Using the PRECIS regional climate modeling system, this study analyzes the distribution of
extremes of temperature and precipitation in South America in the recent past (1961-1990)
and in a future (2071-2100) climate under the IPCC SRES A2 and B2 emissions scenarios.
The results show that for the present climate the model simulates well the spatial
distribution of extreme temperature and rainfall events when compared with observations,
with temperature more realistic. The observations over the region are far from
comprehensive which compromises the assessment of model quality. In the future the
occurrence of warm nights is projected to be more frequent in the entire tropical South
America, while the occurrence of cold night events is likely to decrease. Significant
changes in rainfall extremes and dry spells are also projected. These include increased
intensity of extreme precipitation events over most of Southeastern South America and
western Amazonia consistent with projected increasing trends in total rainfall in these
regions. In Northeast Brazil and eastern Amazonia, smaller or no changes are seen in
projected rainfall intensity though significant changes are seen in the frequency of
consecutive dry days. In all the future climate scenarios considered all parts of the region
would experience significant and often different changes in rainfall and temperature
extremes. These changes would have impacts in biodiversity, human health, water
resources and may have to be considered in the implementation of adaptation measures to
cope with climate change.

Last Updated: 2007-12-13