11. 50-Years of Climate Extreme Indices Trends and Inventory of Natural Disasters in Chilean Cities (1965–2015)

This chapter reports trends in climate extreme indices (CEI) and comfort indices for the period 1965–2015 and its relationship to historical disasters associated with hydrometeorological events for several Chilean cities. CEI analysis focused on differences in temperature trends and precipitation indices proposed by an Expert Team on Climate Change Detection, Monitoring, and Indices using RClimdex software. The disaster database had been obtained from journals, documents, and the DesInventar platform for 50 years. The results indicate that the minimum temperature increased in most parts of the country and frost events (TNn, CSDI3, and FD0) are decreasing. The heat extremes (TXx, SU30, and SU35) are decreasing in cities located in northern Chile, but increasing in central and southern Chile. The heatwaves (WSDI3 and HWN) have shown a decreasing trend in northern cities located near the coastline and an increasing trend in the rest of the cities, especially those located more centrally and in an inland position, such as Santiago and Chillán. Precipitation (RX3day, RX5day, R20mm, R50mm, and R95p) has decreased, but is more concentrated; and precipitation total (PRCTOT) and the consecutive number of dry days (CDD) are increasing according to the latitudinal gradient of cities. Furthermore, in the last 50 years, urban cities have been affected by approximately 682 natural disasters. The greatest amount of natural disasters occurred during 1991 and 1997, mainly because of precipitation. Both the extreme events and the high frequency of natural disasters show trends toward climate change, but these trends are strongly influenced by natural climate variability and events such as El Niño–La Niña.