Climate Played a Role in the American Revolution
On April 19, 1775, the Battle of Lexington and
Concord broke out, and the "shot heard around the world" started America's
Two months later, New England farmers faced yet another killing frost,
which forced them to replant and use up precious seed that should have
been saved for the next season.
The causes of the Revolutionary War cited in textbooks--disputes over
taxes and what Americans perceived as British tyranny--remain accurate.
But a recently published study of climate history has added another: For
most of the 37 years preceding the war, harvests were below average or
Climatologist William R. Baron, of Northern Arizona State University,
and American Historian David Smith, of the University of Maine, are not
claiming that people were starving. Rather, their 20 years of research,
which received NSF funding in the late 1970s and early 1980s, shows that
the agrarian society was strapped for cash and luxuries, and therefore
less tolerant of the British attempts to tax the colony.
"Put yourself in the position of these people," suggests Baron. "Most
of them were farmers. They needed 80 percent of their crops to feed their
families, and the rest they expected to trade with merchants. The crop
failures ate up the extra 10, 15 and 20 percent of their crops."
Baron and Smith's project analyzed New England's climate from about 1700
to 1950, the time before meteorological science became widely used. They
read the farmers' records in the form of thousands of diaries and farm
journals, and analyzed newspapers and records from the few existing weather-stations.
With these records, Baron and Smith documented the widely varying growing
seasons of New England.
The record keepers were not necessarily professional scientific observers,
notes Baron in the introduction to his publication. "They made up for
their lack of scientific sophistication with a thoroughness of description
that allows us, in this century, to fully understand that 'September 3rd,
a severe black frost that laid low all of our vines, corn and potatoes
will make a hungry winter for us' meant a killing frost in early fall." The
researchers' work was published in a Maine Agricultural and Forest Experiment
Station Bulletin, titled Growing Season Parameter Reconstructions for
New England Using Killing Frost Records, 1697-1947.
The team found that, compared with mean temperatures for the entire century,
southern New England was cool during the period of 1740 to 1776. In the
1750s and 1760s, the temperatures were so cold that Indian corn did not
The years also alternated between wet and dry, and had fluctuating growing
seasons. In growing seasons from 1740 to 1776, eastern Massachusetts farmers
were stopped 17 times by late spring or early fall frosts.
With all of these climate fluctuations, the resulting harvests were often
Baron emphasizes that the years of poor crops did not cause the Revolutionary
War, but were likely to have added to overall discontentment. "When looking
at history, we cannot 'remove ourselves from the physical environment," he
says. "The environment definitely contributed to it."