More than half the world’s population lives in urban areas. By 2050 cities will likely be bursting with two-thirds of the people on the planet. Since urban areas already account for an estimated 76 percent of CO2 emissions from energy use—and many are especially vulnerable to flooding and higher temperatures—it makes sense that city officials are taking on climate change. After all, doing so also gives them a shot at reducing pollution, improving aging infrastructure, and making their cities more attractive to residents and businesses.


Chicago has built what city officials call the “greenest street in America”—a two-mile stretch in the industrial neighborhood of Pilsen. Bike and parking lanes are paved with smog-eating concrete; sidewalks are made from recycled materials. Wind and sun power streetlights. Bioswales, thick with drought-tolerant plants, divert storm water from overburdened sewers. The spruced-up streetscape uses 42 percent less energy than it used to—and cost 21 percent less than a traditional road project.

Illustration of smart streets

Roads paved with photocatalytic concrete can neutralize harmful pollutants before they contaminate the environment.


Scroll to continue


Buildings are responsible for approximately one-third of all greenhouse gas emissions, a figure likely to shrink as more cities require municipal buildings to be energy efficient. Increasingly, government office buildings will have solar panels and even gardens on roofs, sensors to douse lights in empty rooms, windows lined with heat-trapping film, and energy-efficient HVAC systems.

Illustration of green buildings


Despite its reputation as a water guzzler, Los Angeles is pioneering ways to capture every drop that falls from the sky. On a flood-prone block of Elmer Avenue in the east San Fernando Valley, storm water used to be funneled into drains and out to the ocean. A $2.7 million project has transformed the block into a sponge, capable of collecting enough water yearly to supply 30 families.

Illustration of sustainable water management
    Capturing water for reuse
  1. Rain barrels collect rainwater from the roof and save it for irrigation.
  2. Rain gardens replace lawns—and soak up excess water if the rain barrels overflow.
  3. Driveways and sidewalks made out of permeable materials allow water to seep through them.
  4. By the time storm water filters down to the aquifer below, it has been cleansed of pollutants.

“Mayors don’t have to wait for national governments or a new global climate agreement to act. They can take action today—and increasingly, they are.”

Michael Bloomberg

former mayor of New York City, May 27, 2014

Comment on this article

Share this article