Environment

Table 5.3. Changes in length of growing period (LGP) (days) (top) and percentage of the basin with positive changes of LGP (bottom).

Period

Table 5.3. Changes in length of growing period (LGP) (days) (top) and percentage of the basin with positive changes of LGP (bottom).

Period

SRES scenario

2010-2039

2070-2099

A2

+6

+29

B2

-3

+ 16

A2

+90%

+66%

B2

+58%

+59%

the main cropland is located. It is especially remarkable under the A2 scenario (dark grey, Fig. 5.5) for the period 2070-2099. However, since agriculture in those areas is highly dependent on irrigation (90% of the cropland is irrigated, while agriculture in total consumes 86% of water resources in the basin), the projected summer water shortages may outweigh the positive effects of LGP changes.

In terms of changes of rangeland productivity, the LGP outputs are less optimistic. Semi-deserts in the downstream part of the Syr Darya Basin (Kazakhstan) and alpine meadows upstream (Kyrgyzstan) are very vulnerable to CC-induced changes. Apart from the LGP, runs under the A2 scenario for the time period 2010-2039, rangelands are expected to suffer overall negative changes for the LGP. Those areas are traditionally used as pastures for semi-nomadic sheep, cattle and horse breeding in Central Asia. Any negative changes in the already low LGP in those rangeland areas would potentially result in a less productive or almost vegetation-free landscape and the reduction of rangeland area in the basin.

Climate variability changes would have mostly negative impacts on food security through increasing the probability of extreme dry years. As shown above, the productivity of ecosystems upstream and downstream may prove rather vulnerable to the extremely dry conditions. The increased risks of spring floods in extremely wet years may have negative impacts on industry and environment due to the risks imposed on dams' safety. The areas in the lower basin, particularly in Ksyl-Orda oblast of Kazakhstan, are potentially prone to the winter-spring flood risks. Of special importance for the environment is the issue of radioactive tailings in Mailu-Suu in Kyrgyzstan. In case of extremely high spring floods, the radioactive pollutants may leak into the streams and contaminate the main flow of the Syr Darya.

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