The Year Without Summer (6 page)

Timothy Dwight, a Massachusetts cleric and educator who, like his contemporary Jefferson,
loved to collect weather data, also rejected the argument that American winters were
growing milder. Dwight pointed to numerous very cold and snowy winters in the thirty
years since independence that rivaled any of the formidable seasons of the seventeenth
or early eighteenth centuries. Besides, discussions of changing climates seemed pointless
to Dwight without adequate statistical data. “Few, if any, registers were kept in
former times,” Dwight noted, and fewer still had been published. “Hence the comparisons
of our present climate with that of former periods must be extremely defective.”

Climate scientists now know that deforestation of large areas can cause prolonged
droughts and exaggerate seasonal variations in temperature, such that summers become
much warmer and winters much colder. Dunbar was partially correct in his conclusions,
although he failed to understand how forest canopies maintain the climate beneath
them. Forests insulate their environment not only by reflecting sunlight but also
by trapping moisture; plant roots help to retain water in the ground, while the canopy
prevents water vapor from escaping into the air above. Remove the forest, and the
moisture in the soil quickly escapes; winds then transport the water vapor hundreds
or thousands of miles away. This starts a vicious cycle: Less water in the soil leads
to less evaporation into the air, which can lead—when applied to an area of hundreds
of square miles or more—to less rainfall, which in turn leads to less water in the
soil. What rain does fall will often be unable to penetrate into the dry, hard soil,
further increasing the risk of devastating droughts.

Summers become hotter in deforested areas not only because more sunlight reaches the
surface, as Dunbar argued, but also because there is less moisture in the soil to
cool the ground through evaporation. Water in the soil performs the same function
as sweat does in humans; with little moisture to evaporate, bare ground quickly warms
in the sunlight. Without the insulating effects of the forest canopy, winter temperatures
can drop rapidly as the heat stored in the soil is lost to the atmosphere. There is
no evidence to support Dunbar’s link between deforestation and stronger northerly
winds, although generally forests do act as a brake on the local wind speeds, regardless
of the direction. The effects of deforestation on local temperatures and rainfall
can be mitigated where the forests are replaced with other ground cover, such as shrubs
or crops, instead of simply left as bare soil.

If deforestation had, in fact, transformed their climate, Americans were ambivalent
about the desirability of that change. On the one hand, the early colonists viewed
the virgin North American forests as dangerous and evil places, the preserve of the
devil (and, not coincidentally, Native Americans). They and their descendants believed
they had a duty to level what Nathaniel Hawthorne termed the “heathen wilderness.”
Turning a dense and dark forest filled with “stagnant air” and “rank vegetation” into
productive farmland to support a Christian community seemed to fulfill God’s plan
for the New World. Yet by the early nineteenth century, Americans in the Eastern states
increasingly viewed the landscape less as a threat than a source of beauty and natural
wonder. Alarmed at the ravages wrought by the “savage hand of cultivation,” they worried
that their slashing and burning of the wilderness despoiled God’s handiwork and disrupted
the natural harmony between heaven and earth, and that violent and erratic weather
patterns comprised their punishment.

Certainly, chauvinistic New Englanders who prided themselves on their hardiness had
no desire to escape the bracing rigor of their winters. Months of subfreezing temperatures
accompanied by occasional blizzards built the rugged New England character, they believed,
inculcating the virtues of prudence, foresight, diligence, and cooperation in farmers
from Connecticut to Maine. “Of all the scenes which this climate offers,” wrote St.
John de Crevecoeur in an essay on the American farmer, “none has struck me with a
greater degree of admiration than the ushering in of our winters … a rigour which,
when once descended, becomes one of the principal favors and blessings this climate
has to boast of.” Without such a challenge, New Englanders feared losing their unique
identity and growing as weak and soft as they perceived the European character.

Popular anxiety about a general warming trend faded, however, as the nation entered
the second decade of the nineteenth century, the coldest ten-year period on record
in the history of North America. Even before the eruption of Mount Tambora, aerosol
veils from a series of volcanic eruptions were cooling temperatures around the world.
In 1809, a very powerful volcano erupted at an unidentified location—probably somewhere
in the tropics, based on the recent discovery of large amounts of volcanic sulfuric
acid in ice cores in the Arctic. Three years later, Soufrière (“Sulfur Mine”) on Saint
Vincent erupted over a six-week period, followed by Awu on Sangihe Island, slightly
northeast of Tambora. In February 1814, the eruption of Mount Mayon in the Philippines
killed over 2,000 people on the island of Luzon. Some of each of these aerosol clouds,
particularly the latter two, would have lingered in the stratosphere in 1815. (The
lifetimes of stratospheric clouds vary from eruption to eruption, but three- to five-year
spans are common, with a decreasing fraction of the original cloud remaining each
year.) The devastating global cooling from Tambora, an eruption more powerful than
the three earlier ones put together, was likely amplified by the existing cooling
trend from these previous eruptions.

In the United States, 1812 brought significantly cooler temperatures and greater precipitation
than usual; at Middlebury College in Vermont, Professor Frederick Hall noted that
“crops were destroyed by the coldness and wetness of the season,” and observers in
New England reported frosts in late August and snow in September. The following two
years were only slightly colder than normal, but the growing season of 1815 in New
England was cut short by May snows and early September killing frosts. In eastern
Canada, the province of Quebec suffered devastating losses to its harvests in 1815.
The relatively mild North American winter of 1815–16, therefore, generated few complaints.

Then April arrived. After a mild start, the weather took a decidedly nasty turn in
the middle of the month. On April 12, nearly a foot of snow fell on Quebec City, and
it continued to snow for the next five days. “The country has all the appearance of
the middle of winter,” noted a news report on April 18, “the depth of snow being still
between 3 and 4 feet. We understand that in many parishes the cattle are already suffering
from a scarcity of forage.” The same storm hit Albany, New York, a day later, leaving
the roofs of houses and the nearby hills completely covered with snow. To the west
of the city, “the country in many places had the appearance of winter; the hills being
as white as in the month of January.” Further west, the storm surprised settlers in
the town of Chillicothe, then the capital of Ohio. On April 18, one correspondent
reported “a temperature extraordinary at this season of the year. In the latter part
of last week, the weather was excessively cold—on Sunday, snow fell to the depth of
several inches; and since that time the weather has been clear, but nearly as cold
as it was in February.”

But the advent of a heat wave at the end of the month raised farmers’ spirits; by
the time the sunspots appeared in late April, Vermont farmers—who already had planted
some of their crops—were sweltering under highs in the low 80s.

*   *   *

C
OOLER
temperatures also settled across the European continent in 1810, ushering in a decade
that would be the coldest in several centuries for much of western and central Europe.
From 1810–1815, the difference was felt mainly during the autumns and winters; the
summers were not unusually frigid. In 1812, central Italy experienced snow and a highly
atypical hard freeze in April, followed by a very cold autumn; harvests in Germany,
Switzerland, and the Netherlands also suffered from the cold. After relatively normal
weather in 1813, exceptionally low temperatures returned in 1814—the coldest year
on record for much of central Europe. Conditions did not improve significantly in
1815: Switzerland, Italy, Germany, and Austria (especially in the southern provinces
of Styria and Carinthia) all endured heavy precipitation and a colder than usual autumn,
resulting in poor harvests which sent the price of wheat sharply higher. Weather during
the winter of 1815–16 was unsettled across much of Europe; in Germany, strong winds
and a lack of snow cover blew wheat seeds off the soil, forcing farmers to replant
their fields.

In Britain, 1810 marked the start of the coldest decade in Great Britain since the
1690s, with average temperatures one to two degrees Celcius colder than normal, frigid
enough to provoke a change in women’s fashions. During the 1790s, English women had
adopted revealing styles of undergarments from France; as temperatures dropped, however,
they covered up their cleavage with the more modest and far warmer shifts known as
“bosom friends” to help fend off the chilling winds.

Despite the cooler weather, British farmers enjoyed a very good harvest in the autumn
of 1815. The following winter began colder than usual in Britain, with highs in the
upper 30s and low 40s in January and February. March brought spells of warmer weather,
but significantly more precipitation; it snowed or rained for nearly half the days,
and one storm dropped a foot of snow on Lancashire. Sleet and snow returned on April
9, along with subfreezing temperatures that kept several inches of snow on the ground
in southern England. Four days later, heavy snow along the east coast prevented travelers
from leaving Dover for the continent; more snow fell on April 14. By the last week
in April, highs were back in the mid 60s, and farmers could finally plant their crops,
but the growing season already had been delayed. In Ireland, too, the spring was abnormally
late.

Scotland fared worse. In Aberdeenshire, frost and snow from mid-November through mid-March
froze the turnips used for cattle fodder, and the plants rotted in the alternating
frosts and snow. “We never experienced a worse winter for feeding,” complained the
Aberdeen
Journal
. Farmers began taking their cattle to market much earlier than usual, driving down
the price of beef. The remainder of March in eastern Scotland was “stormy in the extreme;
in consequence of which … very little ploughing was got done.” April was cold and
dry. Virtually nothing was growing by the beginning of May: “Even on the coast, there
is yet no appearance of vegetation.” Conditions improved little in May. “Throughout
the whole of this month,” noted a report from Midlothian, just south of Edinburgh,
“the weather has been unusually barren, from a continued cold, sharp, dry wind, generally
from the north.… The fields, in general, are backward and in great want of warm sun,
especially the grass and wheat, which is near a month later than ordinary, and are
weak and unpromising at present.”

Across most of western and central Europe, spring was lost in the waves of cold weather
that swept over the continent in April and May. Travelers to Calais in mid-April encountered
a storm that brought “a considerable quantity of snow” to northern France. In the
Abruzzo region of central Italy, farms in the higher elevations still had so much
snow on the ground in late May that farmers could not sow their wheat, and the price
of grain was rising. There were late frosts in Austria, and the stormy winter and
cold spring already had created a shortage of grain and higher prices in southwestern
Germany, as well.

On May 12, sleet pelted English fields and towns. “Never was there such a backward
season,” muttered the English reformer and part-time farmer William Cobbett. “The
extreme changeableness of the weather which has prevailed so long, still continues,”
reported the
Royal Cornwall
Gazette.
“Every flattering prospect of genial warmth has been quickly succeeded throughout
the spring, with the reverse of a chilling and searching, or damp atmosphere.” Particularly
in northern England, oats had “a yellow and unhealthy appearance,” and wheat looked
so sickly that many farmers simply ploughed up their fields and resowed their lands
with barley. Pastures and meadows seemed barren and backward. “Such an ungenial season
has necessarily been unfavorable to all the production of the earth,” concluded the
Gazette
, “giving the assurance of a late harvest, so full of risk and experience in the northern
parts.”

This news did not please Lord Liverpool, the prime minister, an unimaginative, no-nonsense
Tory who had led His Majesty’s Government since the assassination of his predecessor,
Spencer Perceval, in 1812. “Led” perhaps was too strong a word; Liverpool, whom Benjamin
Disraeli later referred to as “the arch-mediocrity,” was the titular head only of
the Conservative Party. His subordinates, including Foreign Secretary Lord Castlereagh,
regularly took turns usurping his authority.

Royal authority was exercised in 1816 by the Prince Regent, the eldest son of King
George III, although the king was still alive. Beginning with a brief attack in 1765,
George III experienced periodic bouts of madness that appear to have been the result
of porphyria, a rare blood disorder. His symptoms included delusions, hallucinations,
severe abdominal pains, insomnia, confusion, and muscular weakness. His physicians’
inability to determine the cause of his illness, and their understandable reluctance
to hazard a guess about the likelihood of any recovery, had contributed to a constitutional
crisis when the king suffered a second, prolonged attack in 1788. Parliament waited
more than six months for George to recover; finally the House of Commons passed a
Regency Act to transfer authority to the Prince of Wales. But as the Lords debated
the measure, the king suddenly and unexpectedly recovered, and remained in good health
until the next attack in 1801. A fifth and final attack in 1810 convinced parliamentary
leaders to approve another measure to permit the Prince of Wales to rule in place
of the seventy-two-year-old monarch, although fleeting glimpses of sanity in the first
year or two kept alive hopes of the king’s eventual recovery.