, so today the erstwhile "breadbasket" of the Roman Empire is hard put to provide food for its own population, and is mainly desert. At the same time this was happening in Europe and Africa, the winters in central Asia had deteriorated to a point where hordes of nomad herdsmen form Siberia, made desperate by lack of food, erupted onto neighboring lands with sullen ferocity and a singled-minded determination to survive. The refugees driven from their homes by the northern invaders migrated into Europe where they became known as Huns, Avars, Vandals, etc., and promptly toppled the Roman Empire. Since the victors against Rome were the LOSERS of the battle for the Asian steppes, we can imagine the calamity that would have befallen Europe had the victors continued their pursuit!

Only a couple of centuries after the Huns and Vandals, the advancing cold made it no longer possible for Scandinavia to support its population. New waves of migration led to the Vikings and their conquests of Normandy, England, and Sicily and their discovery and settlement of Iceland and Greenland.

Thermal "pollution" from its volcanoes and geysers kept Iceland habitable, but the Greenland settlers had no such luck. The colony got off to a promising start and several settlements were established. A bishopric was created and the population grew to three or four thousand. But nothing could stop the ice. Each year grew a little colder. Every year the growing season was a bit shorter. Every year the ice sheet encroached farther onto the pastures and fields. Massive icebergs began clogging the oceans and prevented ships from stopping by. Greenland vanished from the European horizon for over 150 years. When the next ship arrived, there was no one there to greet it. The last survivors had died over a century earlier and in most places the snow and ice completely covered their old farmsteads.

Less than a thousand years ago, the cold was whistling down on the heartland of Europe. The Seine River froze solid in Paris, and wolves howled in the streets of the city as they fought the Parisians over the bodies of the dead. Ice formed regularly on the canals of Venice, and Rome experienced a succession of bitterly cold winters. Significantly, this same period saw the destruction of the Anasazi culture in the American southwest. This has already been associated with a prolonged drought and a succession of abnormally frigid winters, so we can be reasonably we are dealing with a worldwide phenomenon rather than a localized aberration.

But this was to prove the high-ice mark. Around 1200 A.D. the weather began reversing itself, slowly at first then with increasing speed as earth experienced a new warming trend which has lasted some seven centuries and only around 1950 started showing signs of turning cold once more.

There are several ways of accounting for this trend. Since knowledge of the fine detail of glaciation periods is scanty, we might call it a perfectly normal part of the glacial process; a preliminary cooling which lasts about 5,000 years followed by a respite of perhaps 700 years before going into a second cooling era with other brief interludes to follow. This is undoubtedly a legitimate way of interpreting the evidence. If correct, we may assume the earth is in for a new cooling spell which will outdo the last and mankind is in for some very nasty climate over the coming millennia.

A second way of accounting for the warming trend is more interesting. When the last glacial age started half a million years ago, man was something of a newcomer on the scene. The human population was probably no more than a few million, with the majority still living in semitropical regions. When the glaciers moved south, those of our ancestors who were confronted by the advancing ice retreated before it. A few campfires were lit, but that was the limit of human response.

In contrast to the last ice age, by the year 1200 A.D. the human population of earth stood at roughly 500 million, with the majority living in the northern hemisphere. Property and real estate rights were established institutions, something to be defended to the bitter end. A farmer does not desert his family plot without compelling reasons, and cities such as Rome, Athens, Paris, London, or even Moscow are not lightly abandoned. When cold comes you light a fire and tough it out. If it gets colder you add another log and continue to sit tight. By 1200 A.D. the earth's cooling trend was countered by the smoke millions of fireplaces, all belching heat, carbon dioxide, and soot into the atmosphere. Cold "pollution" was met by heat, soot, and carbon dioxide "pollution." The cold lost and earth gained a respite.

Which of the two alternative explanations is correct; or are perhaps both correct, with a natural respite being further augmented by human-caused air pollution? We lack the data to permit an absolute conclusion - partly because no one has looked for it - but there are some fascinating elements to consider.

Earth's weather is narrowly balanced between extremes, and a change of three or four degrees in the mean world temperature is enough to start an ice age, or end one. This is known data. We also know that even small cities spew enough heat into the air to create micro-climates overhead. It is the same principle as that used by Florida citrus growers when a freeze looms. Smudge pots cannot cope with heavy frosts but they are quite capable of muting the effects of a modest one. Of special significance is the fact that we do not het the same effect if we merely deploy a batch of electric heaters. "Pollution," or smog emitted by the smudge pots is essential if the remedy is to work. It creates an artificial cloud of sooty smoke which reflects the heat back and contains it over the citrus grove. Without the smudge the heat simply radiates off into space and is quickly dissipated. With the smudge, the same units of heat energy are multiply reflected and confined.

By clear implication, the medieval cities, small though they were by comparison with modern metropolitan areas, were still significant in creating islands of resistance to the cold and thus in modifying the prevailing weather patterns. As the population increased and more smokestacks belched out their "pollution" the climate was further eased. This effect MUST occur regardless of any natural slaking of the cold. In short, even if the recession of the mini ice-age was a natural consequence of the pattern of ice ages, we can still be certain that it was further ameliorated by human action. The only question is whether human activity is sufficient in itself to account for the reversal of the cold.

Here again is uncertainty. We lack the data to come up with an unambiguous answer. But the last half-century has provided some disturbing evidence. The British Isles are a good place to begin. For centuries London has been famed for its impenetrable fogs which swath the city for days on end during winter months. Starting around 1950 the English began switching from sooty coal pots to electricity for heating. Much of this power comes from clean nuclear sources, the rest from emission-efficient central generating systems. By 1960 the English countryside had become mostly soot-free and the notorious London fogs were largely a memory. But so were the warm, rainy winters which used to characterize the British climate. Instead the air is clear, the ground heat quickly dissipates into space, and temperatures have become abnormally cold with heavy winter snows commonplace.

France too is feeling the effects of a newly "pollution-reduced" environment. Clean, centralized energy has lowered air pollution and dropped temperatures. In the winter of 1984-85 a blizzard swept down on the Riviera and a number of campers froze to death on the Mediterranean coast - which is roughly equivalent to a snowstorm blanketing Honolulu! It is not something that just happens.

Paralleling the deepening cold in Europe is drought in Africa and elsewhere around the world. Lack of rain has led to a systematic southward march of the Sahara, commencing around the late 1950's and continuing uninterruptedly every year since. Then there is the succession of disappointing harvests which have afflicted the Soviet Union. Our propagandists cheerfully attribute the failures to inherent defects in the Soviet system, but while this may be a contributing factor the primary cause has been a steady worsening of the weather and frequent droughts over the past three decades.

This too may be connected with a reduction in suspended air particulates and atmospheric carbon dioxide. Water droplets form most readily when aquaphilic "pollutants" such as soot particles are adrift in the atmosphere to serve as condensation nuclei . . . witness the occasional successes of rainmakers seeding clouds with silver iodide crystals. It is therefore entirely possible that in our obsessive urge to eliminate air "pollution" we may have been the direct cause of the drought-induced famines now killing tens of millions of people throughout the world!

Nor has the United States been immune. As we have cleaned up our air, the climate has worsened. We may have made southern California marginally more endurable, but on the other side of the coin we find massive winter freezes devastating the fruit crops of Florida, whole successions of hurricanes lashing the eastern and southern seaboards, and droughts, abnormal freezes, heat waves, and floods pestering the Midwest. Every year for the past decade has seen new records for cold being set in the southlands. When Atlanta gets nearly a week of zero weather - as it did during the winter of 1984-85 - we have to call it unusual. Winter snows all over the nation have been getting heavier every year for the past decade, and the proportionality between precipitation in the form of rain and precipitation in the form of snow has been edging in the direction of snow. Keep at it a little longer and the whole nation may find itself in deep trouble.

We concede the possibility that all these phenomena would have occurred no matter what we did. Perhaps the mini ice-age briefly hesitated for reasons wholly unrelated to human activity and is now getting down to serious business. For that matter, possibly the climatic changes over the past 50 years are no more than minor statistical glitches which will straighten out over the next century. At the same time we should not ignore the fact that a number of profound changes changes in earth's climate have appeared only AFTER we set about deliberately cutting back on air pollution.

Some of these changes, for example the disappearance of London fogs, are demonstrably a consequence of the reduction. Others, such as the sub-Saharan drought, are less certain. But the indisputable fact remains that clear, unpolluted skies lead to rapid thermal loss while clouded skies make an excellent thermal blanket and retard heat dissipation. Clear, unpolluted skies are inefficient at transporting water over land. Optimum efficiency calls for considerable "pollutants" to serve as condensation nuclei and to help avoid the extremes where we either get no rain at all or suffer typical desert downpours where the clouds dump their loads all at once to create enormously erosive flash floods below.

We may even accept an argument that our relatively small reduction in air pollution is insufficient to cause climatic changes of the magnitude experienced in recent years. It is still a scientific certainty that at some point along the line the effort to eliminate air "pollution" must lead to colder winters and less rain. It is the other side of the coin to the Venus greenhouse effect and is inherent in the nature of the statement.

The process is three-pronged. For one, we have a clearer atmosphere where solar heat reaching the earth is reradiated back into space every night. This means less heat is available over the yearly cycle and the average ground temperature must be reduced. It implies a smaller underground heat buildup so when the first snows of winter fall they quickly deplete the available heat and the snow remains on the ground longer.

The second prong develops when the reduced aggregate usable solar heat leads to persistently colder arctic and antarctic temperatures and the expansion of the snow blanket. Snow is an extremely efficient reradiator of thermal energy. Increase the snow cover even temporarily and we find even more of the sun's heat being reflected back into space. This means less heat is available to warm earth.

Combining the three factors we arrive at a pattern where world temperature reduction tends to exponentiate. Most of the atmospheric moisture falls as snow so the non-glaciated areas become arid. Confinement of water in the form of snow and ice leads to a lowering of the sea level. This latter reduces the water surface area available for new evaporation which thereby increases the drought in the unglaciated. The system becomes self-perpetuating over a long term cycle.

Now let us suppose, purely for the sake of argument, that for the past 6,500 years our world has been making an all-out effort to whip up a new ice age but for the past few centuries man has unwittingly forestalled the cold by his use of fossil and wood fuels. We have not only held the cold at bay but have actually pushed it back a little. But it is a fragile victory where even a fractional percentage point of change in the index of air "pollutants" can tip the balance. If our hypothesis is even partially correct it may easily turn out that the one or two percent reduction in worldwide air "pollutants" achieved over the past 35 years will lead to a runaway refrigerator effect rather than the greenhouse effect so often cited by astronomers.

Should this happen one thing is certain: neither Russia nor the United States will sit back supinely and perish as the ice descends. Great nations do not die quietly, and when it comes to sheer survival no national leader will flinch from employing the most extreme tactics . . . which today means nukes. Thus our deep and abiding suspicion that in our eagerness to abolish the demon "air pollution" we may be guaranteeing a far worse catastrophe not far down the line.

But let's be positive for a minute. Perhaps the elimination of air pollution from the environment will not cause a new ice age. Possibly all this is unjustified pessimism on our part. We still have ample cause for concern, a concern arising from the fact that no one has bothered investigating the possibility. It is evident that the prophets of doom have evolved their mythology on the premise that earth is static and today's climate is all there is. Ice ages are gone and forgotten so there is no point in worrying about bringing on a new one. In the classical sense of the word they have advanced a half-baked idea based on the false-to-fact premise that earth is staic, and have failed to study either the implications or the long-term ramifications of their idea. And this is frightening! In today's technological society one or two men of scientific prestige may make a hasty or ill-conceived statement whose consequences a century or so down the line can be utterly catastrophic.

It has been said with some justification that the most dangerous of all ideas is the noble one, the sort of idea aimed at engaging the passions rather than the mind. "Pollution" is merely the latest of a whole series of such ideas. Mankind desperately needs a system to get at least a few people thinking about the consequences of these noble actions and ideas. There ought to be some organized group whose special function is to say, "So get rid of pollution. It's a great idea. Now what nasty side effects can throw a monkey wrench into the works?" This business of looking for possible damaging outcomes to glorious experiments is almost entirely lacking. It has been left to professional nay-sayers and panic-mongers who usually work from wholly inadequate data to arrive at absurd conclusions.

But the analysis of consequences is too important to be left in the hands of penny-dreadful national newspapers which base their sales on tales of women giving birth to alligators, of visits by the ghosts of dead movie stars, and the predictions of psychics who tell us of Mu, Lemuria, and Atlantis. We also feel it is entirely too important to be left to the mercies of polititians who look only as far as the next election or of business managers concerned solely with next year's profit and loss balance.

It would be nice to believe our university system could take up the slack and fill the niche, but since World War II most have become so beholden to political and corporate funding they do little more than rubber-stamp the decisions of their masters. What is really needed is a scientific Consumer's Digest type operation. Sadly, none is anywhere on the horizon.

Copied from Analog Science Fiction / Science Fact
October, 1986.