Info

+1 to +3

STD= standard deviation, DJF= December/January/February, JJA= June/July/August.

STD= standard deviation, DJF= December/January/February, JJA= June/July/August.

The glacier-retreat trend reported in the TAR has intensified, reaching critical conditions in Bolivia, Peru, Colombia and Ecuador (Table 13.3). Recent studies indicate that most of the South American glaciers from Colombia to Chile and Argentina (up to 25°S) are drastically reducing their volume at an accelerated rate (Mark and Seltzer, 2003; Leiva, 2006). Changes in temperature and humidity are the primary cause of the observed glacier retreat during the second half of the 20th century in the tropical Andes (Vuille et al., 2003). During the next 15 years, inter-tropical glaciers are very likely to disappear, affecting water availability and hydropower generation (Ramirez et al., 2001).

Table 13.3. Glacier retreat trends.

Glaciers/Period

Changes/Impacts

Perua,b Last 35 years

22% reduction in glacier total area; reduction of 12% in freshwater in the coastal zone (where 60% of the country's population live). Estimated water loss almost 7,000 Mm3

Peruc

Last 30 years

Reduction up to 80% of glacier surface from small ranges; loss of 188 Mm3 in water reserves during the last 50 years.

Colombiad 1990-2000

82% reduction in glaciers, showing a linear withdrawal of the ice of 10-15 m/yr; under the current climate trends, Colombia's glaciers will disappear completely within the next 100 years.

Ecuador8 1956-1998

There has been a gradual decline glacier length; reduction of water supply for irrigation, clean water supply for the city of Quito, and hydropower generation for the cities of La Paz and Lima.

Bolivia'

Since mid-1990s

Chacaltaya glacier has lost half of its surface and two-thirds of its volume and could disappear by 2010. Total loss of tourism and skiing.

Bolivia' Since 1991

Zongo glacier has lost 9.4% of its surface area and could disappear by 2045-2050; serious problems in agriculture, sustainability of 'bofedales'1 and impacts in terms of socio-economics for the rural populations.

Bolivia' Since 1940

Charquini glacier has lost 47.4% of its surface area.

aVasquez, 2004; bMark and Seltzer, 2003; cNC-Peru, 2001; dNC-Colombia, 2001; eNC-Ecuador, 2000; fFrancou et al., 2003.

aVasquez, 2004; bMark and Seltzer, 2003; cNC-Peru, 2001; dNC-Colombia, 2001; eNC-Ecuador, 2000; fFrancou et al., 2003.

1 Bofedales: wetlands and humid areas of the Andean high plateaux.

13.2.4.2 Environmental trends

Deforestation and changes in land use

In 1990, the total forest area in Latin America was 1,011 Mha, which has reduced by 46.7 Mha in the 10 years from 1990 to 2000 (UNEP, 2003a) (Figure 13.2). In Amazonia, the total area of forest lost rose by 17.2 Mha from 41.5 Mha in 1990 to 58.7 Mha in 2000 (Kaimowitz et al., 2004). The expansion of the agricultural frontier and livestock, selective logging, financing of large-scale projects such as the construction of dams for energy generation, illegal crops, the construction of roads and increased links to commercial markets have been the main causes of deforestation (FAO, 2001a; Laurance et al., 2001; Geist and Lambin, 2002; Asner et al., 2005; FAO, 2005; Colombia Trade News, 2006).

Deforestation in Latin America between 1990-2000

Bolivia Colombia Venezuela Peru Brazil Paraguay Argentina Mexico Ecuador

0 0

Post a comment