Salt Lake writer Terry Tempest Williams is among a half-dozen naturalists scheduled to address a most chilling question during the Utah Museum of Natural History's upcoming Winter Lecture Series: Is this the end of nature? The series starts Monday, Jan. 7, at East High School, and continues for the succeeding four Mondays there, with the addition of Williams' talk on Saturday, Feb. 2, in the University of Utah's Fine Arts Auditorium.

In 1890, the U.S. Census Bureau completed its decennial tally of all Americans and announced a surprising fact: the frontier had ended. The population was spread out from coast to coast, leaving few unpeopled regions between.Today, a bit more than a century later, the museum, based at the University of Utah, is asking not whether the frontier has ended but if nature itself is ending.

Speakers in the series, interviewed by the Deseret News, feel that may be overstating the situation but say the natural world certainly is changing drastically for the worse.

"It is presumptuous for us to assume that nature will end per se. The earth will survive us," said Williams, a former Deseret News columnist and author of books including "Coyote's Canyon," "Pieces of White Shell" and "The Secret Language of Snow."

"I think the point is, nature as we know it is changing and the changes are largely destructive. The problems we face are enormous: deforestation, ozone depletion, overpopulation."

It's easy to become paralyzed in despair, she said. But one person can make a great difference. Williams quoted the anthropologist Margaret Mead as saying that a small group of thoughtful, committed citizens can change the world - and that, indeed, it's the only thing that ever has.

"Each of us must ask ourselves what we can do in our own lives that can enhance our relationship to the natural world," Williams added.

"One gesture can inspire a movement. We must extend our notion of community to include all life forms, plants and animals. We must take nothing for granted."

Another speaker in the series, Bob Reiss, a journalist who has written for the Washington Post and Smithsonian Magazine, will discuss one of the greatest threats to nature today, the destruction of the Amazon rain forest. His talk is scheduled Jan. 28 at East High School. His findings about the damage are to be published this year in his book, "The Last Mile," to be issued by Simon and Schuster.

Tropical rain forests cover about 7 percent of the planet, he told the Deseret News. They are found in a band that extends along both sides of the equator where the plants get 130 inches of rainfall, or more, per year.

"An area the size of Austria is being cut or burned or bulldozed or drowned under dams every year," he said in a telephone interview from his home in Brooklyn. "Tropical forests are dying out."

However, Reiss said, a lot more rain-forested land remains "than many conservationists would have you believe."

This was brought out by his recent journey to Rondonia, Brazil, a state in the western Amazon. In 1980, many conservationists had predicted that by 1990 the state would be completely deforested, he said.

"But it's still 75 percent forested. That's not to say that it's not disappearing at a rapid rate," as many rain forest regions in the Amazon are. Scientists disagree on the rate, but all confirm that the forest is going.

"There are obvious consequences," he said. "Estimates of extinction rates vary from one species a day going extinct to 10,000 species a year."

So far, scientists know only 1 percent of the plants in the tropical forests, he said. Sometimes a species may exist on only an acre.

Plants that are known are the sources of between 25 percent and 50 percent of the world's medicines, Reiss said. They help in everything from making painkillers to fighting cancer to heart disease.

As the rain forest disappears, he said, "most scientists feel we'll lose medicines that haven't been discovered yet . . . . It's not illogical to assume that the other 99 percent will give us many more medicines."

Even more ominous, burning the rain forest releases carbon that trees have extracted from the atmosphere and stored for 200 years - and it removes those plants from the carbon monoxide/oxygen cycle. The results could be sweeping climatic changes.

Burning the forests in the Amazon, Indonesia and other tropical countries may contribute to global warming, the greenhouse effect.

Possibly between 1 billion and 2 billion tons of carbon per year explodes into the atmosphere because of burning the forests. The air doesn't have much carbon to begin with, he said, and "it doesn't take much to change the balance."

Reiss said a majority of scientists think deforestation has a role in the earth's warming, but that it is not as big a role as industrialization. Exhaust fumes from American cars, and chlorofluorocarbons used in refrigeration, have a greater impact.

He held out hope for improvement, however. Changes could come from reduced auto emissions and improvements in controlling chlorofluorocarbons and, in the tropical countries, land reform so poor people won't want to destroy more of the forest to create farms. Also, he said, in tropical countries population control is vital.

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Museum's lecture series spotlights leading authors, scientists

"The End of Nature?"- the Winter Lecture Series sponsored by the Utah Museum of Natural History - spotlights some leading authors and scientists who have one thing in common, a deep concern for the natural world.

The series' schedule is:

- Monday, Jan. 7: "The Earth." Bill McKibben, author of the controversial book "The End of Nature," will discuss the dangers of global environmental change; 7:30 p.m. at East High School.

- Monday, Jan. 14: "The Flora." Sarah Laird, director of the Periwinkle Project, Rainforest Alliance, will talk about the relationship of medicine and plants endemic to the rain forests; 7:30 p.m., East High School.

- Monday, Jan. 21: "The Fauna." "Conserving Tropical Wildlife: Present Problems and Future Solutions" is the topic of John W. Terborgh, director of the Duke University Center for Tropical Conservation; 7:30 p.m., East High School.

- Monday, Jan. 28: "The People." Bob Reiss, author of the soon-to-be-published book about the Amazon rain forest, "The Last Mile," will discuss cultural and economic factors that affect the forest's survival in Brazil; 7:30 p.m., East High School.

- Saturday, Feb. 2: "The Individual." Salt Lake author Terry Tempest Williams, naturalist-in-residence at the museum, will talk about the importance of the individual in conservation; 2 p.m., U. Fine Arts Auditorium.

- Monday, Feb. 4: "Coming Home." Elliot A. Norse, chief scientist at the Center for Marine Conservation in Washington, D.C., will address the destruction of America's own ancient forests in the Pacific Northwest; 7:30 p.m., East High School.

Tickets are $3 per lecture, with a series pass available for $13 to members of the Utah Museum of Natural History or the Red Butte Garden and Arboretum, and $15 to non-members.

The talks are sponsored by the museum, based at the University of Utah; the Red Butte Gardens and Arboretum; Salt Lake Community Education; Tracy Aviary; Hogle Zoo, the university's biology department; stations KUER, KUED and KULC; Kennecott; the Lawrence T. and Annie T. Dee Foundation; the Ruth Eleanor and John E. Bamberger Foundation; O.C. Tanner; The Nature Conservancy; the University Park Hotel, and Northwest Pipeline.

Tickets are available at the museum, located on the U.'s circle drive, and Red Butte Gardens. For details, call 581-4887 or 581-6927.