Cherry blossoms blooming early: A sign of global climate change

Cherry blossoms, a beloved symbol of spring, are blooming earlier than ever. From Tokyo to Washington, D.C., these delicate flowers are demonstrating the effects of a warming planet.

Climate change is taking its toll.

From Tokyo to Paris and Washington, D.C., the shift is the result of unusually warm weather that could pose a threat to these beloved flowers.

Sakura has deep symbolic meaning in Japanese culture, symbolizing the renewal and ephemeral beauty of nature. The age-old tradition of hanami, or “flower viewing,” has become widely accepted around the world, with people flocking to admire the spectacular spectacle of pink cherry blossoms in bloom.

In Japan, predicting the exact moment of peak flowering is serious business. Since 1955, the Bureau of Meteorology has been tracking the blooming of cherry trees at 84 key locations. A tree is considered in full bloom when five or six flowers are open, and in full bloom when 80% of the flowers are open.

However, Daisuke Sasano of the Japan Meteorological Agency said that since 1953, the flowering start date has advanced by an average of 1.2 days every decade. For example, Tokyo’s cherry blossom trees usually bloomed on March 29 between 1961 and 1990, but between 1991 and 2020, they started blooming on March 24. Last year, cherry blossoms in Tokyo began blooming on March 14, the earliest time on record, a phenomenon attributed to “global warming and increasing urbanization.”

The real danger to trees is not a spring that’s too warm, but a winter that’s not cold enough. Winter frost signals to cherry blossom trees that it’s time to wake up and prepare buds for spring. Without this cold trigger, the trees would remain dormant all winter, resulting in no blooms in the spring due to a lack of buds.

In Washington, D.C., where Japan gifted 3,000 cherry blossom trees in 1912, the blossoms reached their second-earliest bloom on record on March 17, nearly a week earlier than expected. In 2017, half of the Yoshino flowers in Washington, D.C., disappeared due to a late frost in mid-March.

This year’s cherry blossoms bloom very early, even before the official start of the National Cherry Blossom Festival in Washington on March 20. From December to February, the Northern Hemisphere experienced its warmest winter on record, reducing the amount of cold weather exposure needed for trees to awaken and bloom during their winter dormancy.

In France’s Molevrier Oriental Park (home to Europe’s largest Japanese garden), some cherry blossoms even bloomed during Christmas due to the mild climate, but subsequent frosts damaged the blossoms. Despite this unusual occurrence, head gardener Didier Touzé has not noticed any significant changes in flowering dates over the years.