Thoreau the climatologist

Thoreau is sometimes criticized for having spent too much of his later years in scientific speculation and in compiling tables of data about the plants and weather of Concord. Books like Faith in a Seed and Wild Fruits, edited and published posthumously, eventually made it clear that Thoreau needs to be taken seriously as a naturalist.

Now a new study draws on Thoreau’s data to show how the climate of Concord has changed in the last hundred years. (I first heard this story on NPR, where the scientist being interviewed admitted with some chagrin that he had never actually read all of Walden. My mother then let me know about the story in the Times.)

On average, common species are flowering seven days earlier than they did in Thoreau’s day, Richard B. Primack, a conservation biologist at Boston University, and Abraham J. Miller-Rushing, then his graduate student, reported this year in the journal Ecology. Working with Charles C. Davis, an evolutionary biologist at Harvard and two of his graduate students, they determined that 27 percent of the species documented by Thoreau have vanished from Concord and 36 percent are present in such small numbers that they probably will not survive for long.

According to the scientists, “there is growing evidence that as birds change their migration patterns in response to climate change, they may no longer be in sync with the insect species they feed on.” The flower pictured is an Indian paintbrush, one of those that has adapted poorly.