Global Warming Changes Thoreau's Walden

While living at Walden Pond, Henry David Thoreau collected detailed data on the plant species native to Concord, Mass. Scientists studying climate change have compared those records to present-day biodiversity—and found chilling evidence of global warming’s effects, the Boston Globe reports. 27% of the species Thoreau documented are gone, and another 36% have been diminished to the brink of extinction.

Concord remains largely undeveloped since Thoreau’s time, but ambient temperatures have risen 4 degrees. Because that makes pollinating insects arrive earlier, species that reacted to the rising temperatures by flowering a week before the dates Thoreau recorded have survived, while those that didn’t have largely died off. “Climate change is throwing off the synchronicity of nature,” remarked one scientist.