LONDON: As humans become an urban species researchers find evidence that cities with more green space are best for human wellbeing.
For the first time in human history, more than half the world now lives in cities. Later this century, the proportion could rise to two-thirds.
Even without global warming because of a build-up of carbon dioxide in the atmosphere, itself the consequence of fossil fuel combustion, the cities are feeling the heat.
That is because dark materials and hard surfaces – tarmacadam, brick, cement, tiles, slates, gutters, railway tracks, flyovers, motorways and so on – absorb the heat but not the rainwater that, as it evaporates, could damp down that heat.
As a consequence, cities become “heat islands”: places conspicuously hotter than the surrounding countryside. According to a report in Nature, the annual average temperature in Los Angeles in California has risen by more than 2°C since 1878, and by mid-century the sprawling megalopolis is predicted to face 22 days a year of extreme heat: that is, with temperatures of more than 35°C.
Now British and US scientists are trying to work out the shape of the ideal city. Pack people together with lots of green spaces around, say the British. And keep the people cool with trees, parks, roof gardens to help them withstand the heat, add the Americans.
Researchers at the University of Exeter in the UK and the University of Hokkaido in Japan report in the journal Frontiers in Ecology and Environment that they analysed nine case studies of cities worldwide to work out the arrangements with most benefits to humans.
Dense but spaciousThe answer – separate from the climate question – is that dense settlements but with big parksand nature reserves deliver the greatest sense of well-being and the healthiest urban ecosystems.
