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.