Today, over half of the world’s population lives in cities. Cities devour 75 percent of the planet’s natural resources and pump out 75 percent of all waste. Can this change? The following urban communities have, whatever their means, started to address urban environmental problems.

Charlottetown
The capital of Prince Edward Island may be small, but it has large aspirations for reusable forms of energy. Innovative schemes include district energy and bioenergy, a process that creates electricity by burning biomass fuels (wood, crops, manure, etc.). The system is “carbon-dioxide neutral” since the CO2 produced in the burning would have been released into the atmosphere by the biomass anyway. Trigen-PEI is a private company that burns 66,000 tonnes of waste from sawmills and landfills. This not only reduces the area required for garbage dumps by 90 percent, but the bioenergy produced goes on to heat the University of PEI, the provincial government buildings and several other structures. Though there is some resultant pollution, Trigen-PEI has equipped its stacks with state-of-the-art filters, “air scrubbers” and multi-cyclones, all of which remove particles before belching the exhaust into the sweet maritime air.

Copenhagen
Government-owned bike racks are a familiar sight in downtown Copenhagen; they are loaded with city bikes that anyone can use after inserting a twenty-kroner coin (roughly four dollars) into the bike’s lock. The cyclist is then free to roam to his or her heart’s content within a designated perimeter. After use, the bike can be returned to any rack and the deposit coin retrieved. In order to prevent theft and scavenging, the city-bike parts require special tools and include components that are simply incompatible with any other bike model. With over 300 kilometres of bike paths in the city—a system that’s been gradually built over the past century—Copenhagen is clearly serious about this form of transportation. By 2012, the city hopes the number of people commuting by bike will increase from an already impressive 34 percent to 40 percent.

Mexico City
In the mid-nineties, a group of twenty NGOs by the collective name of Anadeges launched an initiative that would allow poor people in Mexico City to produce their own organic food, using their balconies, rooftops and backyards. Anadeges proposed drainless containers that could be layered with leaves, grass clippings and soil. This system proved successful in growing leafy foods—herbs, lettuce, spinach—and some fruit-bearing plants like the essential Mexican hot pepper. The meagre financing behind this accomplishment inspired a few urban-farming innovations: using urine as a free fertilizer and inside-out tires as growing containers. The latter helps to solve another of Mexico City’s environmental problems: mountains of discarded rubber.

Toronto
The past five years have been environmentally interesting in Toronto. In North York, you’ll find St. Gabriel’s Village—a luxury-housing complex that incorporates green roofs, numerous windmills, solar panels and a hybrid generator. Downtown is now home to a deep-lake water-cooling system. The largest of its kind in the world, this system uses the frigid water in the depths of Lake Ontario in order to keep buildings in Toronto’s core cool in the summer, allowing participating structures to go without expensive and polluting air-conditioning systems. And the municipal government has made some serious greening efforts: the city’s new Green Bin program allows residents to put organics—fruit and vegetables scraps, paper towels, coffee grinds, etc.— out on the curb for collection and composting.

Dushanbe
Thanks to a toxic mix of reckless industrialization, political instability and geographic isolation, the capital of Tajikistan is an environmental disaster. Since gaining independence from the former Soviet Union in 1991, the country has experienced a civil war, a refugee crisis, tainted water catastrophes and a number of other calamities. In the last four years, the country fell thirty-five places in the World Economic Forum’s Environmental Sustainability Index. A gross lack of funds, the closing of necessary agencies and the emigration of the vast majority of Tajikistan’s specialists have not helped. Despite the gloom, however, Dushanbe is turning its attention to environmental concerns. At present, international groups—the city has been overtaken by acronyms—are administering local efforts, with a particular emphasis on low-cost, lo-fi tactics: summer camps, awareness projects and student-driven “green patrols.”