Climate And Man

( Originally Published Early 1900's )

MUCH confusion fills the minds of many persons with respect to the full meaning of the terms weather and climate. In consequence we hear people refer to climate when they mean weather and to weather when they are thinking of climate. In the preceding chapters we have analyzed weather but not defined it. Perhaps we should have done so before now. Certainly we are ready for the definition now. In simple and brief terms, weather is merely the state of the atmosphere at any given moment. By "state of the atmosphere" is meant of course all the factors which we have detailed, such for example as those included in the weather observer's report when he makes a morning or evening observation for use on the weather map. Climate differs from weather only in point of time and includes all that is meant by the weather. Climate is defined as the sum total of the average weather conditions taken over a long period of time, generally not less than ten years.

In other words, climate represents an average and implies years instead of moments.

Since climate includes many phases making up the atmospheric conditions, such as temperature range, precipitation, wind velocity and direction, barometric pressure, cloudiness, storminess, and other characteristics, reference to climate as "warm" or "dry" obviously is incomplete. Yet we know that most persons describe climate in such terms, and often, when asked to present further details, are unable to enlighten us much. We have the habit of describing climates in terms of one or two weather elements which dominate a given locality and impress us most. In a sense, people should not be criticized for. such technical inadequacy of statement, for the average person is not a specialist in weather or climatic observations and can only be expected to be impressed by those elements which either please or displease him most. That is human nature. For the technician, however, the whole story must be known and, furthermore, must be produced in statistical terms rather than in wordy generalities.

That many different types of climate prevail is common knowledge and therefore it will not be necessary here to record, classify, and de-scribe them all. Most persons recognize climatic contrasts through the annual migrations of birds and people along north-south directions. While most of the birds leave the northern portions of the United States rather early in autumn, the people begin their migration about Christmas time, returning northward in March, when the birds begin their return flight. Naturally, only that part of the public migrates which has the time, the money, and the inclination to do so. This migratory movement is not into a broad climatic zone but rather to a few spots, such as the West Indies, Florida, and portions of the Gulf coast as far west as the vicinity of New Orleans. A few find their way to southern California and some go to Bermuda. Yet in the face of such familiarity with the localized character of climates, our persistence in :referring to the age-old simple Greek' classification of climatic zones is nothing short of astounding. The word climate is derived from the Greek "klima," meaning "to incline," which was applied to the inclination of the earth's axis. While we have no evidence that this word as used originally was applied as to-day, yet it apparently had an astronomical meaning which is still current in many of our modern school textbooks. No doubt the popular error of referring to the climates of the earth as of three types, frigid, temperate, and torrid, may be traced to this unfortunate textbook tradition. Occasionally torrid is called tropical and frigid is referred to as arctic. Again, these names are employed to describe zones, which in turn are delimited by the parallels of 23½° north and south of the equator. Zone suggests a belt-like arrangement ; yet not a single type of climate encircles the earth in a belt-like manner. Certainly this is a most curious situation to be met in the present day of advanced scientific knowledge and among a people of high intelligence. But, as we have already suggested, the mass of people are reluctant to change from the old order of events, and so the delightfully simple but grossly inaccurate classification of climates and ideas of climatic zones continue.

To illustrate the points we have. just been making, let us consider concretely a portion of the so-called temperate zone both from the stand-point of the term temperate and the idea conveyed by the word zone. We have indicated the general interpretation of the latter word but not the former. Temperate may mean different things in different minds, but on the whole we should be safe in assuming the following characteristics to be those thought of as belonging to a "temperate zone" the four seasons, spring, summer, autumn, and winter, all characterized by moderate ranges of temperature and precipitation, but more than 50 to 60 per cent cloudiness, and no excessive winds except as may occur briefly in association with thunder-storms or for a day or two on the margin between a high and a low pressure area. Conditions such as we find, for example, in central Ohio probably represent on the average what most people think of as temperate. Now suppose we follow around the earth the parallel of 40° N. latitude, on which Ohio swings, and observe here and there the ex-tent to which the temperate zone is temperate and the zone a zone.

Traveling eastward from Ohio, we find conditions generally similar as far as the Atlantic coast, although on the heights of the Appalachians there are local deviations and along the New Jersey coast winter temperatures are less severe than in the interior. However, conditions are still such as to allow of their being designated as temperate. Crossing the Atlantic along the same parallel, we still are in a temperate climate, al-though the winds are much stronger than on the land and in places cloudiness is about 10 per cent higher. Precipitation data are not available. In crossing the sea we have passed over the Gulf Stream Drift, above which temperatures average higher than on either side. Arriving at the European coast, we continue across Portugal, Spain, and the Mediterranean through the heel of southern Italy, across central Greece, and into the high mountains of Asia Minor. 'Who would place Ohio and Pennsylvania in the same climatic class with the citrus fruit and olive producing areas of the Mediterranean? We should no more do that than to say that these States had the same type of climate as Florida or southern California. Yet some people name all these climates temperate and expect to be clearly under-stood. Climatologists have adopted the characteristics of the atmosphere along the southern French coast, the Italian, and parts of the Greek coast as distinctive of a climate worthy of a special name Mediterranean. This name is applied to the climate of southern California and some-times to the Gulf of Mexico area.

Let us proceed along the fortieth parallel into arid Turkestan and through the heart of the Tarim Basin, one of the earth's worst deserts, and on across the unfriendly Gobi Desert into northern China proper, to northern Japan, and the Pacific coast. Surely no one would classify the relentless deserts of Asia as temperate. They are not even temperate as deserts go, and as for including them under the same climatic heading as Mediterranean climates, that is unthinkable. Proceeding across the Pacific Ocean, we return to the United States, where the northern California coast is met, and, after climbing the rainy Coast Range and the Sierra Nevadas, again come upon a desert the Great Basin although not as severe as those of Asia. Leaving the desert behind us once more, we ascend a mountain range, the imposing Rockies, then descend into the semi-arid great plains, and emerging from this dry region approach the humid "temperate" neighborhood of Ohio. In crossing western United States we have experienced a frigid climate upon some mountain tops, a hot desert climate, a semi-arid climate, and a moderately humid climate. Can it be that we mean all of these things by the word temperate? Surely it is time that we abandon this old-fashioned term. It must be clear, too, after this world tour, that we have not followed a belt or zone that can be identified by a single type of climate.

We could trace the climates of the earth along other parallels and find similar contrasts and varieties. We refer briefly only to one other parallel namely, the equator. There are those who labor under the impression that an equatorial climate is identical with a tropical or torrid climate. At some places it is, but if we follow the equator across South America we shall discover that where it crosses the high Andes a torrid or tropical climate ceases to exist. Here, at elevations of twelve to fifteen thousand feet or more, the annual precipitation and temperatures are moderate and the vegetation is of an alpine character in contrast with the semi-jungles of the Amazon lowlands.

A visit to Africa along the equator reveals a similar situation where the low, forbidding Congo Valley heads into the delightful highland area of the eastern lake district. When Roosevelt planned his hunting trip into equatorial Africa many of his advisers feared for his life. They imagined excessive rains, the insect-infested jungles, tropical diseases, and recalled the heroic names of Stanley and Livingstone, who explored along the treacherous Congo itself. But Roosevelt entertained no such ideas, for he had studied the region and planned to enter it from the port of Mombasa, on the east coast. He knew that the plateau, attaining a height of 5,000 feet and peaks rising to 14,000 feet, moderated the heat along the equator and eliminated the normal discomforts of the jungle. He knew that he would not have to contend with a tropical or torrid climate. The geography textbooks that still continue to pursue the idea of belts or zones of climate around the earth made no appeal to Roosevelt. They should make none to the rest of us. Some may properly ask, "What shall we substitute?"

In place of the term zone, region or area may be used. A climatic region or area has reference to a locality whose shape is not defined. It may be belt-like, circular, rectangular, or any other shape ; it may extend over hundreds or thou-sands of square miles; it may half encircle the earth. The term region does not commit us to the restricted meaning of zone, but on the other hand invites great flexibility.

As a substitute for the three idealistic climatic classes, frigid, temperate, and torrid, we have nothing so simple to offer because, as we have endeavored to demonstrate, the climates of the earth cannot be classified into three such groups. Many attempts have been made to arrive at a standard classification but as yet to no avail. Classifications known as Supan's, Woeikof's, Köppen's, Herbertson's, and others have been recommended from time to time. Combinations of some of these scientists' works have been set up. No standard classification is suggested here, but rather attention is directed to the fallacy of the all too common popular reference to the earth's climates, and recognition is urged of climates, numerous in kind and relatively limited in extent. Some of the elaborate classifications referred to include from fourteen to twenty-five or more climatic types. For those desirous of learning these details, Ward's interesting volume on "Climate" offers a brief and clear presentation.

Although we seem opposed to abandoning these old climatic schemes even when we recognize their weakness, yet we appear willing to believe that the climates are changing when our meteorologists tell us they are not. The popular belief of the changing seasons, particularly winters, has been discussed. Let us consider the findings and views of investigators who have de-voted much time to the study of the important problem of climatic changes.

Geologists have long recognized climatic changes during the millions or billions of years of the earth's history. If their interpretation of the origin of coal is correct, then the era when coal was in the process of formation was one of subtropical climate. Biblical history implies that the activities of the peoples of the Holy Land and the eastern Mediterranean could have been realized only under a climate more moist than that of the present. The petrified trees of our south-western desert seem to present evidence of a climate which must have been wet enough to have supported the growth of the great forests which they represent. These and other phenomena have led men to consider quite seriously in recent times whether climatic changes have occurred at short or long intervals and, if at all, what the nature of such changes could be and what their cause. The problems, by their very nature, are exceedingly complicated and by no means solved as yet. But much light is being revealed.

Professor Eduard Bruckner, late of the University of Vienna, spent much of his time collecting weather data from as far back through the centuries as possible and plotted them to study such variations as they might show. From statistics more or less scattered over the past 200 years he concluded that certain oscillations occur, particularly in temperature and rainfall, but no permanent climatic changes. He saw fluctuations which tended to run in cycles of thirty-five years, and these have become known as the Bruckner Cycles. For example, during the years 1815-50 a number of places over the earth, as at Bremen, Germany, Mudus, India, and Nevchinsk, Siberia, experienced a rainfall maximum, after which there was a decline until about 1860-70, followed by an increase which reached its peak about 1880, whereupon another decline set in. Minor shorter fluctuations of twenty-one years and eleven years have been noted. These correspond, too, in general with variations in sun-spot frequency. However, recent investigations to check against the Bruckner Cycles have thrown much doubt upon their validity, having revealed shorter periods and not particularly regular.

Interesting studies have been made by Dr. D. T. MacDougal in California, Colorado, and elsewhere in southwestern United States upon climatic changes or fluctuations in terms of tree rings. If one cuts a tree at right angles to the trunk, a series of rings or bands of wood can be seen. Each of these represents a year of growth, and the thickness and other characteristics indicate whether growth was rapid or slow, which in turn serves as an index of the amount of moisture available each year. The conclusions thus far reached point to fluctuations which correspond to the Bruckner Cycles and also sun-spot variations. These tree-growth studies are especially fascinating, as they tell a story of events going back at least 3,000 years.

One more source of data of recent origin is contributing some evidence relative to climatic fluctuations. This refers to clay varves or layers, which were first investigated by the brilliant Swedish geologist Gerhard de Geer and subsequently studied by a young colleague, Ernst Antevs. If a clay bank representing a glacial deposit be cut into with a sharp instrument so as to reveal its banded structure, there is noticeable a variation in the thickness of the bands and their structure. These Swedish geologists see in them the history of climatic variations going back 5,000 years or more. The details of this type of evidence cannot be considered here, but a knowledge of the existence of this method of studying past climates is essential to any presentation of the various methods being emphasized in an effort to solve these problems.

We may conclude, then, from these considerations that, within the life of the average person, slight variations in the weather from year to year or over periods of several years may be realized, but no notable changes occur in so short a period of time. Further, no permanent changes in climate occur within such short periods as a few hundred years. Those persons who insist that a permanent change in climate has occurred within their own lives or within the combined years rep-resented by themselves, their parents, or grand-parents are in error. Only recently have we had a striking illustration of the error of the public in this connection. For the past five or six years people in Ohio have been emphatic in their belief that our climate has changed. The continuously low temperatures and abundant snowfall during the winter period of 1928–29 brought forth al-most a unanimous concert of comment to the effeet that "this was a regular old-fashioned win-ter." The public admitted that perhaps the climate was not changing.

Students of the progress of mankind have believed for some time that one of the most influential contributing factors toward advancement has been the "spur of the seasons." They have argued that man living in the climatic realms where a non-growing season alternated with a growing season makes greater progress than man gaining a livelihood in an environment where crops can be produced the year round. The logic of such contentions seems good. Most of us appreciate from personal experience that we would not do more than is requisite to our immediate maintenance if we did not desire ultimately to achieve enough leisure to enjoy art, music, travel, study, or play. Consequently, after we have earned enough to live on from day to day, we continue to labor further in order to provide a surplus with which we hope eventually to realize our ambition. In the rainy tropics, where no surplus production of food is necessary, there is no stimulus to extra effort.

Man makes his maximum cultural advances during his leisure, his first concern always being to obtain food. Occasionally one hears persons say that food is not their primary objective. In fact, they take offense if so accused. They may be readily convinced if they will go without food for several days and then attend a theater performance, a musicale, or even a neighborhood social. If any of these events proves enjoyable under such conditions, then the person is indeed a very unusual type. If we must prepare a food surplus for the seasons when foods may not be grown, we must invent ways and means for producing not alone enough for current needs but to carry us over the non-producing months. That means the invention of labor-saving machinery, of storage warehouses, of refrigeration plants, of rapid transportation, and a thousand and one other devices such as we now possess which have enabled us to reach our present stage of economic and social development.

Having provided for our food needs during the non-growing season, we then have time to relax and devote our energies to the so-called cultural elements in life. We advance the arts, literature, music, and sciences. Obviously, similar accomplishments could not be attained if the growing season proved too short to make possible a considerable surplus. The Lapps and certain northern Russian tribes occupying the tundras are in this position. They find it necessary to migrate with the sun and barely eke out an existence during twelve months of the year. Their struggle for existence is so severe that they have no opportunity for leisure and hence little or none for invention and for the growth of culture. Going to the other extreme, where gaining a food supply is relatively easy throughout the year, as in the rainy tropics, there is no spur to produce more than the immediate requirements, hence no stimulus to invention and therefore none to progress.

This matter of progress, then, represents a delicate balance between a condition that does not foster too easy an existence and one that does not tax man's endurance too severely. However, we would be making a serious error if we did not recognize, as a part of the condition contributing to progress, man's intellect. In the most favorable climatic environment, man, without the intellect to convert the elements about him to his ad-vantage, could hardly be expected to rise above the level of the occupant of the rainy tropics or the inhabitant of cold or hot desert regions who continually struggles with the most adverse physical conditions.

Civilization began its development in areas now largely desert, that is, southwestern Asia. Whether that territory has always been desert is not certain, as we have already indicated. Whether it has or has not been arid, we know the spread of civilization was effected in a westerly and northerly direction. It moved from the eastern Mediterranean to Greece and Rome as focal centers, and then northward across the Alpine highland and along the major river valleys of Europe, including the Danube, the Rhine, the Rhône-Saône, the Seine, and others. As modern civilization established itself firmly in northwestern Europe, the remarkably advanced forms which characterized the climax accomplishments of the Greek and Roman empires steadily declined. Many reasons for the fall of the Greek and Roman civilizations have been as-signed, and among them climatic change has been argued. Ellsworth Huntington contends the possibility of more rainfall than at present when these civilizations reigned supreme, a condition which would have encouraged a better agricultural development, a great variability in weather, and consequent greater stimulus to both physical and mental activity. To further substantiate his theory, he has made extensive studies of the relation between climates of to-day and degree of civilization, and concludes that "a favorable climate is an essential condition of high civilization." At the same time he is not unmindful of the importance of intellect. In spite of his enthusiasm for the climatic theory, he does not go so far as to say that a favorable climate automatically produces a high type of civilization. On the other hand, given a high order of intellect in two different climatic environments, one favorable and one unfavorable, the most favorable climate should stimulate the more rapid progress and therefore the more advanced civilization. These theories contain many fascinating ideas deserving of further investigation by many people, to the end that either they be shown to possess truth or they be demonstrated to be in error. In the light of the historic spread of modern civilization, it hardly seems possible that civilization is unrelated to climate.

One may ask at this point, "What is a favorable climate?" Here we must again turn to Huntington for what seems to be the only available answer in terms of exact figures. He locates the place having a climate approaching closest to the ideal, in England, for here the storm frequency that is, atmospheric pressure changes is high, while the changes in the characteristics of the weather from one season to another are moderate. The temperature average for winter is between 38° F. and 40° F. and for summer 60° F. to 65 ° F. While periods of excessive moisture in the air are not uncommon, the relative humidity averages most of the time close to 70 per cent.

The shifts in temperature from day to day are not extreme. Such contrasts as occur, for example, in the upper Mississippi Valley, amounting to from thirty-five to sixty degrees in twenty-four hours or less, are uncommon in most parts of England. These conditions are set as ideal for the average worker.

Clearly, there can be no ideal climate to meet every purpose. Here is a city advertisement appealing to the business man, which proclaims, "Climate is ideal for industry no snow, no enervating heat." Other centers advertise their climates as ideal for a winter vacation, or ideal for persons suffering from various and sundry diseases. Out of these claims for climatic ideality, at least one conclusion may safely be drawn namely, that we recognize the sensitiveness of man to climatic conditions. We need to give the matter much more detailed study. The establishment of definite information as to this relationship would prove of inestimable value. For example, we assume that because a person is born in New York State he is well adapted to live there. If our reactions to climatic phenomena were definitely known, we might find that this particular New Yorker would thrive far better in Montana or southern California or northern Minnesota. Now and then physicians suggest "a change of climate" for a patient, but all too often the suggestion is founded upon guesswork rather than actual knowledge. While it may not always be feasible for a child to shift its home from its birthplace to some other region, yet frequently such shifts wisely made might mean the difference between ill health and a robust body, the difference between suffering during a short life and the enjoyment of the delights that may come from a long life.