From the impeccable Zen gardens of Kyoto to the sacred forests surrounding shrines such as Meiji Jingu in Tokyo, Japan is admired for its traditional gardens that often provide a welcome respite from the concrete jungles that surround them.
However, rapid urbanization over the past half century ¡ª 91% of people nationwide currently live in urban areas compared to around 75% in 1975 ¡ª has gone hand in hand with a reduction of urban green spaces.
¡°If farmland and woodland is taken into account, the total area of green spaces in Tokyo has decreased by around 219,000 hectares ¡ª approximately 22% ¡ª from 1965 to 2005,¡± says Yoshinori Akiyama, senior deputy director of the environment office at the land ministry.
Even though Tokyo¡¯s urban parks have increased by 16,000 hectares over the same period, the city still has a remarkably low percentage of park space ¡ª 6.2% ¡ª compared to dedicated spaces found in capitals such as Stockholm (29.4%), Paris (24.3%) and London (11.2%).
The loss of such green spaces has tangible consequences on the wellbeing of citizens and the environment. Analysts say that it is important to re-imagine how cities are designed and built so that planners can respond to the challenges posed by increasing urbanization and climate change.
If properly designed, urban green spaces ¡ª even small ones ¡ª can lower surrounding air temperatures, boost biodiversity, and provide a whole range of health and social benefits.
The urban heat island
The loss of green spaces in Japan¡¯s cities has been occurring against a backdrop of rising global temperatures, a warming effect that is even more pronounced in urban areas.
In the 20th century, the average temperature in six large cities in Japan, including Tokyo and Nagoya, increased by 2-3 degrees Celsius, compared to a global average of 0.6 degrees.
¡°This temperature pattern ¡ª whereby temperatures remain higher in central areas compared to suburban metropolitan areas ¡ª is known as the ¡®urban heat island,¡¯¡± says Takehiko Mikami, emeritus professor at Tokyo Metropolitan University, who has conducted extensive research on urban climatology and the impact of green spaces on city temperatures.
The urban heat island effect is caused by two main factors: heat emissions connected to human activities (such as engine emissions and air conditioning) and the heat retention of artificial surfaces, such as cement or asphalt, compared to natural ones typically found in forests or fields.
Cement and asphalt have a low albedo, which means that solar energy is absorbed during the...
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