Climate Change in Concord

Concord, climate change, and Earth Week at Middlesex all came together during morning Assembly on April 21, when Richard Primack, professor of biology at Boston University, shared his current research with the school community.

Professor Primack is investigating the impact of climate change on the flowering and leafing out times of plants, the spring arrival of birds, and the flight times of insects in Massachusetts, Japan, and South Korea. Surprising to many in the audience was the fact that his main geographical focus in Massachusetts is Concord, due to the availability of extensive phenological records kept by Henry David Thoreau and later naturalists.

In 2002, while reviewing the latest edition of a textbook he had worked on, Professor Primack realized that some of the “theoretical” examples of global climate change had indeed become realities, such as the shrinking polar ice caps and disappearing tropical rainforests. At the same time, he wondered why there were no illustrative examples in the book from the Eastern United States and decided to search for some in the Boston area. After all, over the past 160 years of recorded temperatures for the months of March and April, Boston has warmed 2°C (4°F) – a bigger change than in the rest of the country, which has warmed an average of 1.5°C.

Just how this warming trend may have affected Boston’s environment, he proposed, could be determined by looking at old records detailing when springtime foliage and flowers used to appear. As Professor Primack soon learned, Henry David Thoreau kept just these kinds of records, documenting the flowering of plants and flowers – and the arrival times of birds – in Concord from 1851 to 1858. Deciphering Thoreau’s handwriting and terminology “took years,” but Professor Primack called the records “a goldmine for scientists,” providing plenty of information to compare with more recent data.

For the last 13 years, the Middlesex campus has been one of Professor Primack’s frequently visited field sites, as it was for Thoreau. On average, plants are flowering about four days earlier now than in the 1850s, and 27% of Concord’s wildflowers are no longer present, particularly species that thrive in colder climes. Birds are arriving in the area a couple of days earlier, too – not as significant a difference, but a trend that bears watching. Missing from the historic data is information about the insect world, which is unfortunate given that butterflies and bees are especially sensitive to changes in temperature.

“If the warming trend continues,” Professor Primack predicted, “Massachusetts’ climate could be more like North Carolina by the end of this century.” While many people are not convinced that any action needs to be taken now, he imagines that Thoreau, if he were alive today, would consider climate change an important cause. “It is important that you get involved,” Professor Primack stressed. “This is an issue of your time.”