Includes bibliographical references (pages 243-246) and index.

Borneo to Boston. We find Thoreau's records ; "A self-appointed inspector" ; On thin ice ; Ice at Walden Pond -- A hard rain. Nor'easters in New England ; What would Thoreau have done? -- Thoreau, scientist. Thoreau as a scientific observer ; Deciphering Thoreau's journals ; Decoding the data ; Our fieldwork begins -- Phantom plants. Revolutionary viewpoint ; "Terror" on the tracks ; Pink lady's slipper orchid : a sign of warmer times ; Mercury rising ; Thoreau's mantle passes to Hosmer ; Heat Islands ; Plants respond to temperature ; Timing matters ; Thoreau's records and today's climate -- Wild apples and other missing flowers. From common to rare to vanished ; Finding the missing wildflowers ; Vanishing orchids and missing mints ; Species loss and climate change in Concord ; Why do flexible species succeed? ; How fast is Concord losing species? ; Ray Angelo gets mad ; Did we forget about deer? -- The strife in loosestrife. The net loss of species ; The McGrath farm ; Any new species? ; Minot Pratt's introductions ; Taking action -- The message of the birds. Springtime bird arrivals ; Finding bird arrival data ; Thoreau's birds ; Modern records ; How good are the data? ; What do the bird data show? ; Climate change and many other factors -- Birds in the mist (net). What the Manomet data showed ; How do changes in population size affect bird data? ; Birds and climate : what drives arrival times? ; A farm diary ; Earlier appearance of spring activity ; Putting it all together ; Feathered ghosts -- Bees and butterflies. The helpful honeybee ; The forgotten bees ; We shift to butterflies ; Sharon Stichter's butterfly data ; The great northward expansion ; The Massachusetts Butterfly Club ; Elfins and hairstreaks : a natural experiment -- From insects to fish to people. Warming water at Walden ; The value of fishing ; Margaret's approach to fishing ; Eating smaller fish and krill -- Clouds of mosquitoes. Mosquitoes and climate change research ; Mosquitoes and eastern equine encephalitis ; Catching mosquitoes ; Mosquitoes connect birds and people ; Spraying to control mosquitoes ; The importance of insects -- The frog chorus. Trouble for turtles ; Too dry or too wet : changing rainfall and amphibian life cycles ; Salamanders in eastern Massachusetts ; Salamanders in the Hammond Woods ; Salamanders at the golf course ; The future of amphibians in Concord's woods -- Running in the sun and rain. Athletic endeavor and climate change ; Does a warming climate affect the Boston Marathon? ; The other side of Heartbreak Hill -- A new Earth. An alternative future ; Is climate change really happening in Concord? ; The world is changing for the worse ; What do we need to do? ; Can Thoreau show us a better path? ; Living simply in Japan ; Thoreau's advice to modern Americans -- Citizen science. Getting started ; Joining with others ; My own journal -- Species mentioned. In his meticulous notes on the natural history of Concord, Massachusetts, Henry David Thoreau records the first open flowers of highbush blueberry on May 11, 1853. If he were to look for the first blueberry flowers in Concord today, mid-May would be too late. In the 160 years since Thoreau's writings, warming temperatures have pushed blueberry flowering three weeks earlier, and in 2012, following a winter and spring of record-breaking warmth, blueberries began flowering on April 1st., six weeks earlier than in Thoreau's time. The climate around Thoreau's beloved Walden Pond is changing, with visible ecological consequences. In this book teh author uses Thoreau and Walden, icons of the conservation movement, to track the effects of a warming climate on Concord's plants and animals. Under the attentive eyes of the author, the notes that Thoreau made years ago are transformed from charming observations into scientific data sets. The author finds that many wildflower species that Thoreau observed, including familiar groups such as irises, asters, and lilies,have declined in abundance or have disappeared from Concord. He also describes how warming temperatures have altered other aspects of Thoreau's Concord, from the dates when ice departs from Walden Pond in late winter, to the arrival of birds in the spring, to the populations of fish, salamanders, and butterflies that live in the woodlands, river meadows, and ponds. He demonstrates that climate change is already here, and it is affecting not just Walden Pond but many other places in Concord and the surrounding region. Although we need to continue pressuring our political leaders to take action, the author urges us each to heed the advice Thoreau offers in Walden: to "live simply and wisely." In the process, we can each minimize our own contributions to our warming climate.