Two years after the remnants of Hurricane Ian dumped up to 10 inches of rain on New York City in simply two hours, the metropolis is once again inundated today by extreme rainfall. It is among the many cities worldwide grappling with a counterintuitive impact of local weather change: Sometimes, it will get wetter, not drier. 

On a warming planet, it’ll rain extra and particular person storms will get extra intense. This ache might be particularly acute in city areas, that are constructed on stormwater infrastructure designed to deal with the rainfall of yesteryear. Think again to what the builders of the final century wished: sewers and canals that funneled rainwater as rapidly as potential right into a river, lake, or ocean, earlier than it had an opportunity to build up. That labored advantageous, more often than not. But over the intervening years, uncommon catastrophic flooding has been rising extra frequent. Ancient wastewater techniques are actually tasked with eliminating ever-bigger inundations. 

Today’s concrete- and asphalt-heavy cities are additionally now a type of seal atop the panorama. They have plenty of laborious surfaces like roads and parking heaps, and possibly solely a smattering of softer surfaces like parks. Because they’re impermeable, water can’t sink into the bottom—it has to rage throughout city, turning subway stairs into waterfalls and swamping schools.

Better sewer techniques might be indispensable, positive, however planners are additionally essentially reimagining city areas as “sponge cities” designed to mitigate flooding by absorbing water. Clearly, NYC nonetheless has a methods to go by way of flood administration. But the town now has greater than 12,000 inexperienced infrastructure property throughout the town, mentioned Edward Timbers, spokesperson for the NYC Department of Environmental Protection, in an announcement offered to WIRED. This contains rain gardens, or strips of roadside greenery that take up rainfall, and blue belts, or conserved pure drainage techniques like ponds and wetlands. All that inexperienced infrastructure helps hold rainwater out of the sewage system.

“NYC has the largest and most aggressive green infrastructure program in the nation,” Timbers says. “Last year we developed new stormwater regulations that require any new development or redevelopment to manage stormwater onsite, and not allow it to drain off into the roadway where it can contribute to flooding.” 

Likewise, Los Angeles is deploying rain gardens, in addition to directing rainwater into spreading grounds—principally, massive dust bowls the place water trickles underground. In the drought-wracked American West, this may ship as a lot rainwater as potential back into aquifers, to be tapped for ingesting water as wanted.

Green areas don’t simply mitigate flooding. They beautify the city panorama and improve residents’ mental health. They filter out microplastics and other pollutants, protecting them from reaching delicate water our bodies like rivers. And when the climate is sizzling, they cool neighborhoods, as a result of vegetation “sweat.” This reduces the urban heat island effect—the tendency for cities to get far hotter than surrounding rural areas. If these inexperienced areas had been urban farms, they may do all that whereas additionally producing meals. 

The bother is that city land is dear, so inexperienced areas aren’t low-cost. Where it’s not potential to plant the panorama, cities like NYC are deploying permeable pavement. Instead of performing as a barrier for stormwater, these surfaces let rain soak into the underlying dust. Some cities are additionally beginning to cost water clients extra stormwater fees, utilizing satellite tv for pc photos to find out how permeable a property is and charging if there’s numerous pavement as an alternative of vegetation.

The metropolis of the long run could also be spongier in methods which might be clearly verdant or extra delicate. But if that makes them extra gratifying and extra resilient because the planet warms, the rains of the long run could also be a bounty, not a burden.