The capital of Mexico is a place of contrasts.
Twenty-first century skyscrapers, many with unusual shapes, compete for space with low cinderblock shacks. Ultramodern buildings like the Soumaya Museum share the city with 400-year old classics like the Metropolitan Cathedral.
A north latitude of 19 degrees puts this “City of Palaces” (motto) in the tropics. But with an elevation around 7,400 feet, it’s higher than the tallest mountains in the Eastern U.S., and its climate is moderate. Surrounded by even taller mountains and landlocked, the “Ciudad de Mexico” is one of the world’s most important trade centers. But most significantly, its population of 21 million, if one includes suburbs and satellite towns, rivals Sao Paulo, Brazil, as the largest metropolitan area in the Western Hemisphere.
These many millions of people live in natural settings that pose a large challenge to the quality of life.
When the Aztecs founded the first community there in 1325, they chose a good location. But they couldn’t anticipate today’s millions of automobiles and their exhaust.
With mountains on all sides, the air becomes stagnant in the valley. This gets worse when cool nights produce the frequent temperature inversions.
Cool air settles near the ground and acts like a lid on the atmosphere. Smoke, dioxides, monoxides and other pollutants can’t disperse because they are being held down, and smog is the result.
Recent government efforts to eliminate pollution have led to the disappearance of the city’s iconic Beetle taxis, an army of green-and-white Volkswagens reminiscent of 1950s Germany.
The biggest threat to the 21 million of the Ciudad de Mexico is geology. They live in the shadow of twin volcanoes: Popocatepetl (aka “El Popo”) and Iztaccihuatl. Both are well over 17,000 feet tall. That’s one-half mile bigger than Mount Rainier, Wash. An eruption, which could happen as quickly as the one of Mount St. Helens in 1980, would produce an unimaginable disaster.
The reason for the twins’ existence is the fault line that separates two of Earth’s building blocks, the American Plate and the Pacific Plate. In 1985, a major earthquake (magnitude 8.0) struck along the coast.
Mexico City is 220 miles away, but built on soft sediments. The result was 10,000 deaths and major damage.
Somewhere in the future lies a volcanic eruption combined with another earthquake, and this vibrant metropolis will have to deal with its effects.
Rudi Kiefer, Ph.D., is a professor of physical science and director of sustainability at Brenau University. His column appears Sundays and at gainesvilletimes.com.