A cloak of smog gives Fresno, California, a hazy look. Smog, a hybrid of the words "smoke" and "fog," is caused when sunlight reacts with airborne pollution, including ash, dust, and ground-level ozone.
Photograph by Sarah Leen
The promise of jobs and prosperity, among other factors, pulls people to cities. Half of the global population already lives in cities, and by 2050 two-thirds of the world's people are expected to live in urban areas. But in cities two of the most pressing problems facing the world today also come together: poverty and environmental degradation.
Poor air and water quality, insufficient water availability, waste-disposal problems, and high energy consumption are exacerbated by the increasing population density and demands of urban environments. Strong city planning will be essential in managing these and other difficulties as the world's urban areas swell.
Threats
- Intensive urban growth can lead to greater poverty, with local governments unable to provide services for all people.
- Concentrated energy use leads to greater air pollution with significant impact on human health.
- Automobile exhaust produces elevated lead levels in urban air.
- Large volumes of uncollected waste create multiple health hazards.
- Urban development can magnify the risk of environmental hazards such as flash flooding.
- Pollution and physical barriers to root growth promote loss of urban tree cover.
- Animal populations are inhibited by toxic substances, vehicles, and the loss of habitat and food sources.
Solutions
- Combat poverty by promoting economic development and job creation.
- Involve local community in local government.
- Reduce air pollution by upgrading energy use and alternative transport systems.
- Create private-public partnerships to provide services such as waste disposal and housing.
- Plant trees and incorporate the care of city green spaces as a key element in urban planning.
Related Features
Shop National Geographic
Advertisement
Green Living Hot Topics
-
Organic Air Fresheners
Avoid toxic chemicals and create a calming space.
-
Surprising Recyclable Household Items
With a little know-how, you can recycle more than you think.
-
Side Effects of Vegetarianism
Find out how to stay healthy and eat lower on the food chain.
National Geographic Magazine
-
Pollinators
They are the Earth’s pollinators. And they come in more than 200,000 shapes and sizes.
-
Age of Man
It’s a new name for a new geologic epoch—one defined by our own massive impact on the planet.
The World's Water
-
Visualizing Our Global Water Footprint
You might be surprised to see how the daily choices you make affect critical watersheds around the world.
-
Why Care About Water?
National Geographic's freshwater initiative is a global effort to inspire communities to conserve water and restore rivers.
Special Ad Section
