Page:Popular Science Monthly Volume 69.djvu/465

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CHANGES OF CLIMATE 461

for one of the earlv-settled sections of the United States, beginning with the date of the first white settlements and extending down to the present day, we should have the following situation : Dividing this list into halves, each division containing an equal number of years, it would be found, speaking in general terms, that for every mild winter in the first half there would be a mild winter in the second; for every long- continued drought in the first division there would be a similar drought in the second; for every ' old-fashioned ' winter in the first group there would be an ' old-fashioned ' winter in the second. And so on through the list. In other words, weather and climate have not changed from the time of the landing of the earliest pilgrims on the inhospitable shores of New England down to the present day.

Vfhy the Popular Belief in Climatic Changes is Untrustworthy. — Why is the popular belief in a change of climate so widespread and so firmly fixed, when instrumental records all go to show that this belief is erroneous? It is not easy to answer this question satisfactorily, but several possible explanations may be given. The trouble arises chiefly from the fact that we place absolute trust in our memories, and attempt to judge such subtle things as climatic changes on the basis of these memories, which are at best short, defective, and in the highest degree untrustworthy. We are likely to exaggerate past events; to remember a few exceptional seasons which, for one reason or another, made a deep impression on us, and we thus very much overrate some special event. To make use of an illustration given by another, indi- vidual severe winters which, as they occur, may be some years apart, seem, when looked back upon from a distance of several years later, to have been close together. It is much as in the case of the telegraph poles along a railroad track. When we are near the individual poles they seem fairly far apart, but when we look down the track, the poles seem to stand close together. The difference in the impressions made upon youthful and adult minds may account for part of this miscon- ception regarding changes of climate. To a youthful mind a heavy snowstorm is a memorable thing. It makes a deep impression, which lasts long and which in later years, when snowstorms are just as heavy, seems to dwarf the recent storms in comparison with the older. The same is true regarding heavy rains, or floods, or droughts.

Changes of residence may account for some of the prevailing ideas about climate. One who was brought up as a child in the country, where snow drifts deeply and where roads are not quickly broken out, and who later removes to a city, where the temperatures are slightly higher, where the houses are warmer, and where the snow is quickly removed from the streets, naturally thinks that the winters are milder and less snowy than when he was a boy. Similarly, a change of resi- dence from a hill to a valley, or vice versa, or from the coast to the

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