Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS

Program Notes


An Atmosphere of Change

In 1975, when Mario Molina first uncovered the detrimental effects of chlorofluorocarbons, or CFCs, the Mexican-born chemist couldn't even believe the significance of his findings. In fact, he thought perhaps he'd made a mistake. But it wasn't long before he and scientists worldwide recognized the profound implications of the discovery: that these man-made chemicals pose a serious threat to our planet's well-being. And in 1995, Molina and his colleague Sherwood Rowland received the highest honor bestowed upon a scientist: the Nobel Prize.

Molina's work fostered important policy changes regarding CFCs among nations across the globe. A diverse group of scientists of color elsewhere in the United States are also working to protect and preserve the environment, albeit on a local scale. Molina's story and the tales of two such scientists, are told in An Atmosphere of Change.

photo Molina was working with Rowland at the University of California at Irvine when the pair found that CFCs, the seemingly benign chemicals used in spray cans and cooling systems, could wreak havok by destroying ozone. Ozone protects the Earth from the sun's harmful ultraviolet rays and is found in a layer in the upper atmosphere.

The problem then was how to convince people of the danger. "No one had heard of this invisible gas, way up in the sky, shielding us from invisible rays. It sounded very esoteric," explains Molina. Public concern for the problem mounted in 1984, when a large hole in the ozone layer was discovered over Antarctica.

Back in his laboratory, now at the Massachusetts Institute of Technology, Molina calculated that ice clouds - like those found over the Earth's poles - could accelerate the destructive power of CFCs, thus explaining the hole's location and size. His work provided much of the basis for the groundbreaking Montreal Protocol, an historic agreement among 53 nations to limit the production of CFCs.

Environmental dangers are found underfoot as well as in the sky. On his job for the National Biological Service, Keith Miles creeps through the mud on the shores of San Francisco Bay, searching for mussels. Because these shellfish soak up toxic chemicals discharged into the Bay by local oil refineries and waste water treatment plants, they serve as sentinels, alerting biologists like Miles to potential problems. His findings, which are reported to government officials, will influence policies designed to keep the environment clean and healthy.

His work also takes him to the remote Aleutian Islands in the Bering Sea, where he and a colleague perch near a cliff's edge to gently weigh a grey, down-covered bald eagle chick in its nest. Even though these remote islands are far from factories, pollution from an old munitions dump may be damaging the bird's habitat in unseen ways.

photo An African American who grew up amidst concrete buildings in southeast D.C., Miles didn't have much exposure to the natural world or to real scientists, except those he saw on TV shows, like Jacques Cousteau or Marlin Perkins on Wild Kingdom. "Now, I realize the incredible value of those shows," says Miles, "because they inspired my interest in marine biology and wildlife science."

Like Miles, Karen Medville, a Cherokee Indian, didn't have any scientific role models as she was growing up. At the age of 16, working in a bar to support herself, she became pregnant. Rather than go on welfare, she went to college, working her way toward a Ph.D. in environmental toxicology.

Medville's doctoral research explores the health effects of very low levels of lead on humans. Seventeen percent of US children have lead poisoning, which can lead to serious problems such as mental retardation and learning difficulties. Medville wants to know whether very small amounts of lead - lower levels than now permitted by United States law - have damaging effects on human cells.

In addition to her research, Medville makes time to mentor Native American students in a summer environmental program on the St. Lawrence River in New York. For 400 years, the local Mohawk Indians depended on the river for fish. But local factories that discharge toxic pollutants and a new hydroelectric dam have all but eliminated that tradition. With help from her 16 year-old daughter, Medville tells students about the environmental fate of products like shampoo and detergent, and teaches them how to test the river water for signs of pollution.

She feels strongly about encouraging Native-American students, because she believes that their cultural influences can have a positive impact upon science. By way of example, she echoes a traditional Native-American saying: "When you make decisions in your own life, and for other people, you should make sure that those decisions are looking ahead for seven generations."



Resource Center
About the Series || Directories
Resources || Educational Materials

Activity Center || Utilities || Main Menu


Copyright © 1996 Blackside, Inc. All rights reserved.