Impact of climate change on water supplydemand balance

Climate anomaly is an important factor influencing the demand of agricultural and industrial water resource. Taking the Nanjing and Hangzhou city located in eastern China as examples, the demand of production water exhibits a moderate positive correlation with the July temperature. In addition, the irrigation water for agriculture is closely correlated with the precipitation in Jiangsu province (Yuan et al. 2000).

Liu (1997) used the output of GCM model with 2 * CO2 concentration (by 2030) as input of the monthly water balance model and the water resources comprehensive assessment model to investigate the possible changes of annual and monthly runoff, the evaporation, and the difference between supply and demand of water resources in 2030. The results showed that in most of the river basins, the influence of climate change on water supply system was confined to the land-surface runoff and water supply of reservoirs due to the characteristics of water supply and demand in China, while the influence on water demand was confined to the agricultural irrigation water which accounts for most of the water consumption. In order to evaluate the influences of climate change on the supply-demand balance of water resource, six issues were addressed within each river basin: the analysis of the present situation on water supply and demand; the projection of water demand in 2030; projection of the available water supply in 2030; the analysis of water supply and demand in 2030 under the condition without considering climate change (1*CO2); the analysis of water supply and demand in 2030 under the condition with considering climate change (2*CO2); the water surplus or deficiency caused by climate change. The impact of climate change on the water deficit in some basins was shown in Table 11.2.

The results shown that: (1) The water deficit between normal years and extremely water deficient years caused by the increase of population and the development of social economy by 2030 will be 1.5*109 ~ 3.6*109 m3 in Beijing-Tianjin-Tangshan area, 3.6* 109 ~ 16.0* 109 m3 in the Huaihe River basin, 16.4* 109 ~ 27.2* 109 m3 in the Yellow River basin, while the Dongjiang River basin will not lack water; (2) The water deficit caused by the increase of population and the development of social economy under four GCM 2*CO2 scenarios by 2030 will be 1.4*109 ~ 5.0*109 m3 in Bei-jing-Tianjin-Tangshan, 2.840* 109 ~ 1.956* 1010 m3 in the Huaihe River, and 6.2* 109 ~ 27.7* 109 m3 in the Yellow River; (3) The water deficit caused by the climate change by 2030 will be -0.2* 109 ~ 1.4* 109 m3 in Beijing-Tianjin-Tangshan area, -0.4* 109 ~ 3.5*109 m3 in the Huaihe River basin, and -0.2*109 ~ 12.1 *109 m3 in the Yellow River basin, however, the water deficit will not be obvious in the Dongjiang River basin; (4) The water deficit caused by climate change will be less than that caused by the increase of population and the development of social economy. But in semi-arid years and extra-dry years, the water deficit would be more severe than normal year in the Beijing-Tianjin-Tangshan area, the Yellow River basin, and the Huaihe River basin, which will induce serious problems of social economy.

Table 11.2 Impact of climate change on water deficit (in 109 m3) in some basins

The re-

Probabil-

Current

Water deficit

Increased water deficit

searched

ity of

water

2XCÜ2

(2XCÜ2 - 1XCÜ2)

region

water

deficit

GISS LLNL UKM

ÜSU GISS LLNL UKM ÜSU

supply

1XCÜ2

ÜH

ÜH

(%)

Beijing-

50

1.5

2.1

2.6

1.3

0.5

1.1

-0.2

Tianjin-

75

3.0

3.9

4.3

3.0

0.9

1.3

0.0

Tangshan

95

3.6

4.6

5.1

3.8

1.0

1.4

0.2

the Huaihe

50

3.6

3.7

4.2

2.8

3.5

0.1

0.6

0.2

-0.1

River

75

5.1

5.3

6.3

5.5

5.0

0.2

1.7

0.4

-0.1

95

15.9

16.5

19.5

17.1

15.5

0.6

3.5

1.2

-0.4

the

50

16.3

16.2

23.8

22.0

19.7

-0.2

7.5

5.7

3.4

Yellow

75

21.8

24.2

31.3

29.6

27.5

2.4

9.4

7.8

5.7

River

95

27.1

33.1

39.3

27.8

36.1

5.9

12.1

10.7

8.9

the Dong-

50

0.7

0.2

0.2

-1.2

jiang

75

0.7

0.2

14.9

-0.1

River

95

1.1

0. 3

0. 3

-1.9

0 0

Post a comment