It's officially spring, and even if it doesn't seem like it on the East Coast, soon enough flowers will start blooming earlier than ever. Beginning in 1851, the writer and naturalist Henry David Thoreau began diligently recording the spring bloom dates in Concord, Massachusetts, and for the past decade, Boston University’s Richard B. Primack has done the same. And, by comparing the numbers, Primack and his team found that, on average, flowers are blooming ten days earlier than they were in Thoreau’s time.
There's a simple reason: In the 150 years between Thoreau’s observations and Primack’s, Concord’s average temperature rose by more than four degrees Fahrenheit. We recently spoke with Primack, a professor of biology who studies the impact of climate change on plants and animals, about what spring will look like in the future, and his answers weren’t pretty.
What things that we think of as characteristic of spring will be different in the future?
A lot of things are changing, but it depends on where you are. I’m in Boston. The climate is getting warmer all across the eastern U.S., so the things I experienced growing up in Boston in the '50s and '60s are gone. The climate of Massachusetts now is like what the climate of New York City was when I was growing up. This trend will continue. In coming decades, the climate of Massachusetts will be like the climate of New York City now.
So what specific changes can we expect?
Trees will be leafing out earlier in the spring. When snow melts on the ground and ponds thaw out will keep getting earlier. Birds are going to stay later into autumn. Leaves will be falling off trees later in the year.
Not all of that sounds so bad. What’s the downside of an earlier spring?
From a biological perspective, if there are shorter winters, there are more likely to be outbreaks of insects, because populations are often controlled by cold weather. A lot of endangered species are in wetlands, and as temperatures get warmer, it’s likely a lot of these wetland areas will start drying out.
Then there are some really negative consequences for people as temperatures warm. The biggest of all is that as conditions get warmer, sea levels are going to rise and, increasingly, hurricanes are going to create extremely damaging flooding. A few years ago, Hurricane Sandy hit New York and New Jersey and put the subway system underwater. These kinds of extreme flooding events become more likely as the sea levels begin to rise.
If spring starts earlier and the warm season is longer, does that mean allergies will be worse?
That’s possible. The pollen season will definitely be earlier. The autumn pollen season of grass and ragweed will almost certainly be longer. Ragweed and grass pollen season usually ends by the first frost, but because of climate change, we’ll probably have a longer pollen season at the end of the year.
Longer spring means shorter winter. Why's that a problem?
Because of warming temperatures, often in the winter you have precipitation falling as rain rather than snow, so there’s less snow cover. Trees in New Hampshire and Massachusetts are adapted to a long snow cover. If the ground is exposed, then when we do have severe cold the ground freezes much more solidly, and you have a lot of frost damage to the roots of trees. That could kill a lot of tree roots and results in the release of more nitrogen into the soil. This could result in an increased release of nitrogen in water, making it less clean.
What about spring can we expect to remain the same?
A lot of things we’re talking about are relatively subtle — the things that scientists detect with long-term measurements. The things that will be noticeable will be things like not being able to ice-skate where you used to go ice-skating.