The Year Without Summer: 1816 and the Volcano That Darkened the World and Changed History Read online

  As Tambora’s stratospheric aerosol cloud began to cool temperatures by subtly reducing the amount of solar energy reaching the earth, the land and oceans would have resisted this cooling by transferring stored heat into the atmosphere, and cooling themselves as a result. By early 1816, the land, ocean, and atmosphere were shifting toward a new balance of energies, largely as a result of the solar-dimming effect of the aerosol cloud. The adjustment cooled first air, then land, and finally ocean temperatures across the globe. Using information from tree rings—the width of each ring is related to the growing conditions (mostly temperature and precipitation) that year—climatologists have determined that 1816 was the second-coldest year in the Northern Hemisphere since 1400, surpassed only by 1601, following the eruption of Huaynaputina in Peru. Even as the aerosol began to settle out of the atmosphere through gravity, it would take years for land and ocean temperatures to return to normal. And so 1817 was the fifth coldest, 1818 the twenty-second coldest, and 1819 the twenty-ninth coldest year in the Northern Hemisphere since 1400.

  In the meantime, the aerosol cloud had produced other noticeable optical phenomena, most notably a series of spectacular red, purple, and orange sunsets in London in the summer and autumn of 1815. Observers noted repeatedly that “the sky exhibited in places a fire,” with “crimson cirri” [high-altitude cirrus clouds, composed of fine ice particles] and “much redness in the twilight.” “The evening twilight has been generally coloured of late,” wrote one contemporary, “and at times streaked with converging shadows, the origin of which could not be traced to clouds intercepting the light.” On several particularly unsettled September nights, the storm clouds continued to glow various shades of red for half an hour after sunset.

  Sunsets typically appear yellow, orange, or red because atmospheric gases scatter blue light more effectively than other colors, skewing the visible-light spectrum toward red. The effect is even more pronounced when the sun is low on the horizon, since its light must pass through a thicker layer of the atmosphere to reach the ground, resulting in less blue and more red light.

  Stratospheric ash, dust, and soot particles from volcanic eruptions—or from pollution or fires—enhance this atmospheric scattering effect, leading to brilliant red sunsets. After the sun passes below the horizon and light no longer reaches the surface, some sunlight still passes through the upper portions of the atmosphere. Aerosol veils reflect this sunlight toward Earth, giving the colorful postsunset glows reported in London. So exceptional were these sunsets that Londoners commented on them repeatedly in letters, journals, and newspaper articles, which suggests that they likely were caused by the Tambora aerosol cloud rather than the heavy industrial pollution that habitually afflicted the city during that era. In fact, scientists have taken advantage of this effect by using the amount of red in contemporary paintings of sunsets to estimate the intensity of volcanic eruptions. Several Greek scientists, led by C. S. Zerefos, digitally measured the amount of red—relative to other primary colors—in more than 550 samples of landscape art by 181 artists from the sixteenth through the nineteenth centuries to produce estimates of the amount of volcanic ash in the air at various times. Paintings from the years following the Tambora eruption used the most red paint; those after Krakatoa came a close second.

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  AMERICANS greeted the year 1816 with confidence and optimism. They had recently concluded two and a half years of war with Great Britain, arguably the strongest and certainly the wealthiest nation in the world, and the conflict had ended essentially in a draw. Admittedly the British had captured and partially burned the nation’s capital, forcing President Madison and his wife, Dolley, to flee for their lives, accompanied by several wagons full of White House valuables and Cabinet papers stuffed into trunks. But American troops led by General Andrew Jackson had ended the fighting on such a positive note with their overwhelming victory over a numerically superior force of British regulars at New Orleans in January 1815, that many Americans believed they had actually won the War of 1812.

  European events since that time offered hope that the United States could look forward to a long period of peace, undisturbed by events abroad. On June 18, 1815, British and Prussian troops commanded by the Duke of Wellington and Marshal Blucher dealt a crushing defeat to Napoléon’s army outside the Belgian town of Waterloo. The outcome had hung in the balance for most of the day; Wellington later acknowledged that the battle had been “the nearest run thing you ever saw in your life.” It had been exactly a hundred days since Napoléon had entered Paris in triumph. This time, the Allied statesmen at Vienna gave the British government sole authority to choose the site of the Eagle’s exile—it selected the remote island of Saint Helena, in the South Atlantic—and sole responsibility for keeping him there. With Napoléon removed from the scene, it seemed unlikely that the United States would be drawn into European affairs anytime in the near future. “We are, happily, at peace with all the world,” exulted one Massachusetts congressman, “and there are no indications which threaten soon to disturb this tranquility.”

  Everything in the United States appeared to be expanding. Since 1789, the nation had added five new states and five territories. By European standards, the United States’s population was growing at an astonishing rate. In 1815, there were nearly 8.5 million Americans, twice as many as there had been only twenty-five years earlier. Immigration—primarily from northern and western Europe—contributed to this prolific growth, but most of the increase came from Americans who married young and had large families; on average, American women in the early nineteenth century had between seven and eight live births. It was also a very young population: 85 percent of the population was under the age of forty, including nearly all of the leaders of Congress.

  Slightly more than 80 percent of Americans were white, and in a nation where land was cheap but labor scarce, the vast majority of white adults—more than 80 percent—made their living as subsistence farmers. Most American farmers spent only a portion of their working hours tending their crops, however, doubling as coopers, or tanners, or blacksmiths, or shoemakers. Wives and children frequently carded wool or spun linen in the evenings after spending their days in the fields. Farm families produced enough goods for their own needs, and sold the rest. “Go into the interior of the country,” wrote Albert Gallatin, former secretary of the treasury, “and you will scarcely find a farmer who is not, in some degree, a trader. In a grazing part of the country, you will find them buying and selling cattle; in other parts you will find them distillers, tanners, or brick-makers.”

  Fewer than seven percent of Americans lived in cities, the largest of which were New York and Philadelphia, but neither even remotely approached the size of London or Manchester. Nearly all of the nation’s towns were located on the East Coast, relying on commerce for their prosperity. Most municipalities lacked any public sewer or water system, which meant that garbage, dead animals, and human waste routinely accumulated in the streets.

  Manufacturing remained relatively primitive. Beyond the products of farm families, most of the goods offered for sale were fashioned by mechanics working by hand, either in a small shop or at home. Transportation was even less advanced. Goods and passengers rarely traveled very far over land; American roads were notoriously poor, many no more than narrow, bumpy, overgrown trails that turned into quagmires when it rained. (Travelers told stories of horses actually drowning in the pits, and wagons sinking slowly out of sight.) It cost as much to send a ton of goods thirty miles from an ocean port inland as it did to ship it three thousand miles across the Atlantic. And progress was slow; a traveler who set out by carriage from Boston in April would not arrive in Charleston, South Carolina, until July. In 1802, Congress had authorized the construction of the National Road across the Appalachians, but fourteen years later the road had not yet crossed the Ohio River. Hence merchants and farmers continued to rely on river systems to move goods in the interior.

  Yet significant improvements lay close
at hand. Steamboats, dismissed as “floating smokestacks” by skeptical observers when Samuel Fulton’s prototype made its debut on the Hudson River in 1807, were slowly gaining popularity, especially on the Western rivers. And Governor DeWitt Clinton of New York had begun to elicit legislative support for the construction of a canal (derided by his critics as “Clinton’s Big Ditch” or “the Governor’s Gutter”) that would stretch across the state for 340 miles from Albany to Buffalo, through thick forests and disease-ridden swamps, connecting the Hudson River with the Great Lakes.

  Manufacturing was poised to expand as well. When the recent war temporarily deprived American consumers of British goods, New England merchants and entrepreneurs provided financial backing for scores of small-scale domestic textile “manufactories” that produced a total of $24 million worth of cotton goods and provided employment to nearly a hundred thousand men, women, and children. Americans produced an additional $19 million worth of woolen goods in 1815, and the Boston Manufacturing Company, headed by Frances Cabot Lowell, had recently completed the nation’s first integrated textile factory along the Charles River in Waltham, Massachusetts.

  In the aftermath of war, a new spirit of nationalism swept over the United States. For the past twenty-five years, the nation had been riven by deep divisions over domestic issues—primarily Alexander Hamilton’s economic proposals—and the war in Europe. The disagreements produced the first two political parties in the United States: the Federalists, led by Hamilton and John Adams, who were horrified at the disorder and excesses of the French Revolution; and the Democratic-Republicans, who shared Thomas Jefferson’s dislike of a strong central government, and Madison’s distrust of Great Britain.

  Lately, however, many Republicans had come to accept much of the Federalist domestic agenda; a powerful central government seemed less threatening if they controlled it, as they had since 1801. (Madison, however, had grown no more fond of Britain since the king’s troops burned the President’s Mansion in Washington; in early 1816 Madison was living in a private dwelling on the corner of New York Avenue and 18th Street known as the “Octagon House,” while workmen repaired and repainted the mansion, this time with white rather than gray paint.) Moderate Federalists who could recognize a lost cause were deserting to the opposition in increasing numbers. And a series of costly missteps by the dwindling band of hard-core Federalist stalwarts—including vocal opposition to the war effort and a thinly veiled threat by New England political leaders in December 1814 to secede—destroyed any hopes the Federalists may have entertained to regain power on the national level.

  Partisan rancor thus subsided, although it did not entirely disappear when the Fourteenth Congress concluded its regular session in the spring of 1816. Legislators spent much of their time debating economic issues. In early April, Congress approved the first protective tariff in the nation’s history. Several weeks later, legislators voted to establish a second Bank of the United States, to provide a uniform, stable currency and a source of credit for business ventures.

  Yet there remained many congressmen and voters, especially from rural areas, who distrusted the power of a central bank independent of popular control. These same critics demanded that the federal government cut taxes now that the war had ended. Since military expenditures during the war had sent the federal debt soaring to nearly $124 million, Congress hesitated to slash taxes and decrease revenue too rapidly. It did repeal all duties on domestic manufactures, but it retained several other minor taxes, including those on carriages and postage. Administration officials estimated that the new, higher tariff rates would bring in at least $25 million per year, which they claimed would be sufficient to pay the government’s routine civil and military expenses, fund annual increases in the size of the navy (which had proven woefully inadequate during the recent hostilities), and pay off the remaining debt in about twelve years.

  Before Congress adjourned, it also voted itself a pay raise. Since the first Congress convened in 1790, legislators had received six dollars per diem in lieu of a regular salary. Although the cost of living had increased by at least 75 percent over the past twenty-six years, their remuneration had not changed. Hence congressmen felt justified in approving the Compensation Act, which granted them an annual salary of $1,500. Few realized at that time that this measure would destroy many members’ political careers.

  As lawmakers departed Washington at the end of April, they congratulated themselves on accomplishing their tasks in an unusual display of good feelings. “Among the most auspicious appearances of the times, is the obliteration of party spirit,” declared a Southern representative. “No question at the present session of congress has been discussed or determined on the ground of party.… Let us then cherish these feelings; let us emulate each other only in serving our country with the more zeal, and the more fidelity.”

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  ON April 29, Americans noticed a large, irregular spot on the surface of the sun when they glanced skyward. One observer compared it to “a spider, having parts extending from the main body,” while another claimed that “its general appearance is not unlike that of a cluster of islands … surrounded by a belt of rocks.” A representative of the National Mathematical Academy in Philadelphia estimated the length of the spot at just under 40,000 miles, with a breadth of nearly 3,000 miles. It lay just north of the center of the sun’s surface, and its stationary nature over the course of a week led a group of American astronomers to dismiss their initial hypothesis that it might simply have been the planet Mercury moving across the face of the sun. Instead, they decided it was probably a wandering comet pulled in by the sun’s gravitational force.

  In its May 1816 issue, the North American Review cited the theories of Sir Frederick William Herschel, a British astronomer, who argued that the spots were “chasms in the [sun’s] atmosphere, occasioned by ascending currents of gaseous fuel.” Since there appeared to be “a variable emission of light and heat, intimately connected with the appearance and disappearance of spots,” Herschel theorized that “seasons of uncommon heat and cold, of fertility and barrenness, so far as they depend upon the supply of heat, are to be traced not so much to accidental causes near at hand, as to the inconstancy of the fountain.” (Herschel, a legendary figure in the history of astronomy, made numerous important discoveries, including Uranus and its two moons, but also believed the sun was inhabited, along with all the other planets and stars. He speculated that the sun’s surface was actually cool enough to support life; only the outer solar atmosphere was hot.)

  Others suggested that the sunspots were volcanoes on the surface of the sun, or “burning mountains of immense size; so that when the eruption is nearly ended and the smoke dissipated, the fierce flames are exposed, and appear as luminous spots.” Yet another explanation proposed the spots to be “a kind of excavation of the luminous fluid supposed to envelope [sic] the opake [sic] and solid body of the sun.” Even those who supported this concept found it difficult to imagine how any gap within a liquid could remain unfilled; one contributor to the Gentleman’s Magazine in Britain likened it to “no less a miracle than the passage of the Israelites through the Red Sea.” Perhaps, suggested a writer in the Baltimore American, “the Sun has cast forth several immense bodies, and … there is a danger of one of them coming in contact with our little tiney [sic] globe, when, in the horrible crash, we may experience another deluge, or suffer a terrible conflagration!”

  No one in 1816 understood that sunspots are formed by variations in the strength of the magnetic field that surrounds the sun. Occasionally, a portion of the magnetic field grows strong enough that the field coils back on itself and punctures the surface of the sun, a process which inhibits the fusion reactions that produce solar energy. This in turn reduces the temperature of the sun’s surface at the point of the puncture. Since the brightness of the sun’s surface is proportional to its temperature, the sunspots appear darker than the rest of the sun.

  Scientists in Europe and the United St
ates had regularly recorded sunspot activity with telescopes since the early seventeenth century, when several astronomers, including Galileo, first observed them. Most of the earliest sunspot observations were taken during the period now known as the Maunder Minimum—named for the English scientist Edward Maunder—that extended from 1645–1717, when sunspot activity was at an unusually low level. The near disappearance of sunspots in the 1650s puzzled astronomers, as did their sudden reemergence in the second decade of the eighteenth century.

  While individual sunspots occur almost randomly, the total number of spots follows a fairly predictable eleven-year cycle (a cycle that was discovered in 1844). But sunspot activity also varies over much longer periods of time which are less predictable and less regular than the short-term cycle. The eruption of Tambora coincided with another minimum in sunspot activity—the Dalton Minimum of 1790–1830. The Dalton Minimum was shorter and less intense than the Maunder Minimum, but it still resulted in a notable decrease in sunspot activity; hence the surprise exhibited by the appearance of a large sunspot in April 1816.