Jan 1, 2003 6:00 AMNov 12, 2019 4:51 AM


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52. Great Barrier Reef Dying?

When Ray Berkelmans describes Australia's Great Barrier Reef, he seems to be speaking of an adored but seriously ailing aunt. In 1998, he says, the reef was "a sick patient . . . off-color . . . insipid pale to white." By 2002 the situation was far worse: Nearly 60 percent of the 135,000-square-mile Great Barrier Reef—the world's largest reef ecosystem—suffered some bleaching. "We were speechless," Berkelmans says.

Berkelmans, a research scientist at the Australian Institute of Marine Science in Townsville, blames rising temperatures. Under normal conditions, corals have a symbiotic relationship with algae known as zooxanthellae. The algae produce food by photosynthesis, and the coral protects them. But in the early months of 2002, the local waters were three to five degrees Fahrenheit higher than average. The extra heat impaired photosynthesis and forced the coral to eject the plants that live in its flesh.

The malady may not be terminal. Some bleached colonies contain a few surviving branches, which together with new recruits could build back the reef. In the best-case scenario, recuperation could take seven to 10 years. "The big proviso is, of course, that these reefs are spared another severe bleaching event," Berkelmans says. "If this type of bleaching becomes a regular occurrence—as is predicted—they may never recover." — Josie Glausiusz

51. Were They Right About Super-Weeds?

Environmentalists have long predicted that genetic tinkering with plants could cause super-weeds that might overpower the food supply, but seed companies have dismissed their concerns. Pioneer Hi-Bred International of Des Moines, Iowa, and Dow AgroSciences in Indianapolis, for example, had invested heavily in developing a sunflower seed with a Bt gene that helps plants fight off insects. However, last August a team headed by plant ecologist Allison Snow at Ohio State University demonstrated that this same gene might produce some very tough weeds: She found that wild sunflowers crossed with Bt sunflowers produced offspring that suffered significantly less insect-related damage and produced 50 percent more seeds than control plants without the gene.

Researchers at the University of Lille in France turned up similar results, published in August in a study of gene flow between sugar beets and wild beets. A gene for herbicide tolerance, introduced into crop populations, is "outcrossing," says Henk van Dijk, who participated in the study. "The bolting seed-producing gene in wild beets threatens to become combined with the transgene for herbicide tolerance, which would lead to super-weeds."

Snow wants to do more studies "to figure out if these plants would become a lot weedier." But in October, she announced that Pioneer Hi-Bred International and Dow AgroSciences had denied her access to the Bt gene and to seeds from the first study. Doyle Karr, a spokesman for Pioneer, says the company will not be selling Bt sunflower seeds: "We determined the market would not justify pursuing the trait as a product, and we couldn't justify the responsibility we'd have with this gene." Snow says science is the loser: "This is really exciting research, the only research of its kind in the world." — Eric Neel

43. Forest Plague Threatens Redwoods As long as humans have traveled, pests have hitched rides with them. These days international trade brings thousands of potentially troublesome insects, bugs, and plants to U.S. shores. The latest example: a microbe that has killed off tens of thousands of oaks in northern California and threatens to spread to millions of others.

The outbreak, known as sudden oak death, drew little national attention until this year, when it was found to threaten Douglas firs and California's vaunted redwoods. As pathologist David Rizzo recalled, "No one cared when I said toyon was a host. When I said redwoods might be affected, I spent three days on the phone."

The culprit, a newly discovered fungus called Phytophthora ramorum, may be one of the most virulent pathogens ever to hit American forests. Since it was first identified in Marin County in 1995, the disease has spread across hundreds of miles of California coast and skipped into southern Oregon, defying early efforts at containment. While most pathogens focus on a single species, P. ramorum has wide-ranging tastes: To date, it has been found to infect more than two dozen species, some wholly unrelated, including oaks, bay laurels, rhododendrons, huckleberries, and manzanitas. — Susan Freinkel

99. Biodiversity Worries Increase

The landmark Endangered Species Act turned 29 years old in October, yet the list of endangered species grows every year. At least 596 plant species and 388 animal species are listed as endangered or threatened in the United States alone. Another seven species were added in 2002. One was the Buena Vista Lake ornate shrew, a four-inch-long insect-eating mammal that lives in the wetlands of California's Central Valley. "Most of their habitat has been destroyed," says Chris Nagano, a biologist at the U.S. Fish and Wildlife Service in Sacramento. Buena Vista Lake, southwest of Bakersfield, has been almost completely drained for agriculture, isolating the shrews into four small pockets.

On the plus side, a New England wildflower, the Robbins' cinquefoil, recovered sufficiently to be removed from the list in August. Restricted to the alpine region at the top of Mount Washington and Mount Lafayette in New Hampshire, the plant is a low-lying relative of the rose, with tiny yellow flowers. It had been stomped to near extinction. Fish and Wildlife botanist Susi von Oettingen says, "Hiking trails went through the habitats. Nobody stayed on the trails, so you had a lot of trampling and compacting of soil. You can still see the trail, although people have not walked it for 30 years." The trail was moved, the habitat walled off, and the plants rebounded. But success stories are rare: Once a species is on the endangered list, it is far more likely to die out. — Jeffrey Winters

3. Population Bomb Fizzles The world's population bomb may not go off after all. Demographers assumed that development and education were the principal ways to reduce fertility rates in countries with soaring population growth. However, recent surveys, satellite data, and number crunching presented and analyzed at a United Nations meeting in March show that fertility rates are declining in some less-developed parts of the world. Mexico, Indonesia, and the Philippines have slowed their longstanding high rates of the 1950s to a replacement level of 2.1 children per couple. Thailand has dropped from 6.6 to 1.9; Iran's rate is down to an even 2. India's fertility rate of 6 in the 1950s has now dropped to 3.3.

The widespread availability of contraceptives may be the biggest factor behind the decline. In the past third of a century, their prevalence worldwide has nearly doubled. Even in Brazil, with opposition from the Catholic Church, no government support, and no official family-planning programs, the fertility rate has dropped from 6.2 to 2.3. Roughly 40 percent of Brazilian women of reproductive age have been sterilized, says Joseph Chamie, who is director of the United Nations Population Division. "They've said, 'Enough's enough, we're closing the kitchen. No more coming out of the oven.'" Couples who once had more children than they wanted are now able to take control of the size of their families. Other factors include declining mortality rates and increasing urbanization. "Children aren't necessarily milking the cows, feeding the chickens, slopping the pigs, and taking care of the goats," says Chamie. "So the return from children is relatively limited in urban environments."

If these trends continue, the population of the world may reach 9 billion by 2050 and level off at around 10 billion by the end of the century—1 or 2 billion fewer than earlier predictions. "It won't double again, and no one sees it going to 12," said Chamie. "It's like a slow-moving oil tanker: It's slowing down, but it will take awhile to stop." — Michael Abrams

8. Drinking Water Drugged

Polluted water is nothing new in the United States. We have lived through flaming rivers and caustic creeks that could take the hide off a hound. For decades, however, efforts to safeguard drinking water were hampered because no one had an accurate sense of the full range of contaminants in the water supply, nor of the geographic extent of the pollution. This year two separate research teams unveiled sophisticated new tools to find out exactly what chemical dangers are lurking in freshwater streams.

"Research in Europe in the 1990s showed that pharmaceuticals were turning up in the water," says Dana Kolpin, leader of a U.S. Geological Survey Water Resources Division research team that developed five new analytic methods for measuring water contaminants. "Our big effort was to develop methods to measure very small amounts of organic chemicals." The research team fanned out across 30 states nationwide and conducted two years of sampling from 139 streams. They were chosen, says Kolpin, on the basis of their location downstream from "intense urbanization and livestock production." In a study published in the March 15 Journal of Environmental Science & Technology, Kolpin and his colleagues reported they looked for 95 different contaminants, such as antibiotics, steroids, hormones, antioxidants, plasticizers, and various solvents. They found 82 of them. Nearly 80 percent of the streams showed one or more of the contaminants. The median stream contained seven. Even the good news—that the most frequently detected contaminants like fecal steroids, cholesterol, insect repellent, caffeine, disinfectant, fire retardant, and detergents were found in generally low concentrations—had to be qualified. Many of those compounds have no guidelines for safe amounts, and little is known about the effects of chronic exposure or the interactive effects of compounds that have been detected together.

In a related Environmental Protection Agency study that is still in progress, a team of scientists at the Johns Hopkins Whiting School of Engineering is using gas chromatography and mass spectrometry to detect the presence of various anticonvulsants and anticancer drugs in drinking water. Led by Lynn Roberts and Ed Bouwer, the researchers track samples at sewage-treatment facilities in Massachusetts and Maryland to determine whether and in what quantities pharmaceuticals are getting through the waste-treatment plants and the extent to which they may be accumulating in coastal waters.

The goal of both research teams is to provide a baseline of what organic compounds are in the water, in what quantities, and how they are getting there—key steps toward ensuring that the water we drink isn't killing us. — Michael W. Robbins

80. Yet Another Annoying Cell-Phone Fact There are about 130 million cell-phone subscribers in the United States, and each owns a device likely to become obsolete. So by 2005, says an EPA-funded study released last May, there may be 500 million used, useless phones headed for landfills.

"Because they're so small, cell phones are more likely than computers or televisions to be tossed into the garbage," says Bette Fishbein, a senior fellow at INFORM, a New York environmental organization. Improper disposal is a significant problem because cell phones, like many other electronic devices, are packed with parts made from toxic metals such as arsenic, cadmium, and lead. Although each phone may contain just a few ounces of hazardous material, millions of discarded phones add up to a toxic mess.

The alternative? Fishbein says older phones can be passed along for other people to use, and some manufacturers have established take-back programs that recycle old phones. Perhaps, she says, each phone should be sold with a recycling deposit, like a can of soda. — Jeffrey Winters

60. Another Ice Shelf Disappears A Rhode-Island-size chunk of ice in the Antarctic disappeared in March. Scientists had noted that increasingly warm summers were creating melt ponds on an ice shelf called Larsen B. The weight of the ponds forced cracks in the 650-foot-thick ice. Once the shelf was riven with fissures, it fell apart in a matter of two weeks. "In the last stages, it was like a stack of dominoes," says Ted Scambos, a glaciologist at the University of Colorado's National Snow and Ice Data Center. For centuries Larsen B seems to have followed a pattern of "growing like a fingernail until it calved an iceberg every 50 years or so," Scambos says. That cycle ended in 1995. "That's pretty profound. Things that have survived all the climate wiggles since the last ice age are now disintegrating," he says. Ice shelves keep glaciers from flowing into the ocean. Should many fall apart, sea levels could rise by several yards. "It takes a long time to turn around the effects of greenhouse gases," Scambos says, "so you don't want to wait until we're on the brink of having major changes in sea level before you address these problems." — Michael Abrams

78. Islanders Menaced by Rising Ocean

Pity the people of the Chagos Islands. In the 1960s and 1970s, the British government expelled the entire population of the small Indian Ocean archipelago, then promptly leased the largest of the islands, Diego Garcia, to the United States for a military air base. In 2000 the British High Court ruled that the islanders, most of whom now live in Mauritius, had the right to "return freely and live in their homeland." The bitter irony is that there may be no viable homeland to which they can return. According to a report released by the British Foreign and Commonwealth Office in June, rising sea levels will probably make the low-lying islands uninhabitable.

The average height of Diego Garcia is only about three feet above sea level, and the surrounding water has risen about six inches in the past decade. If the trend continues, the islands could experience increased flooding and erosion, and seawater could intrude into freshwater aquifers. Charles Sheppard, a tropical marine ecologist at the University of Warwick in England, says a warming spike in 1998 killed nearly all the coral in the reefs that ring the islands. "Most of these islands are protected only by a narrow rim of rock around the edge," Sheppard says. "When that erodes through, the water will flood into the center of these islands. Some small islands will simply get washed away."

Nonetheless, some advocates for the islanders are skeptical. "The Chagossians who have seen this study are still laughing," says George Wuethrich, vice president of the Swiss Committee in Favor of the Chagossians. "The United States is still spending billions of dollars on the military base of Diego Garcia. If it believed in an imminent catastrophe, would it invest so heavily there?" The U.S. Department of Defense declined to comment. — Josie Glausiusz

49. Whale Count Plummets Whaling has long been the subject of fierce arguments, but neither side has had much information to back up its answers to the key question of whether some species of whales have been truly endangered. Now, thanks to a rigorous new census compiled by Hal Whitehead, a marine biologist at Dalhousie University in Nova Scotia, it is clear that there are far fewer sperm whales in the world's oceans than previously estimated.

The old estimates were based on 20th-century data from the whaling industry itself, which estimated a worldwide sperm-whale population of about 1.8 million, a number that few scientists found credible. Whitehead compiled the results of many visual censuses from scientific sources worldwide, covering about 25 percent of the sperm-whale habitat. After scaling up that number by calculating whale catches, food sources, and other factors, Whitehead arrived at a count of about 360,000 remaining sperm whales—a fifth of previous estimates.

"The older counts were dubious, to say the least," Whitehead said. "Both the data and the methods were unreliable. Some of the scientists most involved in producing the old estimates have admitted they had little or no validity."

Whitehead's report was submitted last May to the Scientific Committee of the International Whaling Commission. While other factors such as chemical and noise pollution threaten whales, Whitehead believes that retaining the ban on whaling is critical to preserving sperm whales. — Jeffrey Winters

62. Genetically Altered Fish Worries Scientists The idea is enough to make a fish farmer giddy: an Atlantic salmon that grows up to six times faster than it would in the wild and converts food into flesh 20 percent more efficiently than do other domesticated salmon. A fish like that could revolutionize the industry, allowing farmers to harvest two crops in the time it takes one to grow.

That fish is swimming in research tanks, awaiting FDA approval. Aqua Bounty Farms in Massachusetts has developed a transgenic Atlantic salmon. It has the growth hormone of the Chinook salmon and the promoter sequence (a molecular switch that turns on growth-hormone production) of the ocean pout, a fish that grows year-round rather than just during warm-weather months.

The question for the FDA, researchers, and environmentalists is about risk assessment. Aquacultured fish are kept in net pens in the ocean. However, says Robert Dev-lin, a molecular biologist at Fisheries and Oceans Canada, a government agency in Vancouver, British Columbia, "containment is not 100 percent—some of them will escape." What would happen if growth-enhanced Atlantic salmon got loose? Would the transgene propagate itself and potentially replace the wild population? Would the modified fish outcompete its wild brethren? "The potential harm," says Purdue University geneticist William Muir, "is that transgenic fish may alter the niche or adversely affect other species."

Joseph McGonigle of Aqua Bounty says the risk is minimal because "the fish we sell will be female and sterilized so that they cannot reproduce."

Devlin says that's too optimistic: "In our experience, we can't achieve 100 percent sterility." Experiments show that some transgenic fish do outcompete wild fish for food or mates, but no one knows whether that behavior will translate into greater fitness in a natural setting. "It's very difficult for us to take laboratory-based information and turn it into a reliable estimation of risk," Devlin says, but of one thing he is certain: "Uncertainty still prevails." — Eric Neel

27. That Ozone Hole? Never Mind. Remember that hole in the ozone layer over Antarctica, the one thought to be caused by chlorofluorocarbons? It may be on the mend, say Japanese researchers. They say the hole could be on its way to recovery more quickly than anticipated.

Long-range forecasts involving complex modeling had indicated that the hole would only start to close by 2015, but Tatsuya Nagashima, an atmospheric scientist at the National Institute for Environmental Studies in Tsukuba, and his colleagues thought previous studies didn't include enough detail. So they used a pre-existing model of the atmosphere's circulation patterns and plugged in an extra module that took into account the reduction of chlorofluorocarbons. They also posited that levels of other greenhouse gases are low enough not to delay ozone recovery. "The effect of reducing the amount of chlorine-containing compounds in the lower stratosphere seems to be dominant," Nagashima says.

His model suggests that the Antarctic ozone hole should stay about the same for the next decade or so, and then rapid recovery should begin to occur after about 2015. As for the Northern Hemisphere, Nagashima notes that the decline of total ozone calculated there is statistically significant, but that more calculations are needed in order to understand what the change in ozone really is—and what it means. — Jeffrey Winters

79. Condor Chicks Crash

The U.S. Fish and Wildlife Service's California condor recovery program is facing an unexpected problem: litter.

When five California condors laid eggs in the wild last spring, 27 years after the recovery project began, officials were thrilled. When three of the eggs hatched, officials were ecstatic. The first wild-bred birds born in 18 years, all three survived through the summer. For a species roosting on the brink of extinction—as recently as 1983 only 22 condors remained—this was practically a baby boom.

Yet early this fall, just when the first chick was within days of fledging, it was found dead. Soon the remaining two chicks also died. A necropsy on one condor revealed that its insides were loaded with chunks of glass, washers, electrical connectors, even bottle caps. "We don't know the exact cause of death," says Bruce Palmer, condor program coordinator, "but the digestive processes were impaired. Condors are very curious. They eat bone chips and gravel or anything that looks different." Many of the breeding pairs have nested in caves in the remote mountain wilderness areas in and near the Los Padres National Forest in southern California. Officials believe that much of the litter is old and was already in the nest areas when the chicks were born—left there by previous generations of condors or perhaps cached by ravens.

Biologists are considering sifting the floors of the nest caves and cleaning out old litter, and they are not deterred in their determination to re-establish a viable wild California condor population. There are 71 birds living in the wild, including five breeding pairs, plus 129 condors living in captivity. Just watching chicks hatch and survive for a few months is progress. "It's all an experiment," Palmer says. "The condors are learning a lot, and the biologists are learning a lot." — Michael W. Robbins

53. Breath of Reality

As more scientific evidence shows that CO2 is heating up the globe, naysayers have turned to economics to bolster their argument that little should be done. For example, Lawrence B. Lindsey, President Bush's assistant for economic policy, says the Kyoto Protocol, which calls on nations to limit their CO2 production, "could damage our collective prosperity and, in so doing, put our long-term environmental health at risk." Yale economist William Nordhaus developed a model that shows just keeping the amount of CO2 in the air from doubling in 100 years would cost the world about $18 trillion. However, this year Stephen Schneider, a climatologist at Stanford University and editor of the journal Climatic Change, used the Nordhaus model as well as more recent models to demonstrate that containing CO2 wouldn't be nearly as expensive as many economists have suggested.

Schneider says $18 trillion might sound like a lot when compared with the $20 trillion world economic output of 1990, but he insists "you can't use future numbers and compare them to today's economy. That's bait and switch. You can't, on the one hand, grab the models and say it's going to cost us trillions and trillions of dollars but ignore the fact that the very same models say we're going to have a $300 trillion economy in 100 years." Spread the cost of reducing fossil-fuel consumption over the next century, and it turns out that the world would reach the same level of prosperity in 102 years that it is now projected to reach in 100. Schneider says that's a cheap insurance policy to limit "the use of the atmosphere as a free sewer."— Michael Abrams

87. Death In The Oyamel Forest

Monarch butterflies appear to be as delicate as the flowers they favor in our summer gardens, but they are among the hardiest long-distance migrants. Each fall, hundreds of millions of monarchs flee the winter's cold, flying more than 2,000 miles from the eastern United States to the forested high mountains west of Mexico City. But last January, roughly 470 million monarchs—75 percent of the migrant population—perished in a winter storm.

Lincoln Brower, a research biologist at Sweet Briar College in Virginia, and David Kust, a Minneapolis science teacher, saw the devastation firsthand. "[Butterflies] were dead on the ground, piled two feet deep in some places," says Brower. The effects of the storm may have been magnified by years of illegal logging that has thinned the high-altitude habitat. "The forest serves as blanket and umbrella for the butterflies, and the loggers are punching holes in both," Brower says. Monarchs are resilient, he adds, and they seem to have made "a patchy recovery" from this die-off. Nevertheless, he sees the event as a warning: "If the logging doesn't stop, the monarchs won't survive another 15 years." — Jeffrey Winters

12. Estrogens Muddle Bird Sex

Man-made estrogenlike compounds found in pesticides, PCBs, and detergents could cause startling problems for songbirds. A new study suggests that when mother songbirds feed their babies chemically contaminated food, it might disrupt reproduction and lead to profound sexual confusion in the nest.

Scientists at the University of California at Davis conducted a series of laboratory experiments with zebra finches, which exhibit an easily determined sexual difference. "In zebra finches, the males sing, and the females normally don't," says James Millam, a professor of physiology and a specialist in avian reproduction. "There's a part of the finch's brain that controls song, which we call area x. They have brains the size of a small fingernail, but you can see that area under a microscope." Normally, male zebra-finch brains have an area x, and female brains don't. But when Millam and his associates dosed pairs of zebra finches orally with estradiol benzoate, a form of the hormone estrogen, and octylphenol, an industrial surfactant that sometimes mimics estrogen, they documented several effects. For example, female finches started singing. "When the females were treated with estradiol, their brains developed an area x. We could see it," says Millam. Moreover, the males showed reduced fertility, and there were increases in eggshell breakage.

Previous research has shown that estrogenlike compounds can cause birth defects and reproductive anomalies in alligators as well as some aquatic birds that feed on fish and reptiles exposed to the common water pollutants. "The Environmental Protection Agency is now working up a screening program for endocrine-disruption research on mallard ducks and one species of quail," says Millam. "We think they should be looking at songbirds as well. No one has yet studied the effects of estrogen on wild songbird populations." — Michael W. Robbins

58. More CO2 Trouble

In the classic 1962 sci-fi film The Day of the Triffids, a race of vicious vegetables spreads terror across the planet after a meteor shower blinds those who have seen it. Now a real celestial threat is propagating a different kind of killer plant: Woody vines known as lianas are growing so quickly in the Amazonian rain forest that they're choking trees. The culprit seems to be increased carbon dioxide in the atmosphere.

Ecologist Oliver Phillips at the University of Leeds in England has analyzed liana growth in half a million square miles of rain forest in Peru, Bolivia, and Ecuador. While tree density increased by 0.3 percent per year in two decades, liana density rose tenfold. The lianas monopolize resources like carbon dioxide—which is rising by 0.5 percent per year globally—eventually covering some trees and pulling them down. That could slow the rain forests' overall absorption of carbon dioxide, fueling further global warming. "Nature has been protecting us from the worst impact of what we're doing," Phillips says. "But there are limits to that, and those limits are possibly being reached in the Amazon." — Josie Glausiusz

20. EPA Confirms Global Warming Really Exists

Within the next 100 years, the earth will heat up by three to nine degrees Fahrenheit. Droughts will strike at the American heartland. Winters will be warmer, summers stickier. Deserts will be changed into grasslands. The snow on the mountains will melt earlier in spring. The seas will rise and swallow the shores. But there will be more corn, barley, sorghum, and soybeans. There will also be more trees, more forest fires, and, yes, more floods, storms, and pestilence.

Are these the predictions of a fiery environmental radical? Well, no. They come from a report by the Environmental Protection Agency, issued to the United Nations in May. In an about-face, the agency agreed that global warming is happening; that humans, by pumping greenhouse gases into the atmosphere, are responsible; and that the American environment is likely to change dramatically over the next century. (President George W. Bush dismissed the report as the work of "the bureaucracy.") The agency then offered a singular solution: Rather than ratify the Kyoto Protocol on climate change or reduce carbon dioxide emissions, Americans should simply adapt.

They may have to start right away. The first six months of 2002 were the warmest on record in the Northern Hemisphere and the second warmest globally. In the United States, the summer was the hottest since the dust-bowl era. Meanwhile, melting glaciers, forest fires, and floods are commonplace.

Ecologist Gian-Reto Walther of the University of Hanover in Germany thinks rising temperatures may have already had dramatic effects. Last March Walther published a report on worldwide changes in migration, breeding, and flowering. A one-degree rise in the global temperature over the past century, he says, could account for the shifts.


Mosquito-borne diseases such as dengue fever have moved northward in Asia and Latin America over the past decade.

Numerous bird species in both Europe and North America now migrate four days earlier in spring and breed nearly five days earlier.

Red foxes have moved north in Canada as Arctic foxes retreat.

Plants in Europe and North America now unfold their leaves and flower up to three days earlier than in previous decades.

The tree lines in Europe and New Zealand have climbed to higher altitudes.

Arctic shrubs in Alaska have invaded previously shrub-free areas. In Antarctica mosses now colonize formerly bare ground.

39 butterfly species in North America and Europe have shifted their range northward by 124 miles over the past 27 years.

In Britain newts are invading ponds earlier in spring, where their populations prey upon earlier-breeding frogs.

Six periods of mass coral bleaching, attributed to warmer ocean temperatures, have occurred since 1979. The temperature of tropical oceans has risen by 1.8 to 2.6 degrees Fahrenheit over the past 100 years. — Josie Glausiusz

29. Himalayan Glaciers Melt

If Sir Edmund Hillary and Tenzing Norgay were to set out to conquer Mount Everest today, they would have to hike an extra two hours to reach the edge of the glacier that once sat close to their base camp. In the 50 years since their ascent, the glacier has retreated three miles. But that two-hour trek would be trivial compared with the problems facing the people of the Himalayas. A report issued by the United Nations Environment Program in April says at least 44 lakes in Nepal and Bhutan are filling so rapidly with icy water from melting glaciers that they could burst their banks within five to 10 years. Hundreds of thousands of people could drown as roads, bridges, and hydroelectric plants wash away.

Geologist Jeffrey Kargel of the U.S. Geological Survey in Flagstaff, Arizona, says the overwhelming majority of glaciers around the globe are retreating. Kargel is the international coordinator of Global Land Ice Measurements From Space, a satellite program dedicated to photographing each glacier on Earth every year. He has no doubt about the cause. "It's definitely due to global climatic changes," he says. Central and southern Asia are most threatened by severe changes. Glaciers act as a liquid bank account for people in those areas, storing snow in winter and releasing melted water slowly in the summer. If glaciers disappear, summer crops will wither and die. Kargel warns of a "day of reckoning" yet to come.

In other areas, however, there could be an upside to the receding ice. In the Canadian Yukon Territory, for example, glacial retreat has revealed a wealth of ancient archaeological relics, as well as freeze-dried voles, shrews, birds, and a 7,500-year-old bison. Melting ice may also expose mineral ores. In the Himalayas, ice-covered peaks form an impenetrable barrier between China and southern Asia. "If many of these mountain passes become ice-free, then one can imagine railroads and highways being built," Kargel says. "I'm not saying I want this to happen. I'm a great fan of wilderness, and roads are the absolute curse of wilderness. However, this is not my land. If transportation corridors are developed, it will promote trade between China and southern Asia. There will be major shifts in economic and military alliances." — Josie Glausiusz

28. A Warning From Frogs

This is not a good time to be a frog. In New Zealand, four species of frogs that are living relics, similar to the earliest frogs from 200 million years ago, are dying from viral and fungal infections. The culprits—chytrid fungus and ranavirus—are not limited to New Zealand; they're also spreading through Australia and the Americas.

Biologists fear chytrid is carried from pond to pond on the boots of outdoorsmen, and from country to country in the tanks of pet salamanders or frogs. "You can't really talk about numbers of frogs that have died," says population ecologist James Collins of Arizona State University. "You have to talk about populations and species that have disappeared."

The chytrid fungus is only one agent of decline. Frogs are also prey to ranavirus, a lethal waterborne microbe found in the western United States and southwestern Canada. It acts so swiftly that researchers think the best way to preserve species may be to catch uninfected frogs and return them (or their descendants) years after the virus has worked through the population.

What is wrong? Immunologist Nick Cohen at the University of Rochester in New York says the causes are complex and not understood but notes that environmental degradation has weakened the frogs' immune systems. Along with chytrid fungus and viruses, frogs are threatened in other ways. The trematode, a parasite that tunnels under the skin of tadpoles, has been implicated in frog deformities throughout North America. Also, in April researchers reported that frogs raised in water laced with trace amounts of atrazine, the world's most widely used farming herbicide, develop sexual deformities. Atrazine is found in virtually every U.S. lake and stream and even in rainwater. The effects of these threats may be synergistic; Penn State biologist Joseph Kiesecker reported in July that chemical pollution can make frogs more susceptible to trematode attacks.

Tyrone Hayes, a biologist at the University of California at Berkeley who is investigating atrazine, says it may not be bad only for frogs. Reptiles and mammals have similar developmental mechanisms and may also be at risk. — Jeffrey Winters

48. Will the Navy's New Sonar Harm Whales?

After years of debate, the National Marine Fisheries Service gave its approval this summer to the U.S. Navy's use of a new low-frequency active-sonar system for locating enemy submarines. That prompted the Natural Resources Defense Council and a coalition of other environmental groups to sue the Navy in federal court, claiming the sonar poses an unacceptable risk to marine life.

The Navy sends out powerful pulses of low-frequency underwater sound that can travel hundreds of miles from a ship-towed source, then listens for and interprets the echoes. Environmental critics contend the sonar pulses are too loud, producing a devastating impact on whales, dolphins, and other marine mammals that rely on echolocation to communicate, navigate, and locate prey.

In March 2000, 16 beaked and minke whales beached themselves in the Bahamas after a mid-frequency active-sonar exercise by a Navy ship. Six died. Four carcasses were tested, of which three had ear damage and one had bleeding around the brain. The Navy agrees that extended use of mid-frequency active sonar at close range did cause harm to those whales. But the Navy, the Fisheries Service, and some marine scientists contend that low-frequency active sonar, when operated according to Navy guidelines, is not hazardous except at very close proximity. "We've never seen an animal damaged by [low-frequency active] sonar," says Roger Gentry, head of the Fisheries Service's acoustics program. According to guidelines based on several years—and $10 million—of environmental-impact research, the Navy is not permitted to use the low-frequency sonar within 12 nautical miles of any coastline, in any marine sanctuary, near any marine-mammal "biologically important area," or in polar seas. It must monitor an area of 1.25 miles around a low-frequency active-sonar array and shut down if marine mammals or sea turtles are detected.

Researchers who conducted one environmental-impact study in the Pacific Ocean before the Fisheries Service approved deployment of the system concluded that low-frequency sonar is not likely to have a dramatic effect on the hearing and activities of marine mammals. The team observed gray whales interacting less than six miles from a low-frequency array. "We saw normal behavior, normal singing, surfacing, feeding," says Kurt Fristrup, a biologist. "Nothing we saw would indicate a threat to survival and breeding." — Michael W. Robbins

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