One Earth, One Future Our Changing Global Environment (1990) / Chapter Skim
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7. Food, Water, and Changing Climate
7. Food, Water, and Changing Climate
Pages 78-89
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From page 78... ...
Today, assuming equitable distribution to the 5 billion people all over the world, the earth certainly provides enough food for an adequate diet. This fact, however, conceals a distressing paradox: In recent years, although the earth produced record amounts of grains, half a billion people were seriously malnourished.
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From page 79... ...
Malthus thought that ultimately a shortage of food would be the limiting factor on population growth, but his predictions ctid not take into account the remarkable advances in our ability to produce food. THE GLOBAL HARVEST Taking the world as a whole, Lester Brown, in the WorIdwatch Institute's annual State of the World assessments, reports that grain production per person has climbed an impressive 40 percent between 1950 and 1984.
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From page 80... ...
-A -- -, ~ A 1988 study by Robert Chen and colleagues for the Alan Shawn Feinste~n World Hunger Program at Brown University estimated that even if food were equitably distributed (with nothing diverted to livestock) , the amount of food produced On 1985 an all-time record-could have provided a minimal vegetarian diet to about 6 billion people, a number we will exceed by the end of the century.
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From page 81... ...
Based on current projections for population growth and increases in per capita income, world demand for food in the middle of the next century couIct easily be 2 to 2.5 times the level of the mid-19SOs, according to calculations by William Easterling Ill and Pierre Crosson, both of Resources for the Future, and Martin Parry, of the Atmospheric Impact Research Group at the University of Birmingham in the United Kingdom. Crosson and his colleague Norman Rosenberg, also at Resources for the
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From page 82... ...
. The primary prospects for expanding food production are the potential for increasing yields on existing agricultural land through more intensive cropping, increased fertilizer use, and the development of more productive strains, and increased reliance on anct clevelopment of new methods for harvesting food from the oceans.
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From page 83... ...
But researchers, lacking knowledge about the regional distribution of climate changes, can only estimate where and by how much these shifts in productivity will occur. Scientists trying to simulate potential effects of global warming on agriculture rely on the same general circulation climate models (GCMs)
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From page 84... ...
For climate conditions produced by effective carbon dioxide doubling as projected by the GISS model, for instance, wheat yields increase by about one third in the central European region of the Soviet Union, where there is currently a short, coo! growing season.
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From page 85... ...
If the positive direct effects occur in the field, the combinations of increased growth and improved water use efficiency may help offset the negative effects of climate change on crops. WATER SUPPLY, IRRIGATION, AND THE HYDROLOGIC CYCLE One of the more generally accepted conclusions of the general circulation climate models is that as average global temperatures increase, the hydrologic cycle will speed up, increasing global precipitation.
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From page 86... ...
Gleick, of the Pacific Institute for Studies in Development, the Environment, and Security in Berkeley, California, identifies in the 1989 publication Greenhouse Warming: Abatement and Adaptation a seasonal effect for basins in the western United States In which changes in runoff patterns may alter the likelihood of flooding and the availability of water during such times as the peak irrigation season. Similar changes are predicted for China, Canada, and Europe.
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From page 87... ...
EPA and the U.N. Environment Programme, Martin Parry cites accounts of the Norse settlers in Greenland during the period between 1250 and 1500, the beginning of the Tithe Ice Age.
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From page 88... ...
Farmers in the Midwestern United States, for instance, after experiencing the 1988 drought that reduced corn harvests nationwide by almost 40 percent, took special care to sow their 1989 spring crops early in case the drought persisted. Besides adjustments in planting and harvest dates, other important adaptations at the farm level include changes in tiliage practices; crop varieties, species, and rotations; and fertilizer, herbicide, and pesticide applications.
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From page 89... ...
More severe climate change will likely require major adaptations, including expansion of irrigation infrastructure, farm abandonment and rural dislocation, In some regions." A special burden may fall on the half billion poorest and hungriest farmers of the world. Robert Kates, director of the Alan Shawn Feinste~n World Hunger Program at Brown University, notes that they are increasingly finding themselves restricted to ecologically marginal land and water resources as their numbers increase and traditional access to important seasonal uses of land or water are lost to development, dams for electricity production, large farms for export crops, or even wildlife and forest conservation.
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