What makes a city green?
Over half of humans now live in cities. Environmental scientists have often criticized cities for expanding into farmland and for their tremendous consumption of energy, water, food, concrete, and land. But the environmental cost per person is usually lower for urban living than for suburban or rural living, especially in wealthy countries. Because they are compact, cities require fewer miles of roads, water and sewer lines, less heating, and fewer private cars per household. Because distances are shorter, roads and utility infrastructure are shared, apartments or row houses share heat, and public transportation reduces the need for driving to work. Polluted cities can be unhealthy, but well organized cities can provide cultural resources and preserve environmental resources in many beneficial ways.
Recreational space has physical and emotional benefits for urban residents. Living vegetation and soils cool the local microclimate, store nutrients and moisture, and provide habitat for birds and other wildlife.
Recycling collection is easiest where transportation is minimal and where recyclable materials are abundant. Recycle bins present in bins in Kuala Lumpur, Malaysia accept all kinds of recyclables.
Local farm economies are more viable if farmers can sell direct to consumers—something that is much easier where there are lots of buyers in one place. Cities have become an essential income source for many produce farmers.