The cement, glass and steel that give shape to urban life have also turned modern cities into dangerous heat sinks. Scorching sunlight gets absorbed, stored and slowly emitted in a bubble of warmth that can push city temperatures as much as 3°C (5.4°F) above the surrounding countryside. This dynamic, combined with the increasingly extreme heat waves produced by climate change, helped drive record-breaking highs in Delhi (49°C) and London (40.2°C) over the past few months. Thousands of citydwellers died in sweltering cities this summer.
But even on the hottest days during what will likely be one of the five hottest years in modern history, there are urban neighborhoods that succeed at blunting climate-driven heat waves. Evidence of these effective solutions capable of saving countless lives can be seen from space.
Satellite images produced by the European Space Agency, working in part with data from NASA and the US Geological Survey, now have a high enough resolution to allow for temperature variations to be parsed on a street-by-street level. These snapshots of heat differences offer clear evidence of cooling strategies that can counteract what researchers term the “urban heat island effect,” in which city temperatures get that extra boost.
“The strongest weapon that we have for lowering temperatures are trees, and the best thing we can do for cities are green corridors that connect existing green areas,” says Eleni Myrivili, the city of Athens’ Chief Heat Officer. She will become the United Nations’ Global Heat Officer later this year. “We have to lead with trees to begin with, and then use technology and materials to figure out other ways of cooling spaces,” she says.
Some of the best ways to lower temperatures in an overheated metropolis come from nature and the wisdom of ancient civilizations that invented city living. Others adapt the latest technological innovations. Here’s a look at the neighborhoods that managed to curb this summer’s most extreme heat.