Climate Change Impacts

Central and South America

Assessment of Projected Climate Change

According to the 2007 IPCC fourth assessment report all of Central and South American will likely warmed in the century.  It was predicted that precipitation would decrease in most of Central America where dry springs would be dryer. Precipitation  was predicted to increase in Tieera del Fuego during the winter and in the south-eastern South American during the summer.  (1)

 

IPPC report stated the it was uncertain how annual and seasonal mean rainfall would change over northern South America, including the Amazon forest. In some regions, there is qualitative consistency among the simulations (rainfall increasing in Ecuador and northern Peru, and decreasing at the northern tip of the continent and in southern northeast Brazil). (1)

 

Key Processes

The IPCC report states that the monsoon system is strongly influenced by El Niño/Southern Oscillation, ENSO and will induce complementary changes in the region.

Warm seasonal precipitation along with the South American Monsoon System dominated the mean seasonal cycle od precipitation in tropical and subtropical latitudes over South America. (1) 

 

The Mediterranean climate of much of Chile makes it sensitive to drying as a consequence of poleward expansion of the South Pacific subtropical high, in close analogy to other regions downstream of oceanic subtropical highs in the Southern Hemisphere (SH). South-eastern South America would experience an increase in precipitation from the same poleward storm track displacement. (1)

 

Temperature

The warming as simulated by the MMD-A1B projections increases approximately linearly with time during this century, but the magnitude of the change and the inter-model range are greater over CAM and AMZ than over SSA (See Figure 1) The annual mean warming under the A1B scenario between 1980 to 1999 and 2080 to 2099 varies in the CAM region from 1.8°C to 5.0°C, with half of the models within 2.6°C to 3.6°C and a median of 3.2°C. The corresponding numbers for AMZ are 1.8°C to 5.1°C, 2.6°C to 3.7°C and 3.3°C, and those for SSA 1.7°C to 3.9°C, 2.3°C to 3.1°C and 2.5°C (2)

 

 

Figure 1
 

Temperature anomalies with respect to 1901 to 1950 for three Central and South American land regions for 1906 to 2005 (black line) and as simulated (red envelope) by MMD models incorporating known forcings; and as projected for 2001 to 2100 by MMD models for the A1B scenario (orange envelope). The bars at the end of the orange envelope represent the range of projected changes for 2091 to 2100 for the B1 scenario (blue), the A1B scenario (orange) and the A2 scenario (red). The black line is dashed where observations are present for less than 50% of the area in the decade concerned. More details on the construction of these figures are given in Figure 3 (3)

 

 

The simulated warming is generally largest in the most continental regions, such as inner Amazonia and northern Mexico (See Figures 2) Seasonal variation in the regional area mean warming is relatively modest, except in CAM where there is a difference of 1°C in median values between DJF and MAM  (2)

Figure 2



 

Temperature and precipitation changes over Central and South America from the MMD-A1B simulations. Top row: Annual mean, DJF and JJA temperature change between 1980 to 1999 and 2080 to 2099, averaged over 21 models. Middle row: same as top, but for fractional change in precipitation. Bottom row: number of models out of 21 that project increases in precipitation. (4)

  

 Central and South America

Figure 3

 

IPCC 2007 Report’s Working Group II:  Impacts, Adaptation, and Vulnerability

Latin America

 

By mid-century, increases in temperature and associated decreases in soil water are projected to lead to gradual replacement of tropical forest by savanna in eastern Amazonia. Semi-arid vegetation will tend to be replaced by arid-land vegetation. There is a risk of significant biodiversity loss through species extinction in many areas of tropical Latin America. (5) 

In drier areas, climate change is expected to lead to salinisation and desertification of agricultural land. Productivity of some important crops is projected to decrease and livestock productivity to decline, with adverse consequences for food security. In temperate zones soybean yields are projected to increase.(5) 

Sea-level rise is projected to cause increased risk of flooding in low-lying areas. Increases in sea surface temperature due to climate change are projected to have adverse effects on Mesoamerican coral reefs, and cause shifts in the location of south-east Pacific fish stocks. (5) 

 

Executive Summary

Latin America

 



 

Highly unusual extreme weather events were reported, such as intense Venezuelan rainfall (1999, 2005), flooding in the Argentinean Pampas (2000-2002), Amazon drought (2005), hail storms in Bolivia (2002) and the Great Buenos Aires area (2006), the unprecedented Hurricane Catarina in the South Atlantic (2004) and the record hurricane season of 2005 in the Caribbean Basin (6)

 

Increases in rainfall in south-east Brazil, Paraguay, Uruguay, the Argentinean Pampas and some parts of Bolivia have had impacts on land use and crop yields, and have increased flood frequency and intensity. On the other hand, a declining trend in precipitation has been observed in southern Chile, south-west Argentina, southern Peru and western Central America. Increases in temperature of approximately 1°C in Mesoamerica and South America, and of 0.5°C in Brazil, were observed. As a consequence of temperature increases, the trend in glacier retreat reported in the Third Assessment Report is accelerating (very high confidence). This issue is critical in Bolivia, Peru, Colombia and Ecuador, where water availability has already been compromised either for consumption or for hydropower generation (6)

 

By the 2020s, the net increase in the number of people experiencing water stress due to climate change is likely to be between 7 and 77 million (medium confidence).

While, for the second half of the century, the potential water availability reduction and the increasing demand from an increasing regional population would increase these figures to between 60 and 150 million. (6)

 

Two extremely intense episodes of the El Niño phenomenon (1982/83 and 1997/98) and other severe climate extremes (EPA, 2001; Vincent et al., 2005; Haylock et al., 2006) have happened during this period, contributing greatly to the heightened vulnerability of human systems to natural disasters (floods, droughts, landslides, etc.). (7) Several components have added to the climate change including natural ecosystems, agriculture, water resources and human health.

 

I found the most interesting threat to Peru is the cereal crops and the lack of especially showing by 2020 but could reach 30% by 2080 under the warmer sceneriao causing many additional people at risk for hunger.  According to Warren hunger risk are likely to reach 5, 26 and 85 million in 2020, 2050 and 2080, respectively.  

 

 

 

"In many crops, rising carbon dioxide leads to increased plant growth," added Field via email. "Models that simulate increasing growth in the future typically include a positive effect of CO2 that is larger than the negative effect of warming, at least for warming of 2 degrees or less."  (8)

 

Credits:

 

(1) http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch11s11-6.html

(2) http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch11s11-6-3.html

(3) http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-11-14.html

(4) http://www.ipcc.ch/publications_and_data/ar4/wg1/en/figure-11-15.html

(5) http://www.ipcc.ch/publications_and_data/ar4/wg2/en/spmsspm-c-11-latin-america.html

(6) http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch13s13-es.html

(7) http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch13s13-2-2.html

(8) http://news.mongabay.com/2007/0316-rice.html#ugxyLTDJ7lhOBcHQ.99