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05/28/93

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Humanity confronted by 'food trap,' scientists assert

STANFORD -- A new article by Stanford University ecologist Paul Ehrlich and two co-authors warns that humanity is facing a very serious "food trap" - the continuing growth of the population that needs to be fed damages the very systems that are relied upon to produce the food.

"Complacency about the security and abundance of the world food supply, even in the near future . . . is unjustified, especially if the environmental dimensions of the agricultural enterprise are carefully considered," Paul and Anne Ehrlich, along with Gretchen Daily of the University of California-Berkeley's Energy and Resources Group, wrote in an article published May 28 in Population and Development Review.

People "must somehow balance the costs of inadequate levels of food production . . . against the environmental costs of pushing closer to the biophysical limits of food production," the Ehrlichs and Daily wrote. The costs of pushing those limits, they said, include a diminishing of the earth's capacity to produce food.

"Expansion of global grain production (the basis of the human food supply), which kept well ahead of population growth between 1950 and 1984, has failed to do so since then," they wrote.

Yet, they found, "Providing sufficient food both for people now undernourished and for projected additions to the population in the next half-century . . . would require a near-tripling of food production by 2040." Thus, another spurt in production rivaling that which occurred from 1950 to 1984 is needed, they found. But, they asked, from where will it come?

"Most of the readily available opportunities for substantial expansion of world food production (including the opening of new fertile lands, developing fertilizer-sensitive 'miracle' strains of major crops, and applying synthetic fertilizer) have been taken," they wrote. Also, they found, the best land for irrigation is already being irrigated.

In place of those earlier opportunities for expansion, agricultural scientists now find themselves confronting a series of problems that they realize will not be easily overcome. These, the Ehrlichs and Daily wrote, include:

  • Losses of farmland to other uses because of population pressures and limits to the amount of suitable new land that can be brought into production.
  • Limits to freshwater supplies.
  • Erosion and degradation of soils.
  • Declining genetic diversity of crops.
  • Reduced yields from a variety of air pollutants that are toxic to crops.

Also, they found, diminishing returns to the application of fertilizers and little-understood "caps" on yields in rice and, possibly, other crops, are sources of concern.

The research team found that increased ultraviolet radiation, caused by thinning of the ozone shield, also can be very damaging to crops, and "rapid climate change almost certainly represents an even greater threat to [future] food production than ozone depletion.

"The prospects for humanity's other major food source, oceanic fisheries, are also problematic," the Ehrlichs and Daily wrote. Fish catches are already near the theoretical maximum that can be sustained, and many fisheries are clearly in decline.

"The current pattern is one of overexploitation of stocks to the point of collapse, followed by shifts to exploitation of new stocks, generally in more remote regions or of less desirable species," they wrote. "The rising costs of harvesting fishes are reflected in the prices of seafood, which have doubled in real terms since 1955."

Besides the obvious "escape routes" from the food trap (halting population growth, reducing poverty to increase economic access to food, abolishing counterproductive agricultural subsidies, and generally improving food distribution), the scientists called for raising much higher on the political agenda programs to expand food production.

"Since the most rapid population growth and the largest deficits in food production per person are both found in developing countries, their agricultural sectors must be the chief focus of efforts to address food shortages," the researchers wrote.

The Ehrlich team recommended paying particular attention to ecologically sound ways of increasing food production for domestic consumption (rather than cash crops for export) and to substituting more productive crops for less productive ones (as the Chinese, for example, have done in switching from rice to potatoes and corn in cooler regions).

Finally, they emphasized the critical need for increased protection of the natural ecosystems that support agriculture. They also called for an aggressive effort to reverse the staggering losses of soil and freshwater, and to restore the productivity of degraded lands, which currently constitute nearly 20 percent of the Earth's vegetated surface.

In their opinion, a human population sustainable in the long run will number fewer than today's 5.5 billion. The team also said that the 10 billion or more people the Earth is faced with supporting in the near future "cannot be nourished even temporarily unless far greater attention and resources are directed to [developing] environmentally sound agricultural systems and improving food distribution."

Paul Ehrlich, professor of biological sciences and author of The Population Bomb and co-author, along with Anne Ehrlich, of The Population Explosion, is the Bing Professor of Population Studies.

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