The Year Without Summer by William K. Klingaman, Nicholas P. Klingaman Read Free Book Online Page A

grandfathers
     tossed water into the air, it “would be Turned into Ice e’re it came unto the Ground.”)
     Mather ascribed the changing climate to the settlers’ destruction of forests and their
     cultivation of ever-greater tracts of land, which presumably allowed the sun’s rays
     to better penetrate and warm the earth.
    Nearly a century later, Thomas Jefferson seconded Mather’s deforestation theory, although
     the two men would have agreed on little else. An obsessive record-keeper who spent
     a lifetime searching for meaning in America’s physical environment, Jefferson faithfully
     recorded the temperature nearly every day—and often twice a day—for fifty years. (He
     even noted the weather in Philadelphia on July 4, 1776, when members of the Continental
     Congress signed the Declaration of Independence: 76 degrees at one o’clock in the
     afternoon.) Based upon his personal observations and anecdotal evidence, Jefferson
     suggested in 1781 that Virginia’s climate was indeed changing. Not only were winters
     less severe than they had been several decades earlier, but summers were cooler than
     before. “Both heats and colds are become much more moderate within the memory even
     of the middle-aged. Snows are less frequent and less deep.… The elderly inform me
     the earth used to be covered with snow about three months in every year. The rivers,
     which then seldom failed to freeze over in the course of the winter, scarcely ever
     do so now.” Twenty-five years later, this notion apparently had become so widespread
     that Jefferson could write that “it is a common opinion that the climates of the several
     States, of our Union, have undergone a sensible change since the dates of their first
     settlements; that the degrees both of cold and heat are moderated.”
    Among those who concurred were French historian and philosopher Constantin-François
     de Chasseboeuf (who renamed himself the Comte de Volney). After traveling through
     the United States in 1795–98, Volney attributed the perceived climate change in North
     America to deforestation. To support his theory, he quoted an early history of Vermont,
     which claimed that conditions “in the cultivated part of the country” had changed
     dramatically since English settlers first arrived in New England: “The seasons are
     different, the weather more variable, the winter become shorter, and interrupted by
     great and sudden thaws. Spring is a scene of continual vicissitude … Summer is not
     so hot, but it lasts longer. Autumn is most tardy in beginning and ending … nor does
     winter become settled and severe before the end of December.”
    “It is a popular opinion that the temperature of the winter season, in northern latitudes,
     has suffered a material change, and become warmer in modern, than it was in ancient
     times,” concluded Noah Webster in a speech to the Connecticut Academy of Sciences
     in 1799. “This opinion has been adopted and maintained by many writers of reputation”—Webster
     cited Jefferson, Dr. Samuel Williams, a weather expert and former Harvard professor,
     and Massachusetts physician Edward Augustus Holyoke—“indeed, I know not whether any
     person, in this age, has ever questioned the fact.” Webster himself believed that
     “the weather, in modern winters, is more consistent, than when the earth was covered
     with wood, at the first settlement of Europeans in this country.” The warm weather
     of autumn, he argued, extended further into the winter months due to “the greater
     quantity of heat accumulated in the earth in summer, since the ground has been cleared
     of wood, and exposed to the rays of the sun.” Similarly, “the exposure of its uncovered
     surface to the cold atmosphere” allowed frost to penetrate the ground to a greater
     depth in winter, which appeared to delay the advent of summer weather.
    Nonsense, countered William Dunbar, a Scottish-born scientist who had emigrated to