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Sky's the Limit: Louisa Emmons '86

by Eileen Callahan '86

	"It never occurred to me that I could apply my training in physics to such a practical issue with day-to-day relevance," says Louisa Emmons '86. "I've always been interested in environmental issues."

Quick: think of a profession that provides opportunities for travel to interesting and exotic locales, a rigorous and disciplined working environment, and the satisfaction of serving the public. The Army? Flight attendant? Whatever your guess, it's a good bet that atmospheric physics was not the first thing to spring to mind. Yet it is just this profession that has taken Louisa Emmons '86 to such places as Antarctica, Easter Island, Hawaii and Greenland.

Louisa's adventures began with her first journey to Antarctica in September of 1987, when she joined a research group studying the stratospheric ozone layer and the hole that appears in that layer over the Antarctic continent during the Austral Summer (September to November). At the time, she was in the middle of her second year of graduate study in physics at the State University of New York at Stony Brook and had not planned on the trip. But at the last minute the research group needed an extra person to go, so she decided to take a semester off and join them. She spent the next two months at McMurdo Station, the main U.S. research facility on the Antarctic continent.

The decision paid off. Louisa was immediately entranced with both the place and the community, and found it exciting to be in such an extreme and unusual environment. The entire continent is covered with ice and snow year round, and the temperatures in early spring, when she was there, range between -40 and +10 degrees Fahrenheit. She was also taken with the close-knit community that developed among the small group of scientists and support staff who, besides living together in very close quarters, shared both an enthusiasm for their various research topics and a love for the strikingly beautiful landscape of craggy, snow-covered mountains.

Perhaps most important, the results of the research on the ozone hole, a phenomenon once known only to a handful of scientists, have since percolated down to our everyday lives and purchase decisions -- surely we've all seen a product with a label asserting that it is "ozone friendly," and maybe even chosen it over another that gave us no such assurances. Thanks to the data gathered and processed by Louisa and many others, scientists were eventually able to pinpoint Chlorofluorocarbons (CFCs) as a major factor in the destruction of stratospheric ozone. (Just one CFC molecule can destroy as many as 100,000 ozone molecules.) Subsequently, scientists have been able to persuade the world's nations to begin phasing out the use of these chemicals, which have been widely employed as aerosol propellants and refrigerants, in an effort to reduce the loss of stratospheric ozone.

A measurement outpost near McMurdo Station, Antarctica

It was just this kind of pragmatic impact -- and the connection to environmental issues -- that attracted the Haverford physics major to Stony Brook and the study of the ozone hole in the first place. "It had never occurred to me that I could apply my training in physics to such a practical issue with day-to-day relevance," she explains. During her years at Haverford, she had spent two summers working with Professor Michael Silvertz at Fermilab, a high-energy physics research facility in the Midwest. While the opportunity to participate in research as an undergraduate motivated her to pursue graduate work, she was not especially drawn to studying the abstract and fundamental concepts central to high-energy physics.

On the other hand, the mystery of the ozone hole seemed like an important topic that she could really care about. "My parents," Louisa says, "are enthusiastic naturalists, and I've always been interested in environmental issues." Haverford's Quaker-inspired emphasis on community service further reinforced her desire to do work that she felt would have a significant impact on environmental conservation. The fact that she might have a fighting chance of explaining her work and its potential applications to non-scientists appealed to her as well.

Although she did visit Greenland in 1991 and 1992 -- and has returned to Antarctica twice for periods of two to four months -- Louisa's travel has not been limited to frigid climes. She has also spent time collecting data in the South Pacific -- on the top of Hawaii's Mauna Kea and on Christmas Island, Tahiti, and Easter Island. Lest the rest of us become too envious of this globe-trotting lifestyle, Louisa is quick to point out that the travel involved was often inconvenient and uncomfortable and that she and her fellow scientists were usually working so frantically gathering data and maintaining sensitive and temperamental equipment that the time available for sightseeing was very limited. They often traveled in army cargo planes, where space for the monitoring equipment took top priority and cabin service was noticeably lacking. On location, they lived in army-type barracks.

Louisa (far right) on a hike with colleagues from her Antarctic research group.

Nonetheless, the scientists on these expeditions, many of whom are outdoor enthusiasts, always managed to find some time for hiking and other sight-seeing excursions. As a reminder of her jet-set days, Louisa has a photo album filled with wonderful pictures of the snow-covered mountains of Antarctica, army-built Quonset huts, and herself dwarfed by a huge stone head on Easter Island.

Since completing her Ph.D. at Stony Brook in 1994, Louisa has continued to work in the field of atmospheric physics, first in Ann Arbor, at the University of Michigan, and now at the National Center for Atmospheric Research (NCAR) in Boulder, Colorado. Ozone is still the subject of Louisa's work, although she is currently studying levels of ozone in the troposphere, the atmosphere level we inhabit which stretches from the ground to between 10 and 15 kilometers above the surface of the earth.

While ozone depletion was the problem Louisa and her colleagues encountered in the stratosphere, the overabundance of ozone is the prevailing concern in the troposphere. While ozone in the stratosphere deflects solar UV radiation away from the earth, ozone in the troposphere reflects infrared radiation and heat back to the earth's surface, contributing to such problems as crop damage, smog, and human respiratory disease. The amount of ozone in the troposphere is related to levels of hydrocarbons and nitrogen oxide, although scientists do not yet completely understand the dynamics of this complex relationship. Hydrocarbons and nitrogen oxide are produced naturally as a result of forest fires and lightning, respectively, but both are also produced in large quantities by the burning of fossil fuels. The puzzle is made more complex by the fact that chemicals in the troposphere can travel widely; high levels of ozone detected in one part of the world may be the result of emissions from quite far away.

Louisa's work at NCAR is contributing to an attempt to synthesize data collected over the years depicting the levels of various chemicals in the troposphere and how they are dispersed around the planet. The resulting information will then be used to evaluate and improve computer models of the troposphere. However, now that recent advances in computing have brought scientists much closer to being able to model the complex processes at work in the troposphere, a new question arises: can we understand it well enough to formulate a recommendation for action that is simple enough to translate into public policy?

"99 percent of scientists agree that current greenhouse gas emissions coupled with rapid industrial growth in Asia and Africa are going to have a significant long-term effect on the atmosphere and the environment. We just don't know exactly what that effect is going to be."

The debate among scientists is not whether our continued addition of pollutants to the troposphere will cause climate change, but when, to what degree, and how much irreparable damage have we already done? "99 percent of scientists agree that current greenhouse gas emissions coupled with rapid industrial growth in Asia and Africa are going to have a significant long-term effect on the atmosphere and the environment," says Louisa. "We just don't know exactly what that effect is going to be." This uncertainty makes it difficult to recommend a single course of remedial action.

Louisa believes that establishing a consensus view to present to the public is one of the major challenges facing atmospheric science today. The success of the campaign to limit the use of CFCs was due, in part, to the fact that the problem in the stratosphere was successfully reduced to a simple relationship between CFCs and ozone; scientists were fairly confident that one adjustment, reducing CFC emissions, could go a long way in combating the problem. By comparison, the troposphere contains so many chemicals interacting in such complex ways that coming to a similarly simple explanation and remedy will be very difficult.

Life has settled down a bit for Louisa since she moved to Colorado and joined NCAR. She's not traveling so much now, and she is spending more time analyzing data than collecting it. She has just married a fellow atmospheric physicist and purchased a home in the Denver area. Having visited the far corners of the globe, she's now looking forward to unpacking boxes that she's been carting around, unopened, for years. And she's starting to feel at home in Colorado, where the brown haze of smog in the Denver sky is clearly visible from her office window -- a daily reminder of the importance of her work.