Early American Scientists and Anthropogenic Climate Change

On Tuesday, 10 October, the Massachusetts Historical Society will host a session of the Boston Environmental History Seminar series.

James Rice of Tufts University will present a paper on “Early Environmental Histories,” and Chris Parsons of Northeastern University will comment on it. The seminar description says:

This essay speaks to questions raised in a recent workshop at the Huntington on early American environmental history. How do timespan and scale change our understanding of historical relationships between people and their environments? What new light does environmental history shed on topics such as race, gender, or law? What can early Americanists contribute to the field of environmental history as a whole?

That discussion will start at 5:15 P.M. Sandwiches will be available after the formal discussion. Reserve a seat in advance through the seminar series webpage.

I’ve been thinking about how some of the more scientifically minded Americans of the eighteenth century conceived of environmental change. They had no difficulty with the concept that human activity could affect the climate. Indeed, they might have been too optimistic about that possibility.

Many Americans of that period were anxious to refute the European perception that North America’s climate was too extreme—too cold in winter and too hot in summer—to be healthy. Winter was changing, they declared, as the European population spread. For example, the Rev. Cotton Mather wrote in The Christian Philosopher in 1721:

our Cold is much moderated since the opening and clearing of our Woods, and the Winds do not blow such Razours, as in the Days of our Fathers, when Water, cast up into the Air, would commonly be turned into Ice e’er it came to the Ground.

Benjamin Franklin was more scientific in his approach, telling the Rev. Dr. Ezra Stiles in 1763 that Mather’s belief needed to be tested with systematic measurements over a range of time and space:

I doubt with you, that Observations have not been made with sufficient Accuracy, to ascertain the Truth of the common Opinion, that the Winters in America are grown milder; and yet I cannot but think that in time they may be so. Snow lying on the Earth must contribute to cool and keep cold the Wind blowing over it. When a Country is clear’d of Woods, the Sun acts more strongly on the Face of the Earth. It warms the Earth more before Snows fall, and small Snows may often be soon melted by that Warmth. It melts great Snows sooner than they could be melted if they were shaded by the Trees. And when the Snows are gone, the Air moving over the Earth is not so much chilled; &c. But whether enough of the Country is yet cleared to produce any sensible Effect, may yet be a Question: And I think it would require a regular and steady Course of Observations on a Number of Winters in the different Parts of the Country you mention, to obtain full Satisfaction on the Point.

Mather, Franklin, and their contemporaries inherited the seventeenth-century Scientific Revolution, but their view of time and space were still limited. Scientists of the nineteenth century made the crucial breakthrough of conceiving of Earth’s age in millions and then billions of years, not just thousands. We have the benefit of a much broader perspective and a whole lot more data. The seminar at the Massachusetts Historical Society asks what the more detailed environmental insights we have today can tell us about Mather and Franklin’s time.