Rethink cities for a changing climate

Rain is the most ordinary of things. It should nourish crops, fill reservoirs and cool the air. Yet, for millions of people living in the world’s big cities, rain has become something to fear.

- Michael Shafer

When the clouds open, traffic stalls, homes flood, and smelly, brown water fills the streets. The sound of rain, once comforting, now signals the opposite.

This is the new face of climate change — not the distant threat of melting ice or rising seas, but the very local, immediate problem of water with nowhere to go.

WHEN CITIES DO NOT BREATHE

Water, by nature, must go somewhere. In the countryside, it soaks into the soil, seeps through roots, collects in ponds, and trickles toward streams and rivers. But in many big, modern cities, the ground is sealed beneath asphalt, concrete and tile. The soil can no longer breathe, and rain can no longer penetrate.

In Bangkok, for example, the city’s storm drains — designed more than half a century ago —can handle only a fraction of today’s rainfall.

When the downpours exceed their limits, which they often do, the water backs up, streets turn into canals, motorbikes and cars stall, and shops flood. For days afterwards, the stink of stagnant water lingers in the air.

This pattern repeats itself elsewhere, too. Jakarta, Mumbai, Lagos, New York — very different cities, same story. As climate change intensifies, rain is falling harder and faster than ever before.

The problem is not only the quantity of water but also the speed at which it arrives, overwhelming drainage systems and our patience.

THE LOST SPONGE

Once, nature managed. Wetlands, forests and floodplains acted as vast sponges, absorbing excess rainfall and releasing it slowly.

But in our rush to urbanise, we drained the wetlands, filled swamps and paved forests to build housing, industrial estates and parking lots.

Without these natural buffers, rainwater has nowhere to go. It rushes across smooth surfaces, collecting pollutants and debris before finding the city’s lowest points — often the poorest neighbourhoods — and settling there.