More and more of us live in urban areas. Today, some 55 percent of the world lives in cities, and a quarter of all humans live in the 2,500 most populous cities. That percentage is expected to increase dramatically in the coming decades. By 2050, as the global population swells and urbanizes, about 70 percent of people will live in metropolises.
Earth’s climate, meantime, will continue to change in response to ever-rising greenhouse gas concentrations in the atmosphere. Further warming will induce dramatic changes in nearly every corner of the planet. Some of those effects are already playing out.
Many of the impacts of future warming will be felt by the growing population of city dwellers. Cities concentrate people, infrastructure, activity, and many other resources into tight spaces, which means they’re particularly vulnerable to the effects of climate change. Hotter temperatures put extra stress on human bodies, asphalt-covered roads, and more; more intense droughts can tax water systems; more intense rainfall can flood cities’ drains.