This summer may have been a washout in many parts of the world, but we all know these days that when a heatwave hits a big city, you really feel it. The majority of us now live in huge, heat-absorbing islands of steel and concrete – and that means temperatures here can be several degrees higher than they would be otherwise.
Cities also generate three-quarters of the world’s greenhouse emissions. Add in the fact that they guzzle two-thirds of the global energy supply, and it seems they have a responsibility to lead by example when it comes to cooling down the planet.
Tokyo is showing the way. In the run-up to the Olympics and Paralympics, the Japanese capital introduced a series of measures to help with heatwaves. All have the potential to help other cities reduce the ‘heat island’ effect.
To start with, solar-blocking paint was applied to a load of pavements and new buildings. According to the Tokyo Metropolitan Government, that alone helped reduce surface heat by 8C. The Japan National Stadium was also built using more wood and natural resources than usual. That means less heat absorption than steel, and fewer carbon emissions during construction.
Many indoor venues have also done away with conventional air conditioning. Whereas most old cooling systems properly devour energy, Tokyo deployed a new type of ‘green air tech’ that pushes cool air in a spiral formation to lower parts of buildings, where people are actually likely to be. It reduced the amount of energy needed to cool a room by as much as 40 percent compared with normal AC.
Tokyo isn’t alone in treating the city as a laboratory. Chicago has incentivised developers to cover roofs with plants. More than 500 new gardens, spread over 5.5 million square feet, have helped lower roof temperatures by 3C to 4C. Singapore is piping chilled water through buildings to help cool the air in its financial district. And London has led the way when it comes to vast low emission zones to curb movement of pollution vehicles: fewer cars mean lower temperatures.
There’s so much work still to be done – but it seems the days of the sweaty, panting commuter could be numbered.
More cool plans: