1. Observed climate changes in Southern South America Vicente Barros
San José de Costa Rica
May 27, 2003
LINEAR TENDS
TENDENCIAS ANUALES
1956 – 1991
mm/year

2. Surface temperature trend: Subtropical region

3. Surface temperature trends Resumme:
Subtropical region
Mean temperature: no apreciable changes
Positive trend in minimum temperature
Negative trend in maximum temperature
Patagonia region
Positive trends in mean temmpertaure
Increasing toward the south

5. LINEAR TENDS
TENDENCIAS ANUALES
1956 – 1991
mm/year

6. Mean annual
precipitation

7. Isohiets shift
to the west

8. 30% INCREAMENT !

9. HYDROLOGICAL RESPONSE

10. Mean annual discharge of the Parná River at Corrientes

11. Is the hydrological change a response to climate or to land use change?
If it is response to both:
how much is due to each one?

12. HYDROLOGY: AMPLIFICATION OF THE CLIMATE SIGNAL
Precipitation on the Plata basin (m3 s-1)
Discharge
(m3 s-1)
Evaporaction +
Infiltration (m3 s-1)
1998
107000
36600
70400
1999
81600
20440
61600
Difference
23 %
44 %
13 %
El Niño
76000
25250
50750
La Niña
71000
21640
49360
7 %
17 %
3 %
72000
19300
52700
83500
26000
56500
16 %
35 %
9 %
[1]For lack of available precipitation records north 20E S during the period, rainfall rates over La Plata basin for this and for the period were calculated only for the area south of this latitude.

13. Wavelet Analysis of the mean monthly streamflow of the Paraná River ( ), showing the increament of the components of 4 and 8 years since the 70’s by Angel Menendez

14. Greatest discharges in the ParanáRiver
(Jaime & Menéndez, INA)

15. Greatest ebbs in the Paraná River
(Jaime & Menéndez, INA)

16. The new conditions are more frequently out of the coping range

17. 1997/98 Flood of the Paraná River
(Satellite imagens from CONAE)

18. Rainfall anomalies for April (+) of El Niño events (1950-99)

19. BENEFITS The agriculture frontier shifted westward
Greater productivity in the humid Pampas
More hydropower

20. DAMAGES
Tropical deseases
More frequent floods
Increased litigation

21. Are these changes related to the increased Greenhouse gasses concentrations?

22. (a) (b)

24. CONCLUSIONS
Southeastern South America had an important increase in Precipitation
This change was enhanced in some hydrological systems
It caused important economic benefits and damages
It could be related to GHG human emissions

25. Thank you...