In a Lowell, Mass., cemetery on Memorial Day 1868, a photograph captured mourners in heavy winter clothing gathered under leafless trees near the graves of two brothers killed in the Civil War.
At the same spot on Memorial Day 2005, cemetery visitors wore light spring clothes. The trees were in full flower.
These photographs are a close-to-home reminder of the effects of global warming, said Boston University biology professor Richard Primack and BU graduate student Abraham Miller-Rushing at a Feb. 21 Soap Box event, "Global Warming: Up Close and Local," at the MIT Museum.
Primack, an author of textbooks on conservation biology, said that in 1992, global warming received little more than a mention in his textbooks. It has since expanded into a whole section, and he became interested in how global warming is affecting species and how to detect the local signature of global warming.
Discussions on global warming mentioned the same studies over and over, and they were all in far-off places like Antarctica. "In Boston, we could do better," he said. Four years ago, with Miller-Rushing's help, he started gathering data from unlikely sources, such as the hobbyist who collected cemetery photos, on the timing of flowering plants, ribbeting frogs and migrating birds.
He found that all these things were happening earlier and earlier. Because of its heat-trapping buildings and parking lots, Boston and other urban areas warmed more than the rest of the country-2.5 degrees Celsius vs. 0.6 degrees elsewhere.
When co-dependent species become out of sync, it can cause species to decline and become extinct very rapidly. Birds who return after certain flowers have bloomed and insects have hatched could starve.
This science, the study of the timing of recurring natural phenomena, is called phenology. Primack and Miller-Rushing urged everyone attending the Soap Box to become amateur phenologists by recording the arrival of flowers, butterflies and dragonflies, and other seasonal events, and sending them to him. Many in the audience said they would be willing get involved.
The researchers have found data at the Arnold Arboretum, where plants have started flowering an average of eight days earlier over time; bird migration information recorded in Manomet, Mass.; a woman who kept precise outdoor records at her home for 50 years; naturalists' diaries and birdwatchers at Mt. Auburn Cemetery who seek to outdo each other by spotting the first wood thrush of the season. Even Thoreau's Concord, Mass., diaries with his painstaking observations of 600 species have been invaluable.
This information provides patterns that can help explain which species are most sensitive and which are least sensitive to climate change, so we can make predictions about the future, Primack said. "We'd like to create a map of how things are changing across New England.
"This is not about glaciers or extinct frogs in the mountaintops of Costa Rica," he said. "This is a way people can see for themselves that climate change is affecting the organisms living in our gardens and the birds visiting our bird feeders."
This Soap Box program will be part of the new Cambridge Science Festival to be held April 21-29.
To send nature observations, email firstname.lastname@example.org with "Nature's Calendar NE" in the subject line.