Climate, Climatic Change, and Water Supply (1977) / Chapter Skim
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1. Water Supply and the Future Climate
1. Water Supply and the Future Climate
Pages 25-33
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From page 25... ...
has said that "there is very important climate change going on right now, and if the trend continues, will affect the whole human occupation of the earth—like a half billion people starving." On the other hand, former U.S. Secretary of Agriculture Earl Butz has been quoted to the effect that such statements are at best without scientific bases and are at worst apocalyptic nonsense.
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From page 26... ...
traceable to some varying physical forcing mechanism, e.g., usually a boundary forcing factor such as a volcanic dust veil? From the above it is clear that in studying climatic change the length of the averaging period and the size of the averaging region are quite important.
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From page 27... ...
Based on both some theoretical considerations and observations, Bryson (1974) argues that if the north polar region cools more than the equatorial region, the Asian and African monsoon belts get compressed, that is, they would move slightly equatorward, and the midlatitude baroclinic zones, the westerly belts, would also move toward the equator.
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From page 28... ...
However, in the present world situation in which people are locked into national boundaries, and there is little global food reserve, such marginal shifts could be serious (see the discussion in Schneider and Mesirow, 19761. Since crops are usually planted based on the pre-existing climatic conditions and their expected continuance, slow and gradual changes can be anticipated before crops are planted, thus perhaps avoiding a crisis.
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From page 29... ...
On short time scales, and maybe even longer ones, there is always the possibility of internally caused climatic changes. The atmosphere could be viewed as a very fast oscillating device connected to the oceans by some spring, with the oceans being an even larger mass connected by a bigger spring to another mass, which are the glaciers.
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From page 30... ...
The problem is that no quantitative theory of climate exists to end the intuitive speculations. CLIMATIC MODELS AS ESTIMATORS OF CLIMATIC CHANGE There is one other important "externality" in the system, and that is people.
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From page 31... ...
For example, the summer rainfall and summer temperature in the five major wheat states in the United States during the 1930's "dust bowl era" were below normal and above normal, respectively, and this combination is bad for crops. One should note that there still is much noise in the system including another drought in the 1950's (coincidentally 20-some years away from the previous one)
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From page 32... ...
DUST BOWL ERA HIGH YIELD ERA 1' ~ k .1 I , I , I r I ~ l T I 1~ r r T I SUMMER RAINFALL . B~ nit n ~~} new , ~d ~ mu ~— ~ Lit L{' SUMMER TEMPERATURE 1 , I , I , I , I , I , I , I 00 1910 1920 1930 1940 1950 1960 1970 YEAR FIGURE 1.10 Seventy-five-year record of summer average temperature and rainfall in the five major wheat-producing states of the United States, compiled by Donald Gilman of the National Weather Service and showing the 10-year drought period (i.e., high temperatures and low rainfall)
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From page 33... ...
Simulation of the atmospheric circulation using the NCAR global circulation model with ice-age boundary conditions,J.
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