National Geographic : 2015 Nov
Protected bike lanes encourage people to commute by bicycle rather than by car. “Adaptive” LED street lights use less energy by responding to traffic and weather conditions. Shade trees and other vegetation can reduce city temperatures and energy use. Roads paved with photocatalytic concrete can neutralize harmful pollutants before they contaminate the environment. Car travel decreases in cities where devel opment centers around transit stations. SMART STREETS Chicago has built what city officials call the “greenest street in America”—a twomile stretch in the industrial neighborhood of Pilsen. Bike and parking lanes are paved with smogeating concrete; sidewalks are made from recycled materials. Wind and sun power streetlights. Bioswales, thick with droughttolerant plants, divert storm water from overburdened sewers. The sprucedup streetscape uses 42 percent less energy than it used to— and cost 21 percent less than a traditional road project. 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. “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 Cities London has installed more than 700 electriccar chargers throughout the city. In Amsterdam more than a quarter of all trips in the city are made by bicycle. Georgetown, Texas, one of the fastestgrowing U.S. cities, plans to be powered by renewable energy by 2017.