For its work the Adaptation Panel took the available indices of climate change and estimated as best it could the impacts and adaptations to it. An equally logical procedure is to first consider the sensitivities to climate that will cause impacts and evoke adaptations, as has been done in this part, and then, with the sensitivities in mind, ask what indices of climate are relevant.
The investigation of impacts and adaptations produced the following strategic indices of climate change for agencies to monitor and scientists to predict.
The direction and rate of change of:
• First, the flow of water in streams and its supply in soils of a region, including its season and variation from year to year.
• Second, changes in sea level and height of waves on a shore.
• Third, any major shifts in ocean currents.
• Fourth, the timing of seasonal events like blooms and migrations.
• Fifth, untoward extremes of heat and cold.
The argument for the strategic nature of the indices is as follows. Climate is made of many elements, from the sunlight and the pressure of the air to wind and rain. Its effect is in the place where a beach home stands or a corn plant grows. Its effect is at the time of a hurricane or a drought. Thus, a single element like temperature or an average, as over the globe and seasons, will not suffice to estimate impact or adaptation to climate change.
The art of strategy, however, requires selecting a few indices that are most important for estimating the impact. Otherwise, the monitor and predictor of climate are overwhelmed by the demands, and the person studying their result is tangled in a thicket of data. As others have written, ''Policy
actions either to deal with their effects or to prevent changes require concise information about the nature and timing of the effects at local, regional, and global levels" (Chen and Parry, 1987). The strategic few indices most important for figuring the impacts of climate change have not, however, been chosen, either for agencies to monitor or for scientists to predict. An analysis of likely effects of climate change suggests several indices about which detailed and long-term information would be especially useful.
The preeminent outdoor business, exposed to climate, is farming. Although frost kills many crops, species from sugarcane in the south to rape-seed in the north all grow food despite the range of temperatures. But they all need water, and they consume it in proportion to their growth (de Wit, 1958). Calculations show that warming would be hard on a crop grown on the northern margin of the Canadian Prairies unless it were balanced by more precipitation (Stewart, 1981). A steady water supply is the critical element for farming. The bare Mojave Desert and dripping Hoh River valley within one nation with an average precipitation of 750 mm (U.S. Geological Survey, 1984) make the point that global, even national, averages over large areas matter little. The water in a specific place matters.
The migration of Americans within the United States since 1960 shows they do not fear warmer climate (National Research Council, 1983). But they need water wherever they go, and their consumption of water in the Southwest now exceeds the average renewable supply (Gleick, 1990). Where the average supply matches demand, storage smooths the variation. The need for storage, however, depends on the variation across years and seasons (Rogers and Fiering, 1990). So, both average and steadiness of the supply of water are crucial for cities and suburbs as well as for farming.
Flow in streams integrates the effects of weather and landscape. The sensitivity of fish to stream flow is evident. Because different vegetation types are associated with particular seasonal patterns of stream flows, changes in flows signal impending vegetation changes. For example, deciduous forests thrive where soils are sufficiently wetted in the winter that trees can tap deep water and grow when the upper soil layers dry out in summer. Reduction in winter precipitation or reduced flows in summer would signal difficulties for that vegetation.
The sensitivity of industry to climate is exemplified by the generation of electricity. The use of water per unit of production by other industries has steadily declined (David, 1984). Water power obviously needs water, and thermoelectric plants are cooled by water, economically (Miller, 1990). So industry is affected by water supply.
Industry and docks in ports, coastal cities, and even sea resorts share sensitivity to sea level. Their sensitivity to waves is obvious. In addition, the shipping in their ports and estuaries and even water supply drawn just upstream are sensitive to the balance between sea level and stream flow (Schwarz and Dillard, 1990).
Choosing currents like the Gulf Stream and oceanic phenomena like the El Niño-Southern Oscillation for indices carries us from climate elements directly affecting humanity and nature to phenomena affected by climate. Nevertheless, their impacts on nations, farm belts, and coasts is profound, as the difference between 51° North in Labrador and England demonstrates. These currents must be named as strategic indices.
Another strategic index of climate change is phenological phenomena, for example, the date that a particular plant species flowers or a particular species of bird migrates to or from a place. Beauty accounts in part for annual celebrations such as the cherry blossom festival at the Tidal Basin in Washington, D.C. The dates that plants flower and seeds ripen, however, are the footings of farming and civilization. This final index is, of course, a biological response to weather. So, a shift in the dates of phenology indicates the kind of farming and natural vegetation that can prosper in a region.1
Heat and cold waves affect farming, industry, and health. Heat waves have a special impact on the generation of electricity for air conditioning. Winter cold also affects its generation because electricity is used for some heating. It is summer heat waves in several regions, however, that set upper limits on demand on the generators within transmitting distance (Linderer, 1988). Frost kills crops. So the extremes of temperature are crucial.
Lengthening this list would be easy, but it would defeat our goal: a short, strategic list of indices. The five indices listed above are the strategic ones for agencies to monitor and scientists to predict so that the impacts of climate change can be assessed and adaptations can be made.
Although these indices are crucial for estimating impacts and adaptations, they cannot now be computed responsibly. When the menu was
presented to the Effects Panel, the members promptly and correctly insisted that there does not exist, nor is it likely that there will soon exist, a predictive capability that could quantify these indices in a useful or credible way. So, we shall not soon have the scenarios required for estimating impacts and adaptations quantitatively. For a long time we must be satisfied with the sort of examples and benchmarks described in this report.
1. An agriculturalist book of China written by Fan Sheng-Chih in the first century B.C. begins, "The basic principles of farming are: choose the right time, break up the soil, see to its fertility and moisture, hoe early and harvest early" (translated by Shui Sheng-Han, 1982, Science Press, Peking, China).
Chen, R. S., and M. L. Parry. 1987. Policy-Oriented Impact Assessment of Climatic Variation. Report RR-87-7. Laxenburg, Austria: International Institute for Applied Systems Analysis.
David, E. L. 1984. A quarter century of industrial water use and a decade of discharge controls. Water Research Bulletin 20:409–416.
de Wit, C. T. 1958. Transpiration and crop yields. Verslagen lanbouwkundige Onderzoekingen (Agricultural Research Reports) 64.6. Wageningen, The Netherlands: Pudoc.
Gleick, P. H. 1990. Vulnerability of water systems. In Climate Change and U.S. Water Resources, P. E. Waggoner, ed. New York: John Wiley & Sons.
Linderer, R. P. 1988. Regional and national effects of climate change on demands for electricity. In Second North American Conference on Preparing for Climate Change. Washington, D.C.: The Climate Institute.
Miller, K. A. 1990. Water, electricity, and institutional innovation. In Climate Change and U.S. Water Resources, P. E. Waggoner, ed. New York: John Wiley & Sons.
National Research Council. 1983. Changing Climate. Washington, D.C.: National Academy Press.
Rogers, P. P., and M. B. Fiering. 1990. From flow to storage. In Climate Change and U.S. Water Resources, P. E. Waggoner, ed. New York: John Wiley & Sons.
Schwarz, H. E., and L. A. Dillard. 1990. Urban water. In Climate Change and U.S. Water Resources, P. E. Waggoner, ed. New York: John Wiley & Sons.
Stewart, R. B. 1981. Modeling methodology for assessing crop production potentials in Canada. Technical Bulletin 96. Ottawa: Research Branch, Agriculture Canada.
U.S. Geological Survey (USGS). 1984. National water summary 1983Hydrologic events and issues. USGS Water Supply Paper 2250. Washington, D.C.: U.S. Geological Survey.