Signs of an Unusually Early Spring in Southeastern Pennsylvania Should Not Be a Cause for Celebration
I decided to look around for more signs of an unusual outbreak of Spring, and was quickly rewarded by a magnolia tree full of fuzzy swollen buds that could well start to flower by week's end and, looking up at a tall silver maple nearby, by the sight of bursting green flowers covering the small branches at the top of the tree.
In general, such signs of Spring bursting out are welcome at the end of a harsh cold winter, but the truth is, this has not been a harsh winter. We only had two snowfalls, both relatively minor, and the prospect of any more is pretty slim at this point, with no snow in the forecast for the next two weeks, and by then we're less than two weeks away from the official start of Spring. Temperatures in the northeastern US, as in much of the country, have been setting records for winter highs which explains the plants getting an early start. It's a continuation, as the linked article above shows, of a trend that has been underway for some years now.
Climate change deniers, a dwindling group, will no doubt start changing their tune, since the evidence of dramatic warming is getting impossible to ignore. Increasingly, their line is to ask, "So what's wrong with things getting warmer? That means a longer growing season, lower heating bills, and no need for jackets and sweaters."
The problem though, is that while we humans are an adaptable species, plants and the rest of the ecosystem (upon which we ultimately depend for food and for the very oxygen we breathe), aren't really ready for this. One big threat is that those plants that pop out of the ground too soon, or that open their protective buds too early, can fall victim to another impact of climate change: the extreme warming of the Arctic and the melting away of the ice sheet over the Arctic Ocean. That warming, by reducing the gradient of hot and cold between the northern hemisphere's arctic and temperate zones produces a wildly wobbling if weakened Jet Stream, which is wont to drop down suddenly and unpredictably for a week or so over the Lower 48, bringing with it much colder temperatures which can then kill off the early blooming plants.
Last year, this happened in the northeast, devastating the apple crop in Pennsylvania, New York and New England, where the apple blossoms were out almost four weeks early. Our two apple trees had exactly no apples last year as a result. The same thing could easily happen again this year.