Bad News from Walden Pond

Global Warming is changing Walden's famed pond.

• Hannah Schardt
• Dec 01, 2008

SOME CLUES to the future of global warming may be found in the past, according to new findings by researchers at Harvard University and Boston University (see "Walden Warming," October/November 2007). In an ongoing study of the Massachusetts fields, forests and wetlands where Henry David Thoreau once walked and kept careful inventories of the natural world, including the life cycles of plants, scientists have been comparing notes with the naturalist and writer. Their latest findings: For many plants, the news isn't good. A rapid rise in temperature--2.4 degrees C in the past century--has led to dramatic changes in the timing of flowering and other seasonal activities. This has left some closely related groups of species, including orchids, dogwoods, lilies and sunflowers, more susceptible to dramatic declines than others.

The study's authors conclude that climate-related loss of local plant diversity has been so significant--even in the mostly protected wilderness around Concord--that a global approach, not merely local conservation efforts, is required to stave off further declines.--Hannah Schardt