How cities are preparing for more extreme weather

2021 has already been another record year in extreme weather events. Floods, hurricanes, wildfires, and other disasters have continued to hit communities around the world with increasing intensity and frequency due to a warming climate. In the US, nearly one in three peoplehas experienced an extreme weather event just between June and August.

Cities are at the forefront of this ongoing crisis. Here’s what needs to happen for them to stay livable in a world of floods, heat, drought, and fire.

Flooding has dominated a year of extreme weather events, with more than1,800 flood events happening across the world so far this year. Some were due to regular seasonal events, like hurricanes or monsoons. But many of the worst this year in cities in Zhengzhou in central China, central Tennessee in the US, and central Germany, were unexpected non-coastal floods that hit urban areas that weren’t prepared for them.

Floods are especially devastating for cities because of how they’re designed—concrete and asphalt pavement don’t absorb water, so it has nowhere to go but downhill into drains, which quickly get overwhelmed in an extreme storm. The result is that 1.47 billion peopleglobally are vulnerable to extreme flooding. Most of these are urban dwellers in coastal cities.

What cities are doing about it:

In a warming world, cities are the hottest place to be. During a heat wave, the concrete and brick surfaces of dense urban jungles trap heat and raise surface temperatures even higher. In recent years, heat waves have gottenlonger, more frequent, and more intense.

That’s a challenge for cities, because heat is deadly: It kills more people in the US each year than any other weather event. Worldwide, it causes more than 637,000 excess deaths per year. Even areas historically accustomed to dealing with heat, like Sicily and Mumbai, are feeling the toll of high heat waves.

What cities are doing about it:

Droughts are harmful for the way they put sustained stress on multiple facets of human societies, including cities. Beyond limiting crop production, droughts hamper electricity grids, and even job prospects. Within the last 20 years, drought has led to global economic losses of at least $124 billion, according to a United Nations estimate.

Humans throughout history have dealt with (and succumbed to) seasonal droughts caused by variations in rain patterns, but climate change is making them worse. The western half of the US has been afflicted with drought for most of the summer; Lake Mead, the largest water reservoir in the US, dropped to the lowest it’s ever been, prompting water-use restrictions for California, Arizona, and Nevada beginning in 2022. In Madagascar, drought is pushing the country into a famine.

What cities are doing about it:

Dry trees and brush caused by heat and drought create the perfect kindling for wildfires. And while seasonal fires are historically a part of the way some ecosystems maintain balance, the enormous, uncontrollable blazes in western North America over the past few years are a direct result of longer, hotter dry seasons spurred by climate change.

In the past, cities have mostly had to deal with wildfire smoke and its effect on air quality (smoke exposure can cause or worsen respiratory disease). But increasingly, the flames themselves are threatening homes and businesses right up into cities.That can disrupt entire economic sectors—losses in the agricultural and tourism sectors from the 2020 Australian bushfires were estimated to beAUD$5 billion(US$3.7 billion).

What cities are doing about it:

Climate scientists largely agree that as a planet, we’ve blown past the point of avoiding the effects of human-generated climate change. The best we can do now is to mitigate its impacts and limit further warming. City policymakers can forge a future that adapts to the reality of climate change, or resist it to preserve our current way of life.

An adaptive future would likely entail some major intentional changes—and, yes, some sacrifices—to life as we know it now. Adaptation could entail managed retreat (moving homes and buildings away from risky coastal areas and resettling them elsewhere) or regular water rationing. In some places, it could mean building homes differently to allow for passive cooling, and changing the hours of the working day so that people won’t be exposed to dangerous heat.

A resistant future will involve change and sacrifice as well, but it will come as a reaction once the worst has already happened. Resistance looks like continuing to build our cities as they are, putting up defenses against weather events, and suffering the consequences when they inevitably fail. That could mean building taller levees that may weather more storms, but massive flooding if (or, likely, when) they break or overtop. It means continuing to build with concrete, resulting in mass casualties from heat-related illness each year. It means continuing to expand cities into fire-prone wildlands, at the risk of massive evacuations and loss of life and property.

Leaders are starting to undertake some adaptive strategies now, but it might be too little too late.