Deforestation, Land Use, and Climate in Colonial America: Lessons from America's First Climate Change Debate

Anthropogenic climate change has been part of the American lexicon since the first Europeans explored the continental shores over five centuries ago. As colonial settlers cleared forested land, a heated debate arose about whether forest clearing was altering climate. Leading colonial intellectuals argued the merits and evidence that deforestation was improving the climate. The prevailing opinion was that deforestation was ameliorating the cold winter temperatures and oppressive summer humidity and reducing rainfall. The vast deforestation throughout eastern North America subsequently gave rise to a forest preservation movement, and conservationists carried the debate into the mid-1800s, but advocating the climate benefits of forests, particularly afforestation of the arid western lands to promote rainfall. Meteorologists strongly refuted the doctrine of forest influences on climate, and the study of forest-climate interactions receded from scientific inquiry into a narrow field of forest meteorology. It was not until the 1970s with the advent of atmospheric numerical models that study of the broad, regional climatic effects of deforestation, cultivation, and overgrazing reemerged. The writings of forests, land use, and climate change in colonial America have been told in many forms. Some argued that this was a misstep in the birth of meteorology as a quantitative science. Others have drawn parallels with public skepticism of global warming, suggesting that the science of climate change, like the early views on deforestation and climate, is poorly understood. An alternative interpretation is that the debate anticipated our modern understanding of climate - one in which climate depends on forests, grasslands, and other ecosystems and in which climate changes with human uses of those ecosystems. It was a first step in developing a broad understanding of the interdisciplinary aspects of climate and anthropogenic climate change. However, the harsh rhetoric of the era is evidence of the difficulties in communicating across multiple disciplines. Similar obstacles exist today as climate science has expanded to consider physical, chemical, biological, and socioeconomic processes in the Earth system.