Our fickle New England weather often appears in daily discourse. When boasting about having endured one meteorological extreme or another, we sometimes stretch the limits of our credibility. One old-timer is reported to have buttonholed his neighbor with, “Last winter, the temperature outside my window dropped 50° in a 12-hour period!”
To which the neighbor replied, “Yup, I used to have a thermometer just like that.”
Yankee hardiness aside, global climate change is influencing our already-tempestuous atmosphere. But how can we tell the difference between the normal ups-and-downs of local weather and the abnormal effects of global warming, especially when our “normal” weather already fluctuates markedly?
Short of becoming climate scientists, one way for each of us to track climate change is to observe and carefully record how plants and animals respond to the seasons over time. When do the red-winged blackbirds return in the springtime? What date marks the first run of maple sap? How soon do the lilacs bloom? On which autumn morning will we discover the first glistening frost of the season?
Keeping track of natural events and cycles is called phenology – a word that comes from the Greek phainestain, “to appear,” and logos, “study.” You can become a phenologist simply by maintaining a detailed record of how temperature, light, and precipitation affect the life cycles of local plants and animals from year to year.
Some famous phenologists include Carl Linnaeus, Henry David Thoreau, John Muir, and Aldo Leopold. Thoreau created a detailed calendar of events for the natural history of Concord, Massachusetts. He charted the progress of plants and animals through the seasons during a 10-year period that ended in 1861, including the dates when birds returned in the springtime, when insects hatched, and when flowers bloomed and leaf buds unfurled.
In his landmark book on conservation, A Sand County Almanac, Aldo Leopold chronicled the natural world over time. Between 1935 and 1945 he carefully recorded 145 annual natural events in Madison, Wisconsin – work that is still being carried on by his descendants. Leopold once noted that, “In June as many as a dozen species may burst their buds on a single day.”
I confess to being an intermittent phenologist. One of the lists I’ve kept includes dates for when the first hummingbirds appear at our Vermont feeders: 5/28/92 and 5/29/93 (South Pomfret); 5/22/95, 5/13/96, 5/13/97 and 5/15/98 (Union Village); and 5/8/03, 5/11/04, 5/15/05 and 5/7/07 (Chester). While this record is incomplete and varies geographically, it does show how consistent hummingbird arrivals can be in any one location, and it documents that hummingbirds arrive later in the northern and higher elevations.
Knowledge of the timing of natural events is crucial for nursery growers, farmers, gardeners, and others who rely on seasonal events for maple sugaring, leaf peeping, or skiing. Consistent natural history records are invaluable for tracking the health of ecosystems, changes in populations, and the distribution patterns of plants and animals. Information about insect hatches can help experts monitor and predict the steady march northward of threats to public health such as West Nile virus (mosquitoes) and Lyme disease (deer ticks).
In our society, where people move an average of every five years, it is difficult to amass a meaningful body of natural history observations through time. But a new effort is underway to make every observation count by having individual citizens enter their data into an online database called the USA National Phenology Network. (Visit the site at www.uwm.edu/Dept/Geography/npn/index.html.)
The next time the season begins to turn, you can use it as an opportunity to contribute to the collective understanding of how the natural world, influenced by human activities, is changing over time. Simply choose the aspects of plant and animal life that truly interest you and keep detailed, timely annual accounts. Lilac flowers, for example, are an excellent indicator. Following exposure to an essential period of winter chill, lilacs respond by blooming in a very predictable way to the warming season.
Observations are best if recorded in the same place each year by the same individual, since this allows for the most meaningful comparisons through time. If enough people keep accurate journals of natural events in their own backyards – including dates and observations – this new national database will create a picture of nature’s seasonal changes across the continent. This will provide scientists with vital information for studying global climate change and shifts in local weather.
Over the years, I’ve developed an appreciation for how our neighbors in the natural world can endure the ever-increasing extremes of seasonal weather in the North Country. Mark Twain got it right when he described New England weather: “There is only one thing certain about it; you are certain there is going to be plenty of it.”