Greening Tokyo’s Concrete Jungle

Environment Trends & Culture - August 7th, 2009

by Darrell Nelson

Demand and planning for green buildings is rising like a skyscraper on steroids, the product of everything from high energy prices to corporate vanity to a better understanding of the dividends paid by environmentally sensitive facilities.

A recent United Nations report found that buildings are responsible for as much as 40 percent of the world’s greenhouse gas emissions. Architects, designers, and innovators have developed a slew of methods to build commercial and residential facilities that generate as much energy as they use and improve employee health and productivity, all while serving as major corporate image boosters. Japan itself jumped on the bandwagon in 2005 when the Tokyo Metropolitan Government (TMG) issued the Tokyo Green Building Program, designed to require building owners and new construction projects to take into account the environment in four areas: rational use of energy, optimum use of resources, preservation of the natural environment, and mitigation of the heat island phenomenon.

But the adoption of these guidelines and rules has been very slow. I recently caught up with the Principal Architect of Van Der Architects Japan KK, Martin van der Linden, to discuss how Tokyo has attempted to green its buildings, if it all. “The future is obviously moving toward highly concentrated cities rather than sprawls, so we need to localize things. A focus is needed on things like vertical planning to combat the rise in city temperatures; I really believe that all large buildings above a certain height need to be required by law to green their roofs.” This technique could certainly be used to combat the rising Urban Heat Island (UHI) effect, which contributes to the oppressive humidity each summer in Tokyo. The problem doesn’t just effect how many shirts we go through each day; UHI effect is also to blame for the increase in Tokyo’s unpredictable localized torrential rains. But does just adding a few plants on a roof really work?

According to surveys by the TMG, when the temperature of concrete surfaces rose to 55ºC in mid-summer, the surface in green areas was as low as about 30ºC. So where can we find these oases in the concrete jungle? One of the best examples of a ‘green building’ can be seen not in Tokyo but down in Fukuoka. Across Fukuoka, designed by Emilio Ambasz & Assoc. was created to “preserve as much green space as possible, while still fitting in a large office building.” The green roof reduces the energy consumption of the building by keeping the temperature inside more constant and comfortable. Green roofs also capture rainwater runoff and support the life of insects and birds. A manmade structure has brought about a diverse ecosystem in what would normally be another grey brush stroke on the monotonous skyline.

Despite the science and what feels like an increase in humidity and heat each Tokyo summer, adoption of the practices above has been painfully slow. Recently national and local governments have tried tactics such as promoting greening through subsidies, reductions in fixed property taxes, bonus plot ratios, and so on. However as Martin van der Linden commented, “the problem, as with any targets to mitigate the environmental challenges we face in the world today, is that the Japanese Government must pass stricter laws, and more importantly enforce these laws before we will see any substantial change.”