1. Extremes events and observed regional (South America) trends: A preliminary review Luis J. Mata 1 M.Rusticucci 2, S.Solman 3 J. B. Valdés 4 1 ZEF, University of Bonn, Germany, l.mata@uni-bonn.de 2 Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, mati@at.fcen.uba.ar 3 CIMA (Centro de Investigaciones del Mar y la Atmosfera) and Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, solman@at1.fcen.uba.ar 4 Dept. of Civil Engineering and SAHRA (Sustainability for Semi-Arid Hydrology and Riparian Areas) Center, The University of Arizona, Tucson, Arizona, jvaldes@u.arizona.edu Contributing author: Olga Penalba, Argentina Zentrum für Entwicklungsforschung [ZEF] ISCC Beijing March 2003

2. Outline and Objectives In addition to changes in the mean values it is very important to examine trends in extreme events in the perspective of more generally quantities such as annual temperature and precipitation. It should be expected that a linear change in the mean and a change in the variability would generate a non-linear increase in the probability of the extremes (validation) Theory and Observations

3. The planet averaged an even 14.0 C between 1961-90. The average temperature in 2001 was 14.43 C the second warmest year on record Global average mean temperature has increased by 0.6± 0.2 ° C since the late 19 th century

4. Temperature and Precipitation - The increased in temperature is associated with an stronger warming in daily minimum temperatures than maximum (Easterling et al., 1997) - Global precipitation has also increased since the late 19 th century (IPCC, 2001). - Given these increases, it is expected that there would also be increases in extreme events (Mearns et al., 1984)

5. Figure 3 Trends on extreme temperatures for the period 1960-2000 in the province of Mendoza, Argentina. Temperature extremes Source: Matilde Rusticucci, 2002, personal communication Numbers of days below freezing have decreased Positive tendency for the numbers of days above 30 °C

6. Heavy Precipitation and Floods An increase in heavy precipitationevents should be a primary sign of the climate change that goes together with an increase in greenhouse gases in the atmosphere. An increse concentration of ggh´s in the atmosphere increase infrared radiation, and this global heating at the surface not only act to increase temperatures but also increases evaporation with enhances the atmospheric moisture content (K. Trenberth, 1999) Heavy precipitation is necesary condition for floods

7. Figure 5. Some global examples of floods occurred during the summer of 2002

8. LocationDuration (days)Affected Region (sq. km) x 10 3 Damages (USD per sq. km) Argentina & Brazil 2142485.714 Brazil Central20,7808.974 Brazil West22,2ni Chile12166,9190 Ecuador5452,93ni Peru11333,2ni Trinidad150, 8803.750 Uruguay30187,5ni Venezuela11224,913,34 Some floods in South America during 2002 Data source: Dartmouth Flood Observatory LJM, 2003

9. Figure 4. Rainfall occurred in Venezuela on December 1999 caused over 30,000 deaths and great economic losses. Heavy Precipitation and floods Annual maxima 951mm in 1954 LJM,2002 Source: MARN,2000 cumulative daily

10. Observations

11. Mean T 0 An increase in mean and variance imply a nonlinear increase in the probability of extremes ± 1 SD LJM,2002 Threshold New Mean Probability of high extremes Probability of low extremes Theory

12. Figure 3. Extreme value distributions of maximum flows on Paraná river at Corrientes (1904-1960 and 1961-1997) Source: Valdés, 2002 personal communication

13. Figure 2. A linear increase in the mean and variability imply a non-linear probability of extremes Source: Mata, Workshop of extreme events, Beijing 2002.

14. Figure 5. Annual precipitation PDF at Corrientes, Argentina Annual rainfall in mm D ensity Mean 1902-1944= 1181.88 mm Mean 1945-1999 =1831.00 mm Source: Olga Penalba, personal comunication 2002 LJM,2003

15. Trends on annual and seasonal (DJF and JJA) rainfall in Corrientes, Argentina

16. International Symposium on Climate Change (ISCC) 31 March to 3 April 2003, Beijing; China Thanks ! Xie xie

17. Figure 1: Combined annual land surface air and sea surface temperature anomalies (°C) 1861 to 2000 relative to 1961 to 1990. Two standard error uncertainties are shown as bars on the annual numbers. Global average mean temperature has increased by 0.6± 0.2 ° C since the last century Source: IPCC 2001

18. Extremes events and observed regional (South America) trends: A preliminary review Luis J. Mata 1 M.Rusticucci 2, S.Solman 3 J. B. Valdés 4 1 Center for Develompment Research, University of Bonn, Germany, l.mata@uni-bonn.de 2 Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, mati@at.fcen.uba.ar 3 CIMA (Centro de Investigaciones del Mar y la Atmosfera) and Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, solman@at1.fcen.uba.ar 4 Dept. of Civil Engineering and SAHRA (Sustainability for Semi-Arid Hydrology and Riparian Areas) Center, The University of Arizona, Tucson, Arizona, jvaldes@u.arizona.edu ZEF

19. LocationDuration (days)Affected Region (sq. km) x 10 3 Damages (USD per sq. km) Argentina & Brazil 2142485.714 Brazil Central20,7808.974 Brazil West22,2ni Chile12166,9190 Ecuador5452,93ni Peru11333,2ni Trinidad150, 8803.750 Uruguay30187,5ni Venezuela11224,913,34 Some floods in South America during 2002 Data source: Dartmouth Flood Observatory LJM, 2003