Today's date:
Spring 2001

Plan Now to Avoid Megacities Nightmare

Mario Molina, professor of chemistry at MIT, was awarded the Nobel Prize in 1999 for his work on atmospheric chemistry and stratospheric ozone depletion. He also is director of a joint MIT-Harvard Project on Megacities, using Mexico City as the case study. He spoke with NPQ recently.

NPQ | By the middle of this century, there will be 50 "megacities" in Asia alone, each with a population of 20 million or more. If the pollution is bad now, what will it be like when the whole planet has gone urban? Won't these cities, in effect, be gigantic bonfires heating up the climate?

MARIO MOLINA | Large population concentrations plus economic growth will mean not only widespread pollution, but also an increasing lack of mobility because of congestion. Unless action is taken now to plan the growth of these areas before they reach megastatus, the health of millions will be at stake, particularly in the developing regions of Asia and Latin America, where there is little pollution control of any kind.

But the problem extends beyond the direct health and mobility costs to the actual inhabitants of these megacities. As you suggest, with so many megacities dotting the planet, their collective output of carbon dioxide and other gases will further contribute to climate change. Their chemical emissions will further deplete our protective ozone layer.

Moreover, we now know that pollution drifts across the Earth, worsening the "background" air quality in places far from the source of the pollutants. This will only increase as a result of larger and larger cities in the Northern Hemisphere, meaning, for example, that in the future California may not be able to meet its strict clean-air standards because of "background" pollution that has drifted across the Pacific from Asia. Background air quality is already detectably worse in Europe.

Clearly, the cost for society will be much less if we act now to design cleaner and more efficient urban systems rather than trying to cope with the health and clean-up costs, not to speak of the economic losses, after the fact.

Solving the serious problem of air pollution requires an approach that integrates science, technology and politics. It is not just a matter of understanding physical and chemical processes, but also an ability to balance economic, social and technological factors, to make decisions in the face of uncertain and incomplete data, and to educate and involve the public to ensure their acceptance of pollution control policies.

For example, in the United States high taxes to cut down consumption of gasoline are politically unviable, whereas they are more acceptable in Europe. In India, the government had to back down in its effort to close small industries that were polluting because of the uproar over job loss. Dealing with the social issues involved is every bit as important to solving the problem as understanding the science.

NPQ | Los Angeles has made great strides in reducing air pollution. Even Mexico City, where fetuses have famously been found to have toxic levels of lead in their blood from the air their mothers breathe, has begun to improve. What is the key to these changes?

MOLINA | In both cases, the key element was government regulation, primarily requiring the use of unleaded gasoline and catalytic converters in all new cars. Most cities in developing countries, including China, do not include these items on their planning agenda.

While some components of pollution in Mexico City have improved, we still face the problem of particulate matter that enters the lungs and smog that comes from gas fumes, nitrogen oxide and light mixing at our high altitude.

California has begun to take the further, more difficult step of regulating such decentralized lifestyle activities as backyard barbecues and requiring more use of water-based instead of oil-based paints. Although the transportation sector is still the main culprit, when cities grow to millions of inhabitants, every act involving a chemical or creating particulate pollution adds up.

Clearly, the next step must be a shift to cleaner cars that are energy efficient, such as hybrid fuel or electric cars. A small number of people are already buying these automobiles, but to have a significant impact on climate change and pollution, their use must be widespread-which means they must be required by governments.
Even so, with cleaner cars than we have today, the temptation to have more and more cars can make the situation worse in an absolute sense. What is essential is to have a well-integrated plan that makes a city work efficiently and cleanly, including through well-designed public transportation systems.

Without question, more innovative thinking is required to link the use of clean cars (and the powerful attraction of individual mobility) with public transportation. One such idea, for example, involves the sharing of inexpensive electric cars to go the relatively short distances to and from public transportation sites.

NPQ | The Chinese government still has a central-planning apparatus intact. Perhaps it ought to require not only catalytic converters and unleaded fuel but, within a reasonable time frame, hybrid fuel cars?

MOLINA | While some parts of the Chinese government have been receptive to pleas for planning ahead, the dominant view is worrisome: China just wants to build cheap cars so more people can have them. Mexico used to have this policy until the last president, Ernesto Zedillo. Car manufacturers in Mexico built two sets of cars-one for export and one for the domestic market. The ones for Mexico were a little cheaper but much dirtier. In the future, all cars being made in Mexico will abide by cleaner standards.

China and other developing countries ought to follow a more enlightened policy of adopting standards in sync with the US with some years' lag. After all, they have a great advantage: They don't have to invest in creating clean-fuel car technology but only need to purchase or manufacture the cars. It is really essential that they look ahead at these options before they build out their megacities and are trapped in a pollution nightmare.

back to index