Agriculture Reference
In-Depth Information
and winter is shorter; this affects river regimes, natural hazards, water sup-
plies, and people's livelihoods and infrastructure. The extent and health
of high altitude wetlands, green water flows from terrestrial ecosystems,
reservoirs, and water flow and sediment transport along rivers and in lakes
are also affected.
FIGURE 19.1
Dependence of warming on elevation on the Tibetan Plateau (New et al.,
2002).
19.9.2 PRECIPITATION TRENDS
Long-term paleo-climatic studies (e.g., ice core studies on the Tibetan Pla-
teau) show that both wet and dry periods have occurred in the last millen-
nium (Tan et al., 2008, Yao et al., 2008). During the last few decades, inter
seasonal, inter annual, and spatial variability in rainfall trends have been
observed across Asia. In the Himalayan region, both increasing and decreas-
ing trends have been detected. Increasing trends are found on the Tibetan
Plateau in the north-east region (Zhao et al., 2004) and eastern and central
parts (Xu et al., 2007), while the western Tibetan region exhibits a decreas-
ing trend; northern Pakistan also has an increasing trend (Farooq and Khan,
2004). Nepal showed no long-term trend in precipitation between 1948 and
1994 (Shrestha, 2004; Shrestha et al., 2000). A decrease in monsoon precipi-
tation by up to 20% is projected by the end of the century in most parts of
