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Our World — 15 September 2007

MUSIC: "Our World" theme

Straight ahead on "Our World" ... A status report on endangered species ... a new way to learn about dark matter ... and climate change and its impact on agriculture ...

CLINE: "Countries that are closer to the Equator have higher temperatures already. And as they heat up they get into ranges that are beyond the tolerance levels for the crops."

Those stories, cancer patients and the lingering after-effects of chemotherapy, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

The World Conservation Union this week released its annual Red List of Endangered Species.

The Swiss-based group warns that more than 16,000 species of plants and animals are threatened with extinction. Another 25,000 are classified as endangered.

Michael Hoffman of the group's biodiversity unit spoke to reporters at the National Zoo here in Washington. He says the new Red List paints a grim picture.

HOFFMAN: "When it comes to the status of biodiversity worldwide, the news generally is not good. Unfortunately, when it comes to this year's Red List, there's not a great deal that gives us hope that the one-in-three amphibians that are threatened with extinction, or the one-in eight birds that are threatened with extinction are doing any better.

If there is a marquee family of animals that symbolizes threatened species, it could be the Great Apes, whose numbers continue to decline. Russell Mittermeier, who heads the World Conservation Union's primate group, says the Western Lowland Gorilla in particular is more endangered than ever.

HOFFMAN: "This species has been upgraded from endangered to critically endangered in large part because of the great amount of bush-meat hunting that is taking place throughout most of its range, logging which continues and is increasing in some areas, and superimposed on all this you have this issue of Ebola outbreaks, which seem to hit gorillas particularly badly."

Population of the Western Gorilla has declined by more than 60 percent over the past quarter-century. Tens of thousands of the animals still survive, but as Mittermeier put it, the trends are downward.

Corals have made their first appearance on the Red List this year, their coastal-water colonies threatened mainly by El Niño and by climate change.

In China, the Yangtze River Dolphin is listed as possibly extinct, although there was an unconfirmed sighting last month. That dolphin is threatened by pollution, river traffic and fishing.

Many plant species are also in danger: the Red List includes more than 8,000 species of plants. A Malaysian herb called the Woolly-stalked Begonia was declared extinct this year.

Caroline Pollock, who runs the World Conservation Union's Red List program in Switzerland, says protecting endangered plants and animals is for our benefit, not just for the threatened species.

POLLOCK: "Animals and plants, all across the whole planet-they give us our food. They give us our livelihoods. They give us our furniture, the roofs over our heads. They give us medicines-a whole range of things we take for granted nowadays, they all come from species. And the more species we lose, the more we are risking our own health, our own welfare and we are risking our future generations. It is something we really absolutely need to pay attention to and do something about."

You can see a full list of threatened species at, or get the link from our site, And stay tuned for another story about how scientists are using genetic analysis to help preserve one species of whale, coming up later in the show.

Scientists have known for some time that most of the stuff in the Universe is so-called dark matter — material that can't be seen directly because it doesn't interact with light. That makes it very difficult to study. But now, as we hear from VOA's Jessica Berman, researchers say the arrangement of the oldest stars in the universe may provide clues to help them learn more about dark matter.

BERMAN: Immediately after the Big Bang, experts say the universe expanded rapidly but stayed mostly smooth and dark for about 100 million years.

Then things began to change. Scientists say that within that blanket of darkness, dark matter began to exert forces that pulled hydrogen, helium and lithium gases together to form stars.

THEUNS: "You may say, why care about the first stars in the Universe? But the first stars produce the first light in the Universe."

BERMAN: That is Astronomer Tom Theuns at Britain's Durham University. Writing in the American journal "Science," Theuns and his colleagues describe a way that those stars, which are billions of years old, may help today's scientists unravel part of the dark matter mystery.

It depends on whether those oldest stars are in long strings or clumped together.

The dark matter that existed soon after the Big Bang may have been either "warm" or "cold." Those are the terms astronomers use to describe how much energy the matter contained, or more simply, how fast its particles moved. The researchers developed a sophisticated mathematical model to show that stars would have clustered together in clumps under the influence of cold dark matter. In contrast, warmer dark matter would have produced stars in long strings, or filaments. Theuns says his theory may provide at least part of an explanation for the origin of the super-massive black holes at the center of some galaxies.

THEUNS: "So what we think is possible that is that in these filaments that you form in warm dark matter, if you form many stars along this filament, that you will get collisions between the stars. So, soon collisions between the stars will make up a star that are so massive that it cannot remain a star, it becomes a black hole. And once it becomes a black hole, it can grow very rapidly by swallowing these stars that are around."

BERMAN: Astronomers do not yet have telescopes that can see the distant stars that were formed some 13 billion years ago, when the universe was young, so even if Theuns' theory is correct, it still does not provide any immediate insight to the nature of dark matter, even though it suggests that dark matter may have had a crucial role in the arrangement of stars in the early universe. Jessica Berman, VOA News, Washington.

More space news now, a little closer to home.

The Japanese space agency Friday launched an unmanned probe to the moon. The long-delayed mission is set to orbit the moon for a year, collecting information about the moon's geography and structure and deploying two smaller satellites.

The moon may also be the target of private spacefarers aiming to collect a newly-offered $25 million prize.

The X Prize Foundation, which sponsored a $10 million space competition a few years ago, is upping the stakes with financing from Internet search giant Google. To capture the new prize you'll have to land a rover on the moon and send back high-quality pictures and other data.

The United Nations Food and Agriculture Organization held a special session in Rome this week to discuss the impact of climate change on world food security. Experts say higher temperatures and other climate changes threaten to disrupt agriculture around the world, with developing countries, as usual, expected to fare the worst. In Washington meanwhile, a new country-by-country analysis describes in detail the impact climate change is likely to have on global agriculture. Rosanne Skirble has our report.

SKIRBLE: By the end of this century, if current trends continue, world agriculture will be in serious trouble, according to economist William Cline, senior fellow with the Center for Global Development and the Peterson Institute for International Economics. His new study, "Global Warming and Agriculture," tells the story:

CLINE: "The key summary figures are that global agriculture potential could fall by about five to 15 or 20 percent as a result of global warming, if nothing is done by the 2080s. But secondly, that would mask a much deeper loss, something like 30-40 percent in India, for example, and something like 20 percent or more in Africa and Latin America, because there would be some countries, some areas, where there could actually be some gains."

SKIRBLE: The new study features estimates for 100 countries, regions and sub-regions. Cline says developing nations will be hardest hit simply because of their location.

CLINE: "Countries that are closer to the Equator have higher temperatures already, and those temperatures are closer to or maybe already beyond the best temperatures for agriculture. And as they heat up they get into ranges that are beyond the tolerance levels for the crops."

SKIRBLE: While India will experience major losses in agricultural capacity, China and the United States, which are in similar latitudes, will suffer less. Other countries like Sudan and Senegal could face agricultural collapse, with estimates of more than 50 percent decline in food production.

Some analysts say increased atmospheric carbon might actually boost plant production in some regions. But Cline says it's risky to assume that such gains could make up for losses elsewhere.

CLINE: "In particular I estimate that with a bit more than twice as much carbon dioxide in the atmosphere as we have now, you would get something like a 15 percent increase in the agricultural yields. But that cannot be counted on. So a prudent approach is also to look at what would be the estimate if there is no carbon fertilization at all."

SKIRBLE: Cline's detailed country estimates are based on computer crop and weather models that link price data with temperature, rainfall and soil type. He says that while his results are consistent with reports by the United Nations' International Panel on Climate Change, the forecast may be optimistic in projecting food production declines.

CLINE: "Because it does not include damage from increased insect pests. It does not include damage from increased incidents of very severe weather such as floods and droughts."

SKIRBLE: Cline argues for aggressive emissions controls. He targets that message to policy makers in industrialized countries, but also to leaders in developing nations who have been reluctant to cap their countries' global warming emissions.

CLINE: "I think that this study might help [with the] refocusing of that attitude to recognize that their public is at jeopardy as well. So that then begins to get those policy makers to think, for example, that maybe it does make sense to levy some sort of a tax on carbon-based energy, use the revenue of that tax to do lots of other good things, like pay for their fiscal deficits, which can sometimes be a problem in those countries, but also to develop alternative forms of energy."

SKIRBLE: These and other options were on the table at the FAO meeting in Rome, where delegates called agriculture both a 'victim and a culprit' of climate change scenarios. Global agriculture accounts for more than 30 percent of the heat-trapping greenhouse gases in the atmosphere. Experts say farming systems must be better managed to emit less, even as farmers take steps to adapt as well as they can to the earth's changing climate. I'm Rosanne Skirble.

Time again for our Website of the Week, when we showcase interesting and innovative online destinations.

This week, it's a brand new site aimed at providing information to help improve the quality of drinking water around the world. It's called Safe Drinking Water Is Essential, and that pretty much explains the mission. Water expert Dr. Peter Gleick, a member of the site's scientific steering committee, says it provides a variety of tools to help.

GLEICK: "There's an atlas that provides basic data. There's information on the sources of water themselves, as you've seen; on contamination of water; on old ways and new ways of treating water resources. Old and new ways of distributing water. All of those things are going to be key for bringing solutions to bear."

The site, at, also provides case studies, profiling a desalination plant in Tunisia and describing arsenic contamination of water supplies in Bangladesh, to take two examples. And, as you might expect from a website produced by the U.S. National Academy of Sciences, all the information has been carefully checked by experts.

Although the website is the cornerstone of the Safe Drinking Water Is Essential campaign, they are also distributing a version in compact disk format, so areas that don't have web access can still get the information on CD-ROM. Hamé Watt, a water consultant and former professor, originally from Senegal but now working in the U.S., says the information will be especially useful in developing countries.

WATT: "So we are very happy about the website, and I think it'll be very useful for the people in the field, whether they are drilling wells or building water towers or doing any other planning, I think it will be very, very useful. And especially [because] it is in many languages, in French and Spanish and Arabic and so forth."

Also Mandarin Chinese and, of course, English.

As the site reminds us, contaminated water is responsible for some 1.8 million deaths each year from diseases like cholera that are spread by unsafe water. The difference between clean and dirty water can literally be the difference between life and death.

So dive in to this brand new and important resource on safe water supply:, or get the link from our site,

MUSIC: Wynona Carr — "'Til the Well Runs Dry"

It's VOA's refreshing science and technology magazine, Our World. I'm Art Chimes in Washington.

Cancer patients have long complained of fatigue caused by chemotherapy treatments for their disease. And many patients say that the fatigue and other symptoms persist long after their chemotherapy has ended. These reports are what researchers call anecdotal. Now, new research finds scientific evidence to support those anecdotal complaints.

HOBAN: Researcher Paul Jacobsen and colleagues at the Moffit Cancer Center in Florida studied 220 women who had completed cancer treatment. They asked them about their symptoms six months after the women had completed their chemotherapy.

JACOBSEN: "We all experience fatigue to some degree. So we went out, recruited women who were the same age, who lived in the same geographic areas as the breast cancer sample. And we did direct comparisons of the women with breast cancer and their age- and geographically-matched comparison subjects."

HOBAN: Jacobsen says he and his colleagues asked all the women to note how many days each week they experienced fatigue and had them rate their fatigue. The former patients had much more fatigue.

JACOBSEN: "We compared them to the controls, and what we found was that — let's just take number of days fatigued in the past week. We found that about 19 percent of the controls scored above what I would say would be clinically significant level for fatigue. Whereas, we found that 28 percent of the patients were still reporting that severity of fatigue six months out [after therapy was ended]."

HOBAN: Jacobsen says their survey found that women who stayed active during chemotherapy were better able to manage their fatigue during and after treatment. But Jacobsen says the researchers were surprised that the treated cancer patients — whether they exercised or not — reported so much more fatigue than the women in the control group who had not received chemotherapy.

JACOBSEN: "And in fact, we really didn't expect it to be this severe even six months out. We're continuing to follow these same women. We are now about to interview them about three years out from the completion of treatment. And it'll be interesting to see whether or not the fatigue has persisted even that long."

HOBAN: Jacobsen says those results will be published in about a year. The current study is published in Cancer, the journal of the American Cancer Society. I'm Rose Hoban.

Finally today, as promised, here's a story about near-extinction, recovery, and the genetic clues that are helping scientists understand the history of one of the ocean's biggest creatures.

In the nineteenth century, intensive hunting brought the gray whale close to extinction. Although whales in the western Pacific are still endangered, protection efforts in the eastern Pacific seemed, at first, to have brought the population there back to pre-whaling numbers. Conservationists regarded the gray whale's comeback as a great success story.

But now, research reported this week in the Proceedings of the National Academy of Sciences is raising questions about the recovery. Using a genetic analysis, scientists say the whales may have recovered from near-extinction, but their population is still much smaller than it once was. And, as we hear from Véronique LaCapra, the finding suggests the world's oceans may no longer be able to support such a large number of the graceful leviathans.

LaCAPRA: The gray whales of the eastern Pacific have been considered one of the great success stories of species recovery. After being hunted to near-extinction by commercial whalers, their current population is now estimated to be about 22,000. But new data on historic gray whale populations are forcing scientists to reassess how well these whales have recovered:

ALTER: "It's been difficult to estimate how many animals there used to be before whaling started."

LaCAPRA: Liz Alter is a Ph.D. student at Stanford University in California, and the lead author of a study that used genetic analysis to assess the historic population size of gray whales.

ALTER: "The history of a population is in a sense written in its DNA, because larger populations have much more genetic variability than smaller populations. So by measuring genetic variation in a population today, we can say what the average, long-term, historical size of that population was."

LaCAPRA: Earlier estimates of the pre-whaling population had been based largely on historical accounts from commercial whalers and were in the same range as the current average population estimate of 22,000.

ALTER: "We found that genetic diversity in gray whales today is much higher than you would expect for a population of roughly 22,000, and instead is more typical of a population size of between 78,000 and 117,000. So that indicates to us that there once were many more gray whales, as many as three to five times more in the Pacific Ocean than there are now."

LaCAPRA: That difference between historic and current gray whale populations could have serious implications for other marine species, as well, according to Stanford biology professor Steve Palumbi, a co-author of the study. He says gray whales play a key role in the ocean ecosystem — through their unusual feeding behavior:

PALUMBI: "They're like marine bulldozers. They feed by jamming themselves into the bottom and then scooping up a big mouthful of the sediments and clays and muds, and sieving out all that they slowly rise to the surface with this big mud-plume following behind them."

LaCAPRA: From the mud that they've scooped up from the ocean floor, the whales filter out and eat thousands of small, shrimp-like crustaceans. They also lose a lot of them, along the way:

PALUMBI: "They're sort of messy eaters. When they rise to the surface, a lot of their food escapes and they're essentially bringing these bottom crustaceans up to the surface, where seabirds can get them."

LaCAPRA: In fact, at their historic population levels, gray whales may have stirred up enough crustaceans to support as many as a million seabirds.

The new whale numbers may also help to explain more recent changes in the species' population dynamics. Between 1999 and 2001, gray whales began starving to death. Scientists hypothesized that the population might have recovered too well — that there were now more gray whales than the ocean could support. Liz Alter says their new study provides evidence for an alternative explanation, that the problem may lie in the ocean environment itself:

ALTER: "Our finding suggests that in fact the ocean in the past has supported many, many more whales than there are now, and so we might be better off investigating the large-scale ecosystem level changes that we know are occurring on their feeding grounds, possibly due to climate change."

LaCAPRA: Other research has suggested that climate change may have reduced the gray whale's food supply, by warming deep arctic waters.

The eastern Pacific gray whale population has made a substantial recovery, coming back from near extinction. But according to Alter and Palumbi, the gray whales still need protecting, and more research on their complex ocean habitat will be needed to ensure their continued survival. I'm Véronique LaCapra.

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That's our show for this week. We're always interested in your comments or your science questions. Email us at Or use the postal address -

Our World
Voice of America
Washington, DC 20237 USA.

Rob Sivak edited the program. Eva Nenicka is the technical director. And this is Art Chimes, inviting you to join us online at or on your radio next Saturday and Sunday as we check out the latest in science and technology ... in Our World.