For centuries, British flowers have been blooming like clockwork. A few months into spring, sometime around May or June, the nation bursts into color.
Since the early 1980s, however, hundreds of plants have grown out of sync with the seasons, which means they’re also unraveling from the complicated tapestry of interactions that keep ecosystems sustainably functioning.
When analyzing the first blooms of 406 plant species from 1753 to 2019, researchers found a clear and worrisome shift.
On average, flowers in the UK are blooming almost a whole month earlier than they were before 1986. In 2019, the first mean flowering date was as early as April 2.
Obviously, not all plants bloom at the same time. Herbs and trees are the first to flower, sometime in mid-April. While shrubs take about a month longer to open up.
The whole timeline, however, has been pushed forward as the climate changes.
Today, human-caused global warming is progressing at a rapid and unprecedented rate, and it’s impacting the very function of Earth’s ecosystems.
Something as dependable as the changing of the seasons is no longer so.
Early spring warming in the UK appears to be changing the amount of rain that falls and the snow that melts, and both of these factors are important when it comes to a budding flower.
If temperatures continue to rise, the authors worry there will be a further shift in first flowering dates, possibly starting March or even earlier.
This transition could lead to some plants, including crops, to bud far too early, causing them to freeze or suffer frost damage.
Short-lived plants like herbs are shifting the fastest due to their short generation time, allowing them to more rapidly adapt to the new temperatures, but this may not be helping them.
“We do not know whether adaptive evolution will allow populations to reach new [optimum flowering timing] rapidly enough to keep pace with climate change,” the team warns, echoing other researchers.
Researchers fear these changes will lead to agricultural losses and extend the allergy season. But it’s not just humans that will be impacted.
“The timing of plant flowering can affect their pollination, especially when insect pollinators are themselves seasonal, and determine the timing of seed ripening and dispersal,” the authors write.
“Plant flowering also influences animals for which pollen, nectar, fruits and seeds are important resources… “
The effects of an early flowering season could therefore ripple through ecosystems, causing what scientists call ecological (or phenological) mismatch – when the lifecycles of species that have evolved together and depend on each other fall out of sync.
This can lead to disrupted migration patterns, species starvation, outbreaks of pests and disease, and even extinction.
England isn’t the only nation that has to worry about its flowering season. Earlier spring temperatures are being recorded throughout the world, both in the northern hemisphere and the southern hemisphere.
Last year, in Japan, cherry blossoms bloomed the earliest they have in 1,200 years.
Japan is unusual in that it has kept careful records of flowering events like these for hundreds of years. In the UK, on the other hand, observations of first flowers are most reliable after 1952.
Even with just a few centuries of data, however, the result of our emissions is clear to see. Climate change is winding up our Spring clock, and we don’t know if we can wind it back again.
The study was published in the Proceedings of the Royal Society B: Biological Sciences.