A growing body of research shows that climate change is throwing the seasons out of whack.

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At a crowded town square in western Pennsylvania on Feb. 2, the world’s most famous groundhog — Punxsutawney Phil — did not cast a shadow, which legends say indicated that spring should arrive early this year. 

While the groundhog has been known to give notoriously inaccurate forecasts, this one probably wasn’t too far off base. As climate change accelerates, the signs of spring are arriving earlier in many parts of the world, from unnatural warmth to the tell-tale throat itch that accompanies seasonal allergies. 

The federally funded National Phenology Network — a group the monitors the biological impacts of seasonal changes — tracks when plants sprout leaves across the U.S., and says on its website that spring conditions in “Des Moines, Iowa, is 20 days early, Detroit, Michigan, is 23 days early, and Cleveland, Ohio, is 16 days early compared to a long-term average of 1991-2020.”

Research has detailed the many ways that this early spring trend could throw plants, animals and seasonal pastimes out of whack. As last week marked the actual first day of spring, I thought I’d point out some of the impacts of these early seasonal shifts that scientists have documented in the past few years. 

Early-blooming blossoms: 

Starting around the end of each March, tourists flock to cities across Japan and the Tidal Basin of Washington, D.C., to see the same thing: blooming cherry blossom trees. The vibrant petals transform the trees into clouds of pink, but these cotton-candy flowers have been blooming earlier in the past few decades, research shows. 

In Japan, the average start date of blooming has begun 1.2 days earlier per decade since 1953, Daisuke Sasano, a climate risk management officer at the Japan Meteorological Agency, told Bloomberg

“Spring warming is the most important determinant of flowering times for cherry trees,” Richard B. Primack, a researcher and professor of biology at Boston University, told BBC News. “And because spring weather is getting warmer, cherry trees are flowering earlier.”

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A similar trend is playing out during cherry blossom season in D.C., where these iconic trees are also encountering sea-level rise. After this season’s festival, the National Park Service is set to cut down around 140 of the cherry blossom trees to make room for the construction of taller sea walls.

Among the fallen will include a famously small tree, dubbed “Stumpy” by locals, which has been repeatedly battered by flooding and high tides in the Tidal Basin. (But Stumpy may live on in a way, as members of Friends of the National Arboretum plan to snip some samples from the tree to make genetic clones after construction is done, reports Fox5 News in Washington D.C.). 

Shot from beneath a tree looking up at the pink cherry blossom above.
Image credit: Unsplash

A variety of other plants and crops are flowering sooner than expected as spring weather comes earlier, which can have devastating economic impacts. For example, grapes that bloom earlier in vineyards are vulnerable to cold snaps that can cause dramatic losses for vineyard owners, reports Decanter, a magazine dedicated to wine-related news. 

Migration Mayhem: 

During the first warm and wet nights of March or April, droves of tiny, yellow-spotted salamanders emerge from their hideaway homes in rocks and logs across the eastern U.S. to travel to small ponds of water known as vernal pools that only pop up for part of the year. Here, the elusive amphibians will breed en masse, and leave globs of eggs behind in the ephemeral pools. 

Oftentimes, this short migration requires thousands of salamanders to cross the road, which has become a bit of a spectacle for wildlife enthusiasts in places like Michigan, New York and New Jersey. However, these salamanders—and many other amphibians—have been showing up to breed ahead of schedule, scientists say.

“The general consensus is that climate change is causing phenological shifts,” or changes in the timing of breeding, in a lot of amphibians, Mark Kirk, an amphibian researcher at Allegheny College in Pennsylvania, told me over email in late February.

In 2019, Kirk and his colleagues published a study reviewing 23 years of annual survey data for the spotted salamanders during spring migrations to analyse the potential impacts of climate change on phenology. At the time, there was not a long-term pattern in these shifts, but he said “the past two years have been a very different story” as different parts of the country have experienced abnormal temperatures.

“I am expecting the timing patterns from these past two years to be much earlier arrival dates than our historic surveys” in northwestern Pennsylvania, he added. 

I checked in with Kirk yesterday, and he told me the breeding season is currently “in full swing” and that the first arrival of spotted salamanders was 16 days earlier compared with 2023. Scientists are seeing similar trends with other native amphibians such as wood frogs.

The main issue with this premature showing is if the warm weather does not stick. Warm and wet conditions can come early in the season, but a cold snap later on has the potential to wipe out amphibians’ eggs, Katy Greenwald, a biologist at Eastern Michigan University, told me over email. 

“Many of our local amphibians have adapted to ‘boom or bust’ years of reproduction, and so from a population perspective they are generally OK if they have a bad year in terms of offspring survival,” she says. “It could certainly be a problem if there are a bunch of ‘bad years’ in a row, though.”

Amphibians aren’t the only animal species reacting to these seasonal changes; early springs are also messing with bird migrations and bear hibernations.