Across the world, scientists are trying to determine where seasons are shifting. Spring arriving earlier, winter arriving later — it’s happening in many countries. Now, the question is, what will be the consequences of that change
In a small park at Wageningen University, biologist Arnold van Vliet points out the signs of spring that are all around — a prunus tree, with nice white flowers, a hazel bush unfolding its leaves.
It’s a lovely sight on a beautiful spring day. The only problem is that these flowers and leaves really shouldn’t be here in the Netherlands yet.
“Everything is now two to three weeks ahead of schedule,” van Vliet said. “Butterflies are appearing very early — extremely early because of the very warm March we had.”
But a warm March here isn’t that much of an anomaly these days. Van Vliet said spring is regularly coming weeks earlier than it used to in the Netherlands. In fact, he said, with temperatures on the rise the whole climate of the country has shifted in the past 10 years to become more like southern France.
Van Vliet has been following this climatic shift for more than a decade as head of an effort here called “Nature’s Calendar.” The program enlists the help of more than 8,000 scientists and ordinary Dutch citizens to track changes in the seasons through what’s known as phenology. That’s an old-fashioned word for the study of the timing of seasonal, life-cycle events, such as the first flowering of a particular plant, or when a species of bird first lays its eggs in spring.
People who work close to nature have been tracking this kind of data for centuries. But environmental scientists in the Netherlands and elsewhere are more concerned about it than ever, because the shifting of the seasons is having real environmental effects.
“We see that the length of our growing season is already one month longer than before 1988, when the temperature started to change,” van Vliet said. “We see already an enormous change in species diversity in the Netherlands—very many southern species that live in Belgium, France and even farther south, that (now) appear in the Netherlands. And the more cold-loving species are significantly decreasing. So we see that signal.”
And the Dutch aren’t alone. As the planet warms up, scientists are seeing a similar trend around the world. Jake Weltzin, an ecologist with the US Geological Survey in Tucson, Ariz., and coordinator of the USA National Phenology Network, said spring has been coming earlier in much of the United States. …