Will climate change make it impossible to see cherry blossoms in Japan?

Cherry blossom season is one of the most beloved times of year in Japan, drawing tourists from around the world to witness the breathtaking beauty of the Sakura trees in full bloom.

However, in recent years, the timing and duration of cherry blossom season have been shifting due to the effects of climate change. Rising temperatures and other environmental factors have begun to impact the delicate process of cherry blossom blooming, leading to concerns about the future of this cherished cultural event.

The record for the fastest bloom continues to be broken

With rising temperatures in Japan, the blooming period of cherry blossoms has been shifting earlier each year. In 2023, the Japan Meteorological Agency announced that the first bloom was observed in Tokyo on March 14, marking the earliest cherry blossoms have bloomed alongside 2020 and 2021 since statistics began in 1953. This trend towards earlier blooming has been particularly noticeable since the 1990s, around the same time the maximum temperature in March began to rise in Tokyo.

As a result, the earlier blooming of cherry blossoms has become more pronounced each year, raising concerns about the long-term impact of climate change on this iconic symbol of Japanese culture.

How climate change affects the blooming process?

During late fall and early winter, cherry buds go dormant to survive the cold weather. This dormancy is broken by a certain period of cold weather called the “chilling hour,” which varies with the type of cherry tree. Winters that are too mild can cause the cherry buds not to develop properly, delaying or interrupting the flowering process.

After that, temperatures rise during the spring, the blooming process begins, and flowering occurs when the daily maximum temperature total reaches a certain value. However, if temperatures rise higher during the flowering period, it can accelerate the flowering time and shorten the flowering period, which may impact pollination and reproduction.

For instance, the Someiyoshino cherry tree requires exposure to low temperatures of around 5°C for a certain period to bloom properly. Global warming is likely to prevent this temperature drop in some regions, such as Kagoshima Prefecture and coastal areas of Kyushu and the Kanto region, causing the Someiyoshino to not bloom in the future.

Professor Hisanori Ito conducted a simulation of cherry blossom blooms up to the year 2100, under the scenario where temperatures in various regions of Japan average 2 to 3 degrees Celsius higher. The simulation showed that cherry blossoms, which previously bloomed gradually from southern regions, are expected to bloom simultaneously throughout the country.

Sadly, this trend has already started to be observed in Fukushima Prefecture, in the middle part of Japan, which has shown a gradual acceleration in bloom times, while Kagoshima Prefecture, which is in the South region, has not seen almost anything change. Additionally, some areas may not bloom at all or will not fully bloom all at once due to fluctuating blooming periods.

1.5 degrees looms, but we can still change our future

In Japan, cherry blossoms have long been a symbol of new beginnings, often seen in celebratory scenes like entrance and initiation ceremonies which typically take place in April, coinciding with the start of the new semester. However, the early blooming trend of cherry blossoms in recent years could change these joyful moments.

The IPCC’s latest report, the “Synthesis Report for Policymakers,” highlights that the global average temperature has already risen 1.1°C from pre-industrial levels and could reach 1.5°C by the 2030s if greenhouse gas emissions aren’t reduced. Nevertheless, the report also points out that halving emissions by 2030 in line with the 1.5°C target is achievable across all sectors. It requires effective effort from everyone. As individuals, what must we do to protect the cycle of nature’s bounty?