Man-made climate crisis led to early flowering of Japanese cherry blossom

(CNN) – Every spring, crowds flock to enjoy the Japanese cherry blossoms – a dazzling pink and white blossom that has been revered in the country for more than a thousand years.

A new study has found that the world-famous sakura plants are blooming much earlier than usual due to human-caused climate change.

Researchers from the UK Met Office and Osaka Metropolitan University in Japan say the climate crisis and urban warming have pushed the “peak flower” bloom period by 11 days.

The trend of early flowering peaks coincides with higher temperatures. Scientists note that average March temperatures in downtown Kyoto have increased by several degrees since pre-industrial times, under the influence of both climate change and urban warming.

Part of the reason is increased urbanization. Cities tend to be warmer than the surrounding countryside because buildings and roads absorb more heat from the sun than the landscape – a phenomenon known as the heat island effect.

The study found that if the greenhouse gas emissions that are warming the planet continue, Kyoto’s cherry blossoms could start to appear before the end of the century — by about another week.

“Our research shows that not only are human-induced climate change and urban warming already affecting the flowering dates of cherry blossoms in Kyoto, but that very early bloom dates, as in 2021, have been estimated at 15 times more, and are expected to happen once At least one every century,” said lead author and climate scientist at the Met Office, Dr. Nikos Christidis.

“Events like this are expected to occur every few years by 2100 when they are not considered extreme.”

Previous cherry blossoms have broader implications for Japan’s economy and environment, and are a symptom of a larger climate crisis that threatens ecosystems everywhere.

“The spring cherry blossom bloom is a culturally important event in Japan,” said co-author Yasuyuki Ono, of Osaka Metropolitan University. The spring festivals that accompany flowering are an important contributor to the local economy, so being able to predict the timing of flowering can be critical.

It is common for locals and tourists alike to take picnics under the cherry trees, and businesses will occasionally offer special meals or produce during the week.

Why are early cherry blossoms important

But it’s not just about tourists scrambling to get to the peak of bloom before the petals fall – it could have a lasting impact on entire ecosystems, and threaten the survival of many species.

The study said the effect of rising temperatures on the natural calendar has gradual effects on the country’s agricultural and land management practices.

It also affects plants, insects, and animals that are highly dependent on each other for their development and life cycles. A change in this cycle can start a chain reaction, causing damage to ecosystems.

For example, plants sense the temperature around them, and if it is warm enough for a constant period, they begin to flower and their leaves begin to appear. Likewise, higher heat can lead to faster growth of insects and other animals.

Different plants and insects may respond to increased heat in different steps, throwing their life cycles out of sync. While she used to time their growth at one time each spring, the flowers may now bloom before the insects are ready, and vice versa—meaning there may not be enough food for the insects or plants.

This same phenomenon is already occurring for many economically valuable crops and plants – posing major problems for food security and farmers’ livelihoods.