Scientists Use Thoreau's Journal Notes to Track Climate Change
Researchers use "Walden" author's tables of flowering dates in 1840s Massachusetts to show temperature has risen 2.4 C.
Fittingly for a man seen as the first environmentalist, Henry David Thoreau, who described his isolated life in 1840s Massachusetts in the classic of American literature Walden, is now helping scientists pin down the impacts of climate change.
The American author, who died in 1862, is best known for his account of the two years he spent living in a one-room wooden cabin near Walden Pond "because I wished to live deliberately, to front only the essential facts of life." Packed with descriptions of the natural world he loved, Walden is partly autobiographical, partly a manifesto for Thoreau's belief in the rightness of living close to nature. "I never found the companion that was so companionable as solitude," he writes. "Simplify, simplify."
But Thoreau was also a naturalist, and he meticulously observed the first flowering dates for over 500 species of wildflowers in Concord, Massachusetts, between 1851 and 1858, recording them in a set of tables. When Richard Primack, a biology professor at Boston University, and fellow researcher Abraham Miller-Rushing discovered Thoreau's unpublished records, they immediately realized how useful they would be for pinning down the impact of the changing climate over the last century and a half. The timing of seasonal events such as flowering dates is known as phenology, and the phenologies of plants in a temperate climate such as that of Massachusetts are very sensitive to temperature, say the scientists. Studying phenology is therefore a good indicator of ecological responses to climate change.
"We had been searching for historical records for about six months when we learned about Thoreau's plant observations. We knew right away that they would be incredibly useful for climate change research because they were from 150 years ago, there were so many species included, and they were gathered by Thoreau, who is so famous in the United States for his book Walden," said Primack. "The records were surprisingly easy to locate once we were aware of them. A copy was given to us by an independent research scholar, who knew that they would be valuable for climate change research."