18.4 Water Resources
423
billion m
3 due to climate change (Deng and Zhao 2001). In the Wuyuer River Basin
in Heilongjiang Province, based on the average of the CSIRO-MK2 and CCSR/NIES
outputs and four emission scenarios (SRES A1, A2, B1, B2), the runoff depth and
coefficients will significantly increase under all scenarios (Sun et al. 2006). In Jialing
River, based on the unfavorable combination in 2050 and 2100, runoff would reduce
by 23.0%–27.9% in 2050 and 28.2%–35.2% in 2100 (Chen and Clarke 2007).
Based on the CMIP5 model simulation, precipitation will increase significantly
under the RCP2.6, RCP4.5, and RCP8.5 scenarios in the future in Northwest China,
especially under RCP8.5. Water vulnerability will be reduced significantly as precipitation increases. Based on Scenario 2, average precipitation will increase by 26.5%
under the RCP8.5 scenario, and water-saving mechanisms will be enhanced in the
2050 s. The vulnerability of water resources in the Tarim River Basin will be substantially reduced, and water resources in Inner Mongolia, the Qaidam Basin, and the Hexi
Corridor will be reduced to medium or low vulnerability. However, water resources in
the Tuha Basin and north of the Tianshan Mountains will remain severely vulnerable
(Wan et al. 2015).
In the Hai River Basin, it is modeled that annual runoff will decrease under warmer
temperatures from 2021–2050, with slight precipitation increases and a significant
increase in evaporation. There will be more frequent flood years and fewer drought
years. Seasonally, precipitation will decrease during the flood season and increase
during non-flood season, and monthly runoff will decrease to some extent (Ding et al.
2010).
In the Yangtze River Basin, under the rise in atmospheric temperature, future
precipitation variation is more complicated. The basin water resources over the next
100 years, as estimated by predictions from the climate model, will decrease in the
next 40 years and then gradually increase (Zhang 2014).
It should be noted that although many studies have been conducted on the estimation of water resources resulting from climate change, the estimates are mainly
decided by the outputs of GCM models and the selection of scenarios.
18.5 Recommendations
Adaption to uncertainties is a painful issue and becomes even more challenging when
preparing for future uncertainties in the long term. With relation to water resources,
it is not yet clear how many changes result from climate change due to increasing
concentrations of carbon dioxide and how many changes derive from other factors.
All we have projected in the future will be impacted by many factors, including social
and economic developments that are more intense than climate change in the short
term. Therefore, water resources’ adaptation to climate change becomes something to
what will happen and what will not happen, based on current understanding, knowledge, and policies. In China, according to existing water resources strategies and the
estimated results of climate change on water resources, the following measures shall
be prepared.
423
billion m
3 due to climate change (Deng and Zhao 2001). In the Wuyuer River Basin
in Heilongjiang Province, based on the average of the CSIRO-MK2 and CCSR/NIES
outputs and four emission scenarios (SRES A1, A2, B1, B2), the runoff depth and
coefficients will significantly increase under all scenarios (Sun et al. 2006). In Jialing
River, based on the unfavorable combination in 2050 and 2100, runoff would reduce
by 23.0%–27.9% in 2050 and 28.2%–35.2% in 2100 (Chen and Clarke 2007).
Based on the CMIP5 model simulation, precipitation will increase significantly
under the RCP2.6, RCP4.5, and RCP8.5 scenarios in the future in Northwest China,
especially under RCP8.5. Water vulnerability will be reduced significantly as precipitation increases. Based on Scenario 2, average precipitation will increase by 26.5%
under the RCP8.5 scenario, and water-saving mechanisms will be enhanced in the
2050 s. The vulnerability of water resources in the Tarim River Basin will be substantially reduced, and water resources in Inner Mongolia, the Qaidam Basin, and the Hexi
Corridor will be reduced to medium or low vulnerability. However, water resources in
the Tuha Basin and north of the Tianshan Mountains will remain severely vulnerable
(Wan et al. 2015).
In the Hai River Basin, it is modeled that annual runoff will decrease under warmer
temperatures from 2021–2050, with slight precipitation increases and a significant
increase in evaporation. There will be more frequent flood years and fewer drought
years. Seasonally, precipitation will decrease during the flood season and increase
during non-flood season, and monthly runoff will decrease to some extent (Ding et al.
2010).
In the Yangtze River Basin, under the rise in atmospheric temperature, future
precipitation variation is more complicated. The basin water resources over the next
100 years, as estimated by predictions from the climate model, will decrease in the
next 40 years and then gradually increase (Zhang 2014).
It should be noted that although many studies have been conducted on the estimation of water resources resulting from climate change, the estimates are mainly
decided by the outputs of GCM models and the selection of scenarios.
18.5 Recommendations
Adaption to uncertainties is a painful issue and becomes even more challenging when
preparing for future uncertainties in the long term. With relation to water resources,
it is not yet clear how many changes result from climate change due to increasing
concentrations of carbon dioxide and how many changes derive from other factors.
All we have projected in the future will be impacted by many factors, including social
and economic developments that are more intense than climate change in the short
term. Therefore, water resources’ adaptation to climate change becomes something to
what will happen and what will not happen, based on current understanding, knowledge, and policies. In China, according to existing water resources strategies and the
estimated results of climate change on water resources, the following measures shall
be prepared.