This book is available free on the Web, compiled by the Union of Concerned Scientists in 2009:

Thoreau’s Legacy: American Stories about Global Warming introduces a new generation of writers and photographers with a personal connection to global warming. The 67 essays and images in this anthology are drawn from nearly 1,000 submissions about beloved places, people, plants, animals, and activities at risk from a changing climate—and the efforts that individuals are making to save what they love. A foreword by author Barbara Kingsolver serves as a powerful call to action.
The essays we selected represent a variety of perspectives, voices, and experiences. The authors follow in the long tradition of great American environmental writers, like Henry David Thoreau, who have broadened our awareness and sharpened our perspective about the world we share. And they are inspiring action to protect our planet from global warming. They are Thoreau’s legacy.

Source: Email from Union of Concerned Scientists [action@ucsusa.org] June 22, 2009.