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Vol. LVII, No. 13
July 1, 2005

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STEP Session Describes Health Challenges of a Growing Population

On the front page...

It's not every day that you go to a session on the NIH campus and hear about melting ice in Greenland, population growth trends and international markets. But that's exactly what attendees heard at the recent STEP forum "Food for Thought: Sustaining the Global Population." The health of a growing world population is going to depend on strong cooperation between many different communities.

Lester Brown, president of the Earth Policy Institute, led off with a wide-ranging talk that provided a framework for the forum. While the world's population continues to grow, he said, world grain stocks are now at about their lowest level in 30 years. Two major challenges to meeting the growing demand in the coming years will be falling water tables and rising temperatures.


  Lester Brown addresses STEP forum.
Underground aquifers are recharged by precipitation, but many nations are pump-ing their aquifers faster than they're being recharged. Half the world's people now live in countries where water tables are falling, Brown said, yet few governments seem to be paying attention. "What's happening in Asia today with water is very similar to what happened in Africa with the HIV virus 15 years ago."

Rising temperatures will also strain food production, Brown explained. The Earth's average temperature is clearly rising, and heat interferes with crop production, particularly with the pollination process. For each degree Celsius rise in temperature above the norm during the growing season, Brown said, there is a 10 percent decline in grain yields.

But it's more than just the direct effect of temperature that's important. Brown explained that when sea ice in the Arctic melts, less sunlight gets reflected back into space and the sea absorbs more heat. "That is important," he said, "because of its effect on Greenland and the enormous amount of ice in Greenland." If that ice melted, it would raise the sea level 23 feet, Brown argued. That would not only inundate many of the world's coastal cities; it would also inundate many of the rice-growing areas in Asia.

Brown said that economic trends are placing an additional strain on world food production. Using water to expand industrial output can yield a return up to 70 times greater than using it to produce grain. Industrial development creates a more profitable use for cropland as well. It also draws people from the countryside and away from labor-intensive farm work. This is what happened in Japan, he explained, and more recently in China, accounting for recent drops in grain production there.

Dr. Joel E. Cohen, who heads the Laboratory of Populations at the Rockefeller and Columbia universities, followed Brown's talk by explaining global population trends in more detail. We can expect to add 2.6 billion more people to the world by 2050, he said. In comparison, the entire population of the Earth was only 2.5 billion in 1950. This works out to one city of a million people added each week for the next 45 years.

But while population growth is a problem, Cohen said, starvation and malnutrition are caused by more than just population growth. In fact, the world population growth rate peaked between 1965 and 1970 and has fallen by one-third from its high. The world now produces more than enough to feed everyone alive today an adequate diet. Cohen reviewed the famine in Sudan in the 1990s as a specific example that people have interpreted as a population problem. "Does Sudan have a population problem?" he asked. Many other countries have been able to deal with their explosive population growth. Cohen described a range of environmental problems, crop management failures, market failures, and various political and cultural factors that all contributed to the famine in Sudan. "To look at this as a population problem alone misses the complexities," he said. "Population problems intersect with the environment, economics and culture."

Speakers at the recent STEP seminar on sustaining global population were (from l) Lester Brown, Dr. Rebecca Nelson, Rajul Pandya-Lorch and Dr. Joel E. Cohen.

Cohen pointed out that the demands of food production from a growing global population create health problems beyond producing and distributing enough food. "You can think of the human species as embedded in a food web of relationships with the species that it eats and the species that eat it," he explained. The species that eat us now aren't so often lions and tigers anymore, he said, but infectious diseases such as malaria, tuberculosis and schistosomiasis.

One of his research interests is Chagas disease, which currently infects millions in South and Central America. People in Argentina keep chickens in their bedrooms to protect them from predators, Cohen explained. Insects feed on those chickens and also bite people and dogs, transmitting the parasite that causes Chagas from dogs to people. "There's a close connection between the food production and the infectious disease."

Another example of this connection is avian influenza in Asia, which has been of global concern recently. "The taking away of wetlands for rice lands," Cohen explained, "meant that migratory wild fowl had to use rice fields for their stopovers and defecated into the water, transmitting avian influenza to domestic fowl." People then catch the disease from their domestic fowl. "So there's such an intimate connection between what we eat and what eats us," he said. "We can't get away from that connection."

Cohen explained how factors beyond having enough food affect the health of a growing world population. Dr. Rebecca Nelson, program director for the McKnight Foundation Collaborative Crop Research Program, took up the topic by describing the recent shift in mentality in the international agricultural research community. Until recently, she explained, researchers were focused mostly on producing more food. They are now asking, "Is it really production that we're trying to achieve or is it healthier children?"

Nelson said there's been a shift from production- oriented research toward nutrition-oriented and livelihood-oriented research. She gave as an example a project in East Africa to address vitamin A deficiency. Breeding sweet potatoes to be rich in vitamin A yet culturally acceptable was a serious challenge. "People don't necessarily love the fact that you've just turned their staple crop orange," she said. But when research programs are combined with nutrition education, they can effectively improve the health of the people they are intended for.

"You need an integrated approach if you want to make a change," Nelson said. "We ignore culture and preference at our own peril." In this case, she said there was an impressive collaboration between the agriculture, health and religious sectors. "They find that it's acceptable to turn their food orange if and only if they understand that it's good for their children," she explained.

Nelson gave many other examples of research programs guided by local and regional challenges. Traditional breeding techniques, newer transgenic technologies and other innovations like rotating crops throughout the growing season are all being employed to increase food security in areas with poor soils and harsh environmental conditions.

Rajul Pandya-Lorch of the International Food Policy Research Institute rounded out the session by outlining the economic challenges to food security. Availability of credit and access to markets are just as important to food security as increased food production, she explained. Health is also a major factor. "Health, agriculture, poverty and hunger go hand in hand," she said.

Pandya-Lorch argued that while the world has focused on HIV/AIDS, malaria and tuberculosis are also devastating health crises; even less acknowledged are those health conditions that don't lead to mortality but sap people's health. "Chronically ill people are people who cannot take advantage of whatever technological advances you provide to them," she said. "You cannot blame people for being poor and food-insecure if you don't also address the health issues," she stressed, thus highlighting NIH's role in this picture.

The speakers described creative ways that researchers and policy makers are addressing the problems they had described. Pandya-Lorch spoke about the renewed international focus on investments in education, social services and infrastructure. Nelson spoke about farmer participation in a range of research programs, both to improve local crops and to find creative ways to bring new crops into stressed areas. Brown described innovative dairy marketing cooperatives in India, efficient beef production methods in China and an ingenious method of aquaculture that has significantly boosted China's output in an efficient, environmentally friendly way.

Pandya-Lorch stressed, "There is nothing that prevents us from being food secure if we put our will to it and our resources to it."

She observed of the effort in Africa, "You're finally beginning to see a critical mass of people from various sectors engaging in these issues. It is not just little pockets anymore." The research communities, policy communities, media and various civil groups are all working together to combat hunger and poverty, she said. "And that gives me more hope than I've ever had before."

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