The turkey and ham many are eating this holiday season don't just appear magically on the table. Most are the end product of an increasingly global, industrialized system that is resulting in costly environmental degradation. Better understanding of the true costs of this resource-intensive system will be critical to reducing its negative effects on the environment, says an interdisciplinary team of researchers led by Stanford University's Rosamond Lee Naylor, Walter Falcon, and Harold Mooney.

"Losing the Links Between Livestock and Land" appears in the Policy Forum in the Dec. 9 issue of Science. It represents a synthesis of research by professors at Stanford University, the University of Virginia, the University of California at Davis, the universities of Manitoba and British Columbia in Canada, and the United Nations LEAD (Livestock Development and Environment) program within the Food and Agricultural Organization of UN.

"Sixty years ago, the link between the livestock production and consumption was much more clear and direct, with most consumers getting their meat and dairy products from small, family-owned farms," says lead author Naylor, an economist. Co-author Falcon agrees. "When I was growing up in Iowa, almost all farmers kept both chickens and pigs."

Today, meat consumption has sky-rocketed, and large-scale intensive livestock operations provide most of those products, both in the U.S. and around the world.

Particularly striking is the growth in demand for meat among developing countries, Naylor notes. "China's meat consumption is increasing rapidly with income growth and urbanization, and it has more than doubled in the past generation," she says. As a result, land once used to provide grains for humans now provides feed for hogs and poultry.

Numerous factors have contributed to the global growth of livestock systems, Naylor notes, including declining feed-grain prices; relatively inexpensive transportation costs; and trade liberalization. "But many of the true costs remain largely unaccounted for," she says. Those costs include destruction of forests and grasslands to provide farmland for corn, soybeans and other feed crops destined not directly for humans but for livestock; use of large quantities of freshwater; and nitrogen losses from croplands and animal manure.

Nitrogen losses are especially problematic, says James Galloway of the University of Virginia. "Once nitrogen is lost to the atmosphere or to water, it can have a large number of sequential environmental effects. For example, ammonia emitted into the atmosphere can in sequence affect atmospheric visibility, forest productivity, lake acidity and eventually impact the nutrient status of coastal waters."

Naylor cited Brazil as a specific example of the large impact on ecosystems and the environment. "Grasslands and rainforests are being destroyed to make room for soybean cultivation," she said. The areas are supplying feed to the growing livestock industry in Brazil, China, India and other parts of the world, leading to "serious consequences on biodiversity, climate, soil and water quality."

Naylor and her research team are seeking better ways to track all costs of livestock production, especially the hidden ones related to ecosystem degradation and destruction. "What is needed is a re-coupling of crop and livestock systems," Naylor said. "If not physically, then through pricing and other policy mechanisms that reflect social costs of resource use and ecological abuse."

Such policies "should not significantly compromise the improving diets of developing countries, nor should they prohibit trade," Naylor added. Instead, they should "focus on regulatory and incentive-based tools to encourage livestock and feed producers to internalize pollution costs, minimize nutrient run-off, and pay the true price of water."

She cited efforts in the Netherlands to track nitrogen inputs and outputs for hog farms as one approach. In the U.S., the 2002 Farm Bill provided funds for livestock producers to redesign manure pits and treat wastes, but she notes that much greater public and private efforts are needed to reduce the direct and indirect pollution caused by livestock.

In the end, though, it may be up to consumers to demand more environmentally sustainable approaches to livestock production. "In a global economy with no global society, it may well be up to consumers to set a sustainable course," she added.

Seed funding for the research was provided by the Woods Institute for the Environment, which supports interdisciplinary approaches to complex environmental issues. Naylor, Falcon and Mooney are affiliated with the institute and with the Center for Environmental Sciences and Policy in Stanford's Freeman Spogli Institute for International Studies.

In addition to Naylor, Mooney and Falcon of Stanford and Galloway of Virginia, co-authors are Henning Steinfeld of the United Nations Food and Agriculture Organization; Galloway; Vaclav Smil, University of Manitoba; Eric Bradford, University of California at Davis; and Jacqueline Alder, University of British Columbia.

SEATTLE - There are a billion hungry people in the world. Fifteen thousand children-the equivalent of five times the victims of the World Trade Center bombings-die each day of hunger. Yet it doesn't have to be this way. We can end hunger-if we make a commitment to doing so. The new one-hour documentary Silent Killer: The Unfinished Campaign Against Hunger shows how it can be done. Shot on location in the United States, South Africa, Kenya, Rome, Mexico and Brazil, Silent Killer examines both the problem of hunger and solutions. The documentary and its companion Web site (www.SilentKillerFilm.org) will provide viewers with inspiration and information to become part of the effort to end hunger.

Produced by Hana Jindrova and John de Graaf (Affluenza, Escape from Affluenza), in association with KCTS/Seattle Public Television, Silent Killer will air on several California public television stations as follows:

KTEH/ San Jose: Sunday, October 16 at 5:00 p.m. (please confirm).

KOCE/ Huntington Beach: Sunday, October 23 at 4:00 p.m.

KQED/ San Francisco: Wednesday, November 2 at 11:00 p.m., repeating on

KQED Encore (Digital Channel 189), Thursday, November 3 at 10:00 p.m.

KVCR/ San Bernardino: Thanksgiving evening, Thursday, November 24 at 8 p.m.

KVIE/ Sacramento: Airdate and time to be announced.

KCSM/ San Mateo: Airdate and time to be announced.

(For all other stations, please check local listings).

Narrated by National Public Radio's Scott Simon, the film begins in South Africa's Kalahari Desert, where razor-thin Bushmen use the Hoodia cactus to fend off hunger. But now, a drug firm has patented the Hoodia's appetite-suppressant properties and is using it to make a diet product for obese Americans and Europeans. Hoodia is a metaphor for a world where some people die from too much food, but millions more die from too little.

We discover how serious the problem is in Kenya as we meet Jane Ininda, a scientist who is trying to make agriculture more productive in her country, while her own brother, Salesio, barely survives the drought, poor soils and pests that constantly threaten his crops. Through powerful stories, we come to understand the dimensions of the hunger crisis.

At the World Food Summit in Rome, we learn how activists have been working to end hunger since President John Kennedy declared war on it in 1963. But today, America's commitment to food security is less clear. In fact, world financial commitments to hunger research are now in decline.

But Silent Killer does not leave viewers feeling helpless. A visit to Brazil finds a nation energized by a new campaign called FOME ZERO-Zero Hunger. In the huge city of Belo Horizonte, we meet a remarkable leader and see how, under the programs she supervises, the right to food is guaranteed to all. In the countryside, we are introduced to the Landless Peasants' Movement, which is giving hope to millions of hungry Brazilians.

Can we end hunger, or will it always be with us? Why should we try? What will it take? What are we doing now? Can biotechnology play a role, and if so, how? Is hunger just a problem of distribution, or do we still need to produce more and better crops? These are the questions considered in this exquisitely photographed documentary.

EXPERTS featured in Silent Killer: The Unfinished Campaign Against Hunger and available for press interviews include:

David Beckmann - President, Bread for the World. Since 1991, Reverend David Beckmann has served as president of Bread for the World, a Christian group that lobbies the U.S. government for policy changes to end hunger in the United States and around the world.

Per Pinstrup-Andersen - World Food Prize Laureate 2001. A native of Denmark, Per Pinstrup-Andersen is the H.E. Babcock Professor of Food, Nutrition and Public Policy at Cornell University. He also serves as the chairman of the Science Council of the Consultative Group on International Agricultural Research.

Chris Barrett - Development Economist, Cornell University. Dr. Barrett is a professor of applied economics and management at Cornell University. His focus is on rural communities, primarily in Africa, concentrating on the dynamics of poverty, food security and hunger.

Walter Falcon - Development Economist, Stanford University. Dr. Falcon is the Farnsworth Professor of International Agricultural Policy at Stanford University (emeritus), co-director of the Center for Environmental Science and Policy, and former director of the Stanford Institute for International Studies.

PROGRAM TIE-INS: October 16 is the 25th observance of World Food Day-a worldwide event designed to create awareness, understanding and year-round action to alleviate hunger. (See www.worldfooddayusa.org.) In addition, October 24 is the 60th anniversary of the founding of the United Nations and its first agency, the Food and Agriculture Organization (FAO).

CREDITS: Silent Killer was produced by Hana Jindrova and John de Graaf in association with KCTS/Seattle Public Television and is narrated by NPR's Scott Simon. Writer: John de Graaf. Photographers/Editors: Diana Wilmar and David Fox. Composer: Michael Bade. Executive Producer: Enrique Cerna, KCTS. Funding was provided by The Rockefeller Foundation.

DISTRIBUTOR: Silent Killer is presented nationally by KCTS/Seattle Public Television and is distributed by the National Educational Telecommunications Association (NETA).

WEB SITE: See www.SilentKillerFilm.org for more information about the film, including a full transcript, in-depth interviews with film characters and experts on hunger, a guide for teachers, a list of hunger facts and myths, a detailed "Take Action" section and additional resources. Color images from the film are posted on the site for press use, along with an online press kit.

I begin with a proposition. There are a great many pressing problems in the world. There is population growth and economic development, with attending pressures on resources - including food and that other essential, water. There is a continuing global security crisis, augmented by the rise in terrorism. There is the chronically inequitable distribution in resources between the rich nations of the North and the poor nations of the South. And there is the steadily growing body of evidence for a major reorganization of the global climate regime.

My proposition is that the last of these is the most serious threat - not only because it will profoundly affect the lives of our children and our grandchildren in a direct way, but also because it will interact powerfully with every single one of the other problems I have listed.

Let me begin with the science underlying climate change. Last week I helped organize a symposium and briefing session on climate science for press, policy-makers, and the public, supported by the Hewlett Foundation and with co-sponsorship from the Conference Board. We had ten of the most distinguished climate scientists in the United States, led off by Sherry Rowland, the Nobel Laureate in Chemistry. The purpose was to make a careful assessment of the science - what we know for sure, what we think likely, and what are interesting but unproven possibilities.

So here is a short summary of what we know. General Circulation Models - climate models that take into account variations in the sun's energy, volcanic activity, and other natural phenomena - explained fluctuations in average global temperature very well over most of the past thousand years. But for the past hundred years, these same models faithfully reproduce global temperature history ONLY if they include the greenhouse gases - carbon dioxide, methane, and chlorofluorocarbons - that are by-products of human economic activity. That is why the average temperature of the globe has risen by about one degree F, and the sea level has risen by between 10 and 20 cm., in the last century. The primary causative agent is carbon dioxide, which in preindustrial times was about 280 ppm/v and has now reached 380ppm/v. It is rising continually as the activities that produce it are proceeding on a business as usual basis. That is because the failure of the Kyoto protocol - a failure both because its targets were inadequate, and also because they were unattainable by many of the participating nations - has left us without any basis for meeting the goals of the 1992 Framework Convention on Climate Change. Just to remind us, the US is a signatory and a party to that agreement, under which we are committed to limit atmospheric concentrations of greenhouse gases to avoid "dangerous anthropogenic interference with the climate system."

Why, a dozen years later, is there some doubt about the dangers of this interference? The C02 we add to the atmosphere will stay there; its average residence time is a century. There is no disagreement about whether average global temperature will rise; it will. The scientific debate is about how much. For the future we depend again on the General Circulation Models. It's reassuring that when applied to past climates in "back-casting" efforts, like the example I gave a moment ago, these actually predict climate history so accurately. Perhaps more interesting, they regularly somewhat underestimate the magnitude of the real climate changes - that is, Nature regularly turns out to be harsher than the models suggest. Projecting the models into the future, the Intergovernmental Panel on Climate Change, and an evaluation by the National Academies prepared at President Bush's request, estimate that by the end of this century, the increase in average global temperature will be between 1.4 and 5.8 degrees Centigrade.

Why such a range? These models, like most, contain some uncertainties. Some of these are scientific: how increased cloud cover might affect the outcome, since clouds can either cool the climate by reflecting sunlight from above, or warm it by trapping heat that is leaving from below; how changes in the earth's albedo due to melting ice might accelerate heating, and so on. Aerosols produced by volcanic eruptions have a cooling effect, as the eruption of Mt. Pinatubo did in giving us two unusually cool years in the early 90's. Other uncertainties are economic and social: we don't know how national policies and international agreements will serve to restrain the amount of greenhouse gases we are adding.

These uncertainties - about half due to the models themselves, and the rest to social and economic unknowns -- have provided arguments for those who prefer to postpone economically difficult approaches for controlling greenhouse gas emissions. But it is important that even at the very lowest estimates, there will be substantial changes in the nature of human life on the only planet we currently occupy. The rather modest impacts of the past century have already produced profound changes in regional climate dynamics. Substantial ice-sheet melting and retreat is taking place both in the Arctic and in the West Antarctic ice sheet. In the Arctic, where climate warming has been extreme, sea ice is sharply diminished and rivers become ice-free much earlier. Low latitude mountain glaciers are shrinking; the famous snow-capped summit of Kilimanjaro will be bare within fifteen years, converting hundreds of old African safari shots into historic treasures.

Biological cycles are experiencing the effects of warming, with upward extensions of the range of Alpine flora and advances in the time of flowering or breeding by an average of 5 days per decade. The models have all also predicted more frequent and severe weather events, and we have had heat waves in the upper Midwest and Paris, accelerated beach erosion on coasts all over the world, and disastrous floods and landslides in Central America.

That is now, but of course we are more interested in the future. What the models tell us unambiguously is that the climate system is headed for further disruption. The standard scenario foresees a steady, ramp-like increase in average global temperature, with a concomitant rise in sea level, but records of past climate tell us that it is riddled with abrupt changes - something that the models fail to predict well. A possible alternative involves a change in major ocean circulation patterns - especially in the North Atlantic, where a clockwise gyre brings warm equatorial water up via the Gulf Stream. As it flows Northward and then crosses Eastward, it is cooled by the atmosphere, becomes more saline through evaporation, and then sinks to return as a cold deep current. If large discharges of fresh meltwater or rain made this water less dense, it could fail to sink and thus disrupt the entire cycle.

A fictionalized version of such a scenario appears in the disaster film "The Day After Tomorrow," which you should see only for amusement. Beyond that silliness lies a real prospect that a gradual change in average global temperature could intercept the threshold for some non-linear, dynamic process, triggering abrupt changes in either direction. Of course there is uncertainty: we are engaged in a large-scale, uncontrolled experiment on the only planet we have.

Let's consider some collateral impacts. A group of us at Stanford was asked by the Carnegie Commission on Preventing Deadly Conflict to look - among other things -- at ways in which environmental change might alter the circumstances under which human populations might be placed. Climate change was an important variable. One example we looked at was the impact of sea level rise, along with storm surges from extreme weather events, on the Ganges-Brahmaputra delta. Flood disasters already occur there regularly. 15 million people live within 2 meter above sea level, and are vulnerable to abrupt displacement. We know they will have to go somewhere; in the past they have fled in much smaller numbers to Bengal. The security problems arising from a massive influx of a traditionally hostile population, combined with an almost certain high level of cholera infection, are not difficult to imagine.

Water is a desperately important resource in most parts of the world, and drought is often followed by famine or emigration. Here in the US, warmer winters threaten mountain snowpacks and will soon demand the revision of interstate and international water allocation agreements. Maritime rivers are already undertaking management steps to deal with saline intrusions due to sea level rise or storm surges. In Great Britain, the barrier that protects London from occasional flooding of the Thames estuary is now being used six times a year compared to less than once a year in the 1980's.

Agriculture, of course, is the most essential of human activities. The regional distribution of global warming impacts may be at least temporarily kind to temperate-zone food production. But the models all predict an increased incidence of mid-continent droughts as climate change progresses, and we know that the American Midwest has in the past experienced droughts both deeper and longer than the one in the 30's that led to the Dust Bowl migrations. Irrigation is an answer to drought, but in the six High Plains states, dryland wheat production depends upon the Ogallala Aquifer, a buried ice-age storage well that is being so rapidly depleted that it is already unusable in its southern portion. And in the tropics, where people are poorest and capacity to adapt is minimal, the consequences of even modest warming will be far more serious.

Infectious diseases are spread by vectors, like the Anopheles malaria mosquito, that have their own patterns of reproduction, movement, and climate sensitivity. In parts of Africa where vertical topography dominates, warmer and rainier seasons cause malaria incidence to rise in higher-altitude locations. In a warmer and wetter world, more of the same can be expected.

So climate change is not an isolated problem. Instead, it is likely to interact with most of the other problems humans face all over the world. Thus I hope that this meeting will help encourage us to prepare a sound portfolio of risk-reducing measures. These will not, I must tell you, bring us out of the woods. Our destiny is partly built in -- to the heat that is already locked into our oceans, to the greenhouse gases that are already in our atmosphere and will increase by another 50% or more no matter what we do, and to the justified economic appetites of the developing world. What we will be talking about, it should be clear, are ways of limiting the damage to manageable levels, NOT preserving the status quo. We lost that years ago.

So the contemporary policy challenge amounts to a bet about risk: are the consequences of business as usual likely to entail costs greater than those of beginning to mitigate those consequences now? Other nations - the UK, several EU countries, and Japan - are making substantial commitments. Some industries - British Petroleum, Royal Dutch Shell, and Swiss Re, for example - have undertaken steps of their own. The insurance burden from the exploding rates of coastal erosion and storm damage has pushed the insurance industry to lead. If companies fail to participate in emissions reduction and join with others to resist such measures, questions are already being raised. If you believe so strongly that climate change is a myth, Swiss Re might say, then surely you won't mind a climate-related events exclusion from your Directors and Officers insurance policy.

But we can't count on voluntary actions, and the United States so far has only announced a long-range research program that, although it looks reasonable, makes NO current commitments to mitigate our contribution, about a quarter of the world's, to the global warming problem. We must have a more aggressive national policy to purchase insurance against this risk.

It will not be cheap. We have old, coal-fired power plants in this country; it may take subsidies to replace them with modern, less carbon-intensive facilities that run on natural gas. States like mine are already driving the transportation sector to ultra-low emission, and that may move the domestic industry in a positive direction. Some of us will have to give up our reflex opposition to nuclear power and begin comparing its risks realistically against those of global climate change. Although the room for alternative energy sources (photovoltaic, wind, geothermal) is limited, these options need encouragement. Energy conservation measures have, at several times in the past, turned economic predictions on their head by their success, and the right incentives could yield real benefits there.

The portfolio I have just described is needed, but will not be enough. We know that market-based mechanisms for emissions control can work, because they did in the 1990 Clean Air Act Amendments that limited SO2 emissions. The bill proposed by Senators McCain and Lieberman would mandate a cap-and-trade program for controlling carbon dioxide emissions. Similar systems are being considered by regional assemblages of states in the Northwest and the Northeast, and that may encourage the development of a national system - which could then build trading relationships with other nations that are moving toward similar regimes. A case for this approach is elegantly made in the Council on Foreign Relations Policy Initiative on Climate Change, by my colleague David Victor.

The United States is in a position of natural leadership here. It is the most powerful nation - and the world's leading producer of greenhouse gases. Plainly it is in its own national interest, in multiple ways, to reduce its consumption of fossil fuels. To see it failing in this most vital, globally sensitive matter is a national embarrassment.

Destruction of the World Trade Center on September 11th changed the lives of most Americans. It seems destined also to change the lives of most Pakistanis and Afghanis. Pakistan now finds itself in the middle, being squeezed on the one side by the United States and on the other by the Taliban faction in Afghanistan. No nation would choose to have either the U. S. or the Taliban as its enemy. Unless Pakistan is extremely lucky, it will have both.

I worked in Pakistan as an agricultural advisor during much of the 1960s, trying to help improve the productivity of the immense Indus River irrigation system. My travels took me into the catchment areas in the northernmost reaches of the country and into contact with the tribal groups and clans who are residents of that region. Although I no longer focus on Pakistan, I was not totally surprised to be contacted by a local television producer who was doing a feature story on that country. During the filming I was asked the question: "What is it that Americans just don't 'get' about the situation in Pakistan and Afghanistan?" What follows is what I wish I had said in reply.

Most Americans do not know of, much less understand, the 2500 years of (unsuccessful!) invasions that have taken place in that part of the world. They cannot fathom the roughness of the terrain in the undefined border areas between Pakistan and Afghanistan or the incredible fearlessness and toughness of the people of the region. Very few Americans understand the traditions, rights, and obligations within and among the local clans, many of whom migrate back and forth with the seasons across an invisible border. Nor can they really imagine the extent of poverty, especially in Afghanistan, where life expectancy is still only about 45 years.

At the regional level, most Americans do not understand the depth of the tensions that still exist between India and Pakistan, the continuing problem of Kashmir in that key south-Asia relationship, and the presumed military alliance between Pakistan and the Taliban in continuing scrimmages against India in Kashmir. They further do not understand the problems of governing Pakistan, a country with incredibly divisive regional tendencies, within the aegis of an Islamic Republic.

Finally, American do not grasp how the "on again-off again" nature of U.S.-Pakistan-Afghanistan relationships appears to many people on the other side--people who are literally born with inherited friends and sworn enemies. Within my professional lifetime, U.S. relationships have ranged from genuinely close cooperation, which prevailed during the time of Presidents J. F. Kennedy and Ayub Khan; to more distant cold-war relationships that generally pitted the U.S. and Pakistan against the U.S.S.R. and India; to the widespread American military and economic support given both Afghanistan and Pakistan during the U.S.S.R. invasion of Afghanistan in the late 1970s; to a post Cold War move away from Pakistan and toward India; to the virtual stoppage of all support following the recent atomic tests by both countries. In short, many Americans are ignorant about the culture and history of the region, and many Pakistanis and Afghanis are totally confused about America's loyalty.

I do not know whether the U.S. and its allies will "invade" this region in search of Osama bin Laden, or if that happens, whether the "war" will be massive or surgical. I hope, however, that the U.S. has distilled several lessons from the region's ancient and modern history.

First, the Afghani people will not be frightened into doing anything. They would not even understand the concept. The tribal customs and obligations with respect to enemies are unbending. The tribesmen are both fearless and patient--ask the British, who were defeated three times over the last two centuries, or the Russians who most recently met a similar fate within the past 20 years. No one should underestimate the Afghani's skills as fighters, especially on their home turf--which is mainly rocks and caves and hills and mountains. The dozens of foreign monuments honoring the dead along the Khyber Pass Road from Peshawar, Pakistan to Kabul, Afghanistan are a grim reminder of just how ferocious the frontier people have been to those whom they regarded as outsiders.

Second, the extreme fundamentalist groups within Islam are a minority that challenge moderate Muslims in the region even more than they challenge outsiders. Nevertheless, the U.S. and its allies will have only the narrowest range of military options against the extremists lest these actions put moderate Muslims into the camp of the fundamentalists.

Third, U.S.-Pakistan relations have never been more delicate than at this moment. By virtue of location, information, and capacity to infiltrate, Pakistan's potential contribution to a "bin Laden solution" cannot be overemphasized. How the U.S. gets Pakistan's cooperation without at the same time pushing the moderates into the welcoming arms of the extremists is a diplomatic, economic, and military problem of unbelievable proportions. Unfortunately, history provides no ready-made answer to this dilemma, and that is what truly worries me - not only for the U.S., but also for moderate Muslims throughout the world.