Impacts of extreme and persistent temperatures : Cold waves and heat waves

ABSTRACT

The most extensive source of data on natural disasters is held by the insurance industry where the most important occurrences around the World are registered according to the number of deaths and the economic and insured damages incurred. Munich Reinsurance (or "Munich Re"), the world's biggest reinsurance company, has documented the 1963 largest natural disasters that have occurred since 1960 in their "MRNatCatSERVICE (1999a). Natural disaster are considered "large" when they considerably exceed self-help capabilities in the region concerned, making supra-regional on international help necessary. This is usually the case when the numbers of deaths are in the thousands and the number of homeless are counted in the hundreds of thousands, or when substantial economic damage is caused. Forty five of these disasters were associated with earthquakes and 5 with volcanic eruption i.e. about a third were not weather - related (see Figure 1). Only 1.2 percent of the 163 disasters were caused by extreme heat and 10.4 percent by extreme cold, making them very rare occurrences among the great catastrophes (for the 113 disasters caused by meteorological conditions, the corresponding percentages are 1.8 percent and 15.0 percent). Winter damage is not caused by low temperatures, but rather by freezing rain, heavy snowfall and high wind speeds that occur in such climatic conditions. the insurance industry classifies disaster caused by atmospheric conditions as the result of "storm", "flooding" and others, a classification system that is, at times, ambiguous. It is unclear, for example, whether flooding in Bangladesh, is caused by a typhoon, counts as a "storm" or "flooding". Equally, the data rarely indicate "cold" or "storm" as the cause of damage where ice storms or blizzards are concerned. Similar ambiguity also arises with drought and heat. According to insurance industry definitions, the issues addressed in this paper fall into the category classified as "others" (see Figure 2). The occurrences identified in this paper are based on reviews of various information sources such as Climatic Perspectives, Transactions of the American Geophysical Union, Frankfurter Allgemeine Zeitung, Lloyd's List, Neue Züricher Zeitung, Monthly Weather Report, Property Claim Services, Online - Reuters, dpa, Süuddeutsche Zeitung, Weekly Climate Bulletin, World Insurance Report, and others, supplied by the MRNatCatSERVICE of Munich Reinsurance (1999a-d). Only confirmed, cross - checked (usually) reports on the extent of damage, obtained from a reliable source, are accepted. For example, the plausibility of damage estimate is checked by the projection of total damage form the insured losses and the insurance density. Sporadic worldwide information on drought/heat is available from 1910 onwards and more or less regularly since 1979. Reports on damage due to winter conditions begin in 1958, and have been available on a regular basis since 1971. Complete information is available since 1986. (AU)