This map shows the world's 20 most populous urban areas in 2004. With 21,503,000 people, Mexico City ranks third.
Click on image for full size
Data courtesy of the World Gazetteer; illustration courtesy of Mike Shibao, UCAR.
Mexico City, where the field campaign MILAGRO takes place, is a "megacity." A megacity is defined as having 10 million or more inhabitants.
The 21st century is definitely shaping up to be the Urban Century. For the first time in human history, more people live in urban areas than do not. (An "urban" area is a city; the opposite is a "rural" area, which means in the countryside.) In 2000, the world supported 411 cities that each had more than one million inhabitants. While the majority of the world's urban population used to live in Europe and North America, today the biggest growth is happening in developing nations, especially in Asia.
People are moving from the countryside into cities in search of more economic opportunities. That is, they expect to make a better living while working in the city. During the last decade, for example, an estimated 150 million rural Chinese moved to the nation's urban areas, filling megacities like Shanghai and Beijing.
In the future, more and more megacities will form. It is estimated that the number of megacities will reach 26 by 2015. Most cities lack the services to support so many new people coming into them, resulting in unsustainable growth and the pollution that so often accompanies it.
Last modified February 14, 2006 by Nicole Gordon.
Shop Windows to the Universe Science Store!
Our online store
on science education, ranging from evolution
, classroom research
, and the need for science and math literacy
You might also be interested in:
Air pollution comes from many different sources. Natural processes that affect air quality include volcanoes, which produce sulfur, chlorine, and ash particulates. Wildfires produce smoke and carbon monoxide....more
MILAGRO stands for Megacity Initiative: Local and Global Research Observations. What that really means is that a team of researchers from around the world is in Mexico City to study the atmosphere there....more
Mexico City, where the field campaign MILAGRO takes place, is a "megacity." A megacity is defined as having 10 million or more inhabitants. The 21st century is definitely shaping up to be the Urban Century....more
Atmosphere And Clouds Word Search Air Quality Word Search (Printable) -- And the Answer Key Air Quality Word Scramble Greener Machine – Cars: How You And Others Can Make A Difference! Interactive Game...more
Age-Appropriate Windows to the Universe Activities on Climate, Atmosphere and Weather Earth 911 Teachers' Section Educational Materials from the EPA Air Pollution - What's the Solution? A 6-12 Educational...more
About the Campaign MILAGRO Official Homepage Mirage Homepage (Megacity Campaign) Department of Energy Atmospheric Science Program (ASP) MEGACITY Aerosol Experiment in Mexico City (MAX-Mex) NASA’s Intercontinental...more
The MILAGRO scientists will use six different airplanes to study air pollution around Mexico City. Each plane will have different instruments onboard that will help scientists measure air pollution. They'll...more