(CNN) – Every spring, crowds flock to admire the Japanese cherry blossom – a dazzling pink and white color that has been revered in the country for more than a thousand years.
But world-famous sakura plants bloom much earlier than normal due to man-made climate change, a new study has found.
Researchers from the Metropolitan Office in the United Kingdom and the Metropolitan University of Osaka in Japan say that the climate crisis and urban warming have shifted the flowering period by 11 days.
In 2021, the cherry blossoms in the historic central city of Kyoto peaked on March 26, the earliest date of full bloom in 1,200 years. This year, the cherry blossoms burst into bloom on April 1. The researchers, who published their findings in the journal Environmental Research Letters on May 20, said that the extremely early flowering of the cherry blossom is now more common.
The trend of earlier peak flowering coincides with rising temperatures. Average March temperatures in central Kyoto have risen several degrees since pre-industrial times under the influence of both climate change and urban warming, scientists say.
Part of the reason is increased urbanization. Cities are usually warmer than surrounding rural areas, as buildings and roads absorb more heat from the sun than natural landscapes, a phenomenon known as the heat island effect.
But scientists say the bigger reason is the climate crisis, in which the burning of fossil fuels has caused rising temperatures in the region and around the world.
If global warming greenhouse gas emissions continue to be the way they are, by the end of the century, Kyoto cherry blossoms could start arriving even earlier – in almost another week, the study found.
“Our study shows that not only man-made climate change and urban warming have already affected the flowering dates of cherry blossoms in Kyoto, but that extremely early flowering dates, as in 2021, are now estimated at 15 times more likely and expected to happen at least once a century, “said lead author and climatologist at the Met Office, Dr. Nikos Christidis.
“Such events are projected to occur every few years until 2100, when they will no longer be considered extreme.”
The cherry blossoms are in full bloom on the Biva Lake canal in Kyoto, Kyoto Prefecture on April 4.
Michihiro Kawamura / The Yomiuri Shimbun / AP
Earlier cherry blossoms have wider implications for Japan’s economy and ecology and are a symptom of a major climate crisis threatening ecosystems everywhere.
“The blossoming of the spring cherry blossom is a culturally significant event in Japan,” said author Yasuyuki Aono of Osaka Metropolitan University. The spring festivals that accompany flowering make an important contribution to the local economy, so being able to predict the timing of flowering can be crucial.
The peak flowering period lasts only a few days. During this period, hanami – Japanese for “watching flowers” – was a popular activity.
It is common for both locals and tourists to have picnics under the cherry trees, and businesses sometimes offer special sets of dishes or products during the week.
Why early cherry blossoms are important
But it’s not just a matter of tourists trying to catch the peak bloom before all the petals fall – this can have a lasting impact on entire ecosystems and threaten the survival of many species.
The impact of rising temperatures on nature’s calendar has declining effects on agriculture and land management practices in the country, the study said.
It also affects plants, insects and animals, which rely heavily on each other for their development and life cycle. The change in this cycle can initiate a chain reaction, causing damage to ecosystems.
For example, plants feel the temperature around them and if it is warm enough for a constant period, they begin to bloom and their leaves begin to appear. Similarly, higher heat can cause insects and other animals to grow faster.
Different plants and insects can respond to rising heat at different rates, throwing their life cycle out of sync. Where once they recorded growth at the same time every spring, now flowers can bloom before the insects are ready, and vice versa – which means that there may not be enough food for insects or plants.
The change in flowering dates is not limited to Japan or cherry blossoms. This year, spring came early in parts of the United Kingdom, and climate change is causing plants in the British Isles to bloom an average of a month earlier than before, according to a recent study.
The same phenomenon is already happening with many crops and economically valuable plants – creating major problems for food security and livelihood for farmers.
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