On Earth Day 2013, I'd like to draw your notice to a fantastic essay by Andrea Wulf in The New York Times Book Review. Wulf explains how information recorded by Henry David Thoreau in his journals is now informing modern climate-change research.
In journal passages, some of which formed the basis for his famous treatise Walden, Thoreau carefully recorded the blooming dates for hundreds of plants in the area around Concord, Mass., from 1852 to 1861. Now, a team of scientists led by Richard Primack of Boston University is comparing those historical dates with the dates that these same plants flower today.
The average date of spring flowering is now 11 days earlier than it was in Thoreau's time. Wulf writes:
Primack and his associates have determined that plants in Concord are reacting to warming temperatures by flowering roughly two days earlier for each degree increase in temperature.
Thoreau is considered by many to be the world's first environmentalist. One hundred and fifty years later, as climate-change science becomes ever more vital, his impact on our thinking is still immense.