The Regional Impacts of Climate Change

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Power-related industries could be affected both negatively and positively by climate change. As a result of climate change, demand for electricity for cooling purposes will rise in the summer. In Japan, this demand could rise by 5% by 2050, with a 10% increase in peak demand.

The rate of methane production in biogas generators increases at high temperatures and may be interrupted by low temperatures in the winter, when heating of the digesters is required. Therefore, in north China, for example, global warming may lengthen the periods of high yields and extend the areas in which biogas can be produced without heating the digester. Reduction of water resources, however, could jeopardize hydroelectric energy supplies, and existing petroleum production and distribution systems in the tundra zone could be disrupted because of thawing of permafrost (IPCC 1996, WG II, Chapter 11).

With climate warming, a longer shipping season-with significant cost savings in ice-breaking operations-is likely for rivers in northern Temperate Asia. The Arctic coast would have major periods during which coastal waters were open and navigable. On the other hand, thawing induced by climate warming could result in serious disruptions and increased maintenance costs for railways and highways through the permafrost zone from ground subsidence, side-slope slumpings, landslides, icings, and ice-mound growth. China, for example, has more than 3,000 km of railways and more than 13,000 km of highways in the permafrost zone that would be affected (IPCC 1996, WG II, Sections 7.5.1 and 11.5).

10.2.6. Human Health Heat Stress

An increase in the frequency or severity of heat waves would cause an increase in (predominantly cardiorespiratory) illness and mortality. Although this increase in heat-related deaths would be partially offset by a reduction in cold-related deaths, there are insufficient data to quantify this trade-off. In addition, this balance would vary by location and according to adaptive responses (IPCC 1996, WG II, Chapter 18 Executive Summary).

Based on data collected for persons in Shanghai aged over 65 years for the period 1980-1989, the threshold temperature for heat-related mortality in summer is 34�C. Days with high afternoon temperatures, low wind speeds, and high humidity were associated with the greatest mortality increase. The transient models (GFDL-X2, UKMO-X6) estimate that, for the year 2050, heat-related deaths in Shanghai would increase to 3.6-7.1 times the present figure. Since the warming would be a gradual process, however, this increase could drop to 2.5-2.6 times the present figure if acclimatization of the population is taken into consideration. Climate change also may lead to more frequent occasions with both very hot weather and very high levels of air pollution. The interactive effects of both stresses on human health are not yet well understood (McMichael et al., 1996). Infectious Diseases

Net climate change-related increases in the geographic distribution (elevation and latitude) of vector organisms of infectious diseases (e.g., malarial mosquitoes, schistosome-spreading snails) and changes in the life-cycle dynamics of vector and infective parasites would, in aggregate, increase the potential transmission of many vector-borne diseases in Temperate Asia. Increases in potential transmission areas for malaria, for example, are projected to occur in temperate regions. However, actual climate-related increases in malaria incidence would occur primarily in tropical, subtropical, and less well protected temperate-zone populations that currently are at the margins of endemically infected areas. Some localized decreases also may occur (IPCC 1996, WG II, Chapter 18 Executive Summary).

Increases in non-vector-borne infectious diseases-such as cholera, salmonellosis, and other food- and water-related infections-also could occur as a result of climatic impacts on water distribution, temperature, and microorganism proliferation (IPCC 1996, WG II, Chapter 18 Executive Summary). Recent evidence suggests that the "El Tor" biotype cholera may be classified as a water-based disease. It has spread as far northward as the Korean peninsula. Its mechanism of transmission is still subject to debate, however (McMichael et al., 1996).

Disease surveillance could be strengthened and integrated with other environmental monitoring activities to develop early warning systems; early, environmentally sound public health interventions; and anticipatory social policies to reduce the risk of outbreaks and the subsequent spread of epidemics (IPCC 1996, WG II, Section 12.5.6).

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