Design Urban Design 10 Things That Make a Great Green City By Jennifer Hattam is a freelance journalist based in Istanbul, Turkey. She covers environmental, social, urban issues, food, and travel. our editorial process Jennifer Hattam Updated December 24, 2012 Share Twitter Pinterest Email Design Tiny Homes Architecture Interior Design Green Design Urban Design With 180,000 people moving to the world's cities every day, 75 percent of the global population is expected to be living urban lives by 2050. That concentration makes cities massive contributors to overall levels of pollution and CO2 emissions, but also provides the opportunity to enact changes that can have a broad and deep impact. As Ricky Burdett, the director of the Urban Age program at the London School of Economics and Political Science said at the group's recent conference in Istanbul, "If you make cities more efficient, you make the world more sustainable." Here are 10 ways to do just that. 1 of 10 Plentiful Parks Peter Zelei Images / Getty Images Parks are the "lungs of the city," architect Frederic Law Olmsted famously said about New York's Central Park. From the 500-year-old Giardino della Guastella in Milan to downtown Houston's new Discovery Green, parks provide both a place for harried city residents to take a deep breath, relax, and connect with nature, and a cooling counter to the heat-island effect created by all that asphalt. (Not to mention a buffer against flooding.) Green space has even been shown to improve urbanites' physical and mental health. 2 of 10 Efficient Public Transportation Travelpix Ltd / Getty Images New York City subway. While commuters in Beijing, Dubai, and Lausanne, Switzerland, have shiny new metro systems to ride to work, transit authorities in Mexico City, Istanbul, and Los Angeles have cleared the way for buses by simply putting them in their own lanes. But whether they're high-tech or humble, transit solutions that allow people to get around quickly and easily without a car are a key element to a green city. 3 of 10 Quality Public Space John Wilkinson Photography / Getty Images Strøget pedestrian zone in Copenhagen. Amid all the skyscrapers and busy roadways, a good green city has places that are built (or renovated) to human scale, places where people can safely walk and happily gather. Whether it's New York's High Line, a old railway bed converted into an aerial walkway, or a popular pedestrian-only street in Curitiba, Brazil, such places not only encourage getting around on foot, but reduce the need for large private dwellings by creating communal space for people to enjoy. 4 of 10 Bike Lanes Richard Newstead / Getty Images Critical Mass in Vancouver. While the density of cities makes them great in theory for getting around by bike, heavy traffic (and angry drivers) can make cycling unpleasant and even dangerous without designated lanes. The most bike-friendly cities create separated bike paths, provide parking (and even solar-powered showers!), institute bike-sharing programs, and allow cyclists to bring their bikes on buses for longer trips. 5 of 10 High-Profile Green Buildings vuk8691 / Getty Images Green roof on an EPA building in Denver. Showcase developments that seek to be the biggest, tallest, fill-in-the-blank-iest green building may get flak for their aesthetics or be seen simply as "window dressing" for governments and corporations seeking some green cred. But as long as they're not all a city's doing, a prominent, striking eco-friendly structure such as the San Francisco Federal Building or the green roof on Chicago's city hall provides a very visible symbol of green intentions and draws attention to the latest technologies. 6 of 10 Comprehensive Recycling and Composting Programs Cavan Images / Getty Images New recycling bins being distributed in San Francisco. Yes, recycling is the classic individual environmental act, but it's not much good without someone to provide conveniently placed bins and reliable collection. The greenest city initiatives are going further than gathering cans and bottles, by adding electronics and food waste to the list of items recycled and composted, and by instituting larger-scale programs to recycle water for industrial use. 7 of 10 Mixed-Use and Infill Development Westend61 / Getty Images Mixed-use development in Washington, D.C. Good planning is key to a green city. While other metropolises sprawl further and further out, Hamburg, Germany, is renovating its obsolete harbor into a walkable mixed-use neighborhood with office, retail, and residential space, while Sacramento, California, is giving new life to old alleyways. Such projects "recycle" existing space that's already woven into the urban fabric, making them easy to get to and get around. 8 of 10 Green Leadership Genevieve Engelhardt / EyeEm / Getty Images Climate action in St. Paul, Minnesota. Not every city official is going to be a "knight on a shining bicycle" like London Mayor Boris Johnson, who stopped an assault as he was cycling by. But government officials such as Atlanta Mayor Shirley Franklin, former Austin Mayor Will Wynn, and the city council of Marburg, Germany, are heroes in their own right for cleaning up their cities' sewer systems, promoting wind power and biodiesel, and making solar installations mandatory on new and renovated buildings. An active citizenry provides leadership from the ground up to prod or encourage politicians in the right direction. 9 of 10 Smart Energy Policies P. Steeger / Getty Images A solar array in Barcelona. Buying renewable energy and mandating efficiency measures are two ways a city can use its economic clout to help build a market for greener products while lowering its own environmental impact (and, often, operating costs). Phoenix, Arizona, for example, is boosting the amount of power it draws from renewable sources and constructing new city buildings to LEED standards, while San Francisco is building a big new solar array, Austin, Texas, is mandating home energy audits, and New York City is looking into offshore wind farms. 10 of 10 Good Green Fun Nick Rains / Getty Images Farmers' market in Santa Monica, California. Going green shouldn't be all work and no play, and the best green cities celebrate their eco-friendly lifestyles with farmers' markets full of tasty (and unusual) treats, bars and restaurants serving the best organic fare, intriguing exhibits by ecologically minded artists, and music festivals that offer bike valet parking and solar-powered stages.