• Thu. Jun 13th, 2024

Thoreau: A Lesson in the Effects of Climate Change

ByAlkisti Kallinikou

Feb 11, 2023
Plastic bottle lying on bank of river

In 1845, scientist Henry David Thoreau embarked on what would be his twenty-six-month-long sojourn in a cabin near Walden Pond. Contrary to popular belief, his intention was not to isolate himself but rather, as he famously wrote, to “live deliberately, to front only the essential parts of life”.

Walden, or Life in the Woods is the most eminent product of that adventure. The text has not only become an exemplar of American literature, but it has since been the departure point for many naturalists and environmentalists following in Thoreau’s footsteps. 

Walden has, undoubtedly, much to offer to many different types of readers. What is, perhaps, less well-known is that Thoreau also kept elaborate diaries for many years, in which he documented his percipient observations of the world and reported on the surrounding environment, flora, and fauna. His notes are replete with fascinating and meticulous details on plant life, including the appearance of leaves and buds, blooming, as well as the coming and going of birds.

Almost 160 years later, a team of researchers from Boston University led by Biology professor Richard Primack initiated a study on the timing of seasonal changes, aiming to examine the effects of anthropogenic climate warming on the lives of plants and ecosystems in general. Their research site was Concord, Massachusetts, the same place where Thoreau lived and worked. Primack’s group began by studying certain spring events, such as the flowering of plants or the arrival of birds. Soon thereafter, however, they encountered unpublished data from Thoreau’s field notes with thorough records on the appearance of leaves that captured their interest.

In a paper published in April 2016, the researchers claim they were not expecting to find significant changes in the leaf-out times they had started studying. So, the results came as a surprise: after monitoring more than 40 species for five years, they found that plants leafed approximately 18 days earlier than those of the same species Thoreau had observed. 

In other words, on average, plants leaf out five days earlier for each 1-degree Celsius increase in temperature. Warming temperature is what gives plants the signal to produce leaves or buds. The same research has found that the greater Boston area where Concord is located has become almost 3 degrees Celsius warmer than Thoreau’s days. Therefore, when the weather warms earlier, plants’ functions follow. Yet, other creatures and beings that rely on this flora for nourishment do not exhibit the same behaviour. Take young caterpillars, for example. Their diet primarily consists of leaves.  For them, leaf-out timing drastically determines whether they will be eating soft, young leaves or sturdier, older ones. Followingly, migratory birds that arrive will need to feed on the insects in turn. It slowly becomes clear how one species is dependent on the other for survival and how such seemingly small changes end up affecting entire ecosystems.

In another of his works, the essay “Walking”, Thoreau expresses his desire to “speak a word for Nature […] to make an extreme statement, […] an emphatic one”, and his words successfully resonate and find new uses after all this time. Boston University’s Concord study demonstrates that we need not look at remote places such as the polar regions to witness evidence of climate change. 

Moreover, it serves as an example of how citizen science can significantly contribute to the work of scientists. Besides a genuine interest and observation skills, no specialised knowledge or tools are required by most people to undertake activities similar to Thoreau’s. Plant and birdwatching, reforestation and planting, observing wildlife, and studying satellite images are only some examples of how everyday people can become involved. In addition to providing vital data for professionals, such activities can induce accountability and ultimately create better-informed, more caring citizens.

Thank God men cannot fly, and lay waste the sky as well as the earth. ~Henry David Thoreau” by katerha is licenced under CC BY 2.0.