scholarly journals A global water scarcity assessment under shared socio-economic pathways – Part 1: Water use

2012 ◽  
Vol 9 (12) ◽  
pp. 13879-13932 ◽  
Author(s):  
N. Hanasaki ◽  
S. Fujimori ◽  
T. Yamamoto ◽  
S. Yoshikawa ◽  
Y. Masaki ◽  
...  
Keyword(s):  
Water Use ◽  
21St Century ◽  
Water Scarcity ◽  
Climate Modeling ◽  
Water Withdrawal ◽  
Industrial Water ◽  
Domestic Water ◽  
Irrigation Area ◽  
Five Factors ◽  
Global Water

Abstract. A novel global water scarcity assessment for the 21st century is presented in a two-part paper. In this first paper, water use scenarios are presented for the latest global hydrological models. The scenarios are compatible with the socio-economic scenarios of the Shared Socio-economic Pathways (SSPs), which are a part of the latest set of scenarios on global change developed by the integrated assessment, IAV (climate change impact, adaptation, and vulnerability assessment), and climate modeling community. The SSPs depict five global situations based on substantially different socio-economic conditions during the 21st century. Water use scenarios were developed to reflect the key concepts underpinning each situation. Each scenario consists of five factors: irrigation area, crop intensity, irrigation efficiency, industrial water withdrawal, and municipal water withdrawal. The first three factors are used to estimate agricultural water withdrawal. All factors were developed using simple models based on a literature review and analysis of historical records. The factors are grid-based at a spatial resolution of 0.5° × 0.5° and cover the whole 21st century at 5-yr intervals. Each factor displays a wide variation among the different global situations depicted: the irrigation area in 2085 varies between 270 and 450 km2, industrial water between 246 and 1714 km3 yr−1, and domestic water withdrawal between 573 and 1280 km3 yr−1. The water use scenarios can be used for global water scarcity assessments by identifying the regions vulnerable to water scarcity and analyzing the timing and magnitude of scarcity conditions.

scholarly journals A global water scarcity assessment under Shared Socio-economic Pathways – Part 1: Water use

2013 ◽  
Vol 17 (7) ◽  
pp. 2375-2391 ◽  
Author(s):  
N. Hanasaki ◽  
S. Fujimori ◽  
T. Yamamoto ◽  
S. Yoshikawa ◽  
Y. Masaki ◽  
...  
Keyword(s):  
Water Use ◽  
21St Century ◽  
Water Scarcity ◽  
Water Demand ◽  
Climate Modeling ◽  
Electricity Production ◽  
Irrigation Water Demand ◽  
Irrigated Area ◽  
Municipal Water ◽  
Global Water

Abstract. A novel global water scarcity assessment for the 21st century is presented in a two-part paper. In this first paper, water use scenarios are presented for the latest global hydrological models. The scenarios are compatible with the socio-economic scenarios of the Shared Socio-economic Pathways (SSPs), which are a part of the latest set of scenarios on global change developed by the integrated assessment, the IAV (climate change impact, adaptation, and vulnerability assessment), and the climate modeling community. The SSPs depict five global situations based on substantially different socio-economic conditions during the 21st century. Water use scenarios were developed to reflect not only quantitative socio-economic factors, such as population and electricity production, but also key qualitative concepts such as the degree of technological change and overall environmental consciousness. Each scenario consists of five factors: irrigated area, crop intensity, irrigation efficiency, and withdrawal-based potential industrial and municipal water demands. The first three factors are used to estimate the potential irrigation water demand. All factors were developed using simple models based on a literature review and analysis of historical records. The factors are grid-based at a spatial resolution of 0.5° × 0.5° and cover the whole 21st century in five-year intervals. Each factor shows wide variation among the different global situations depicted: the irrigated area in 2085 varies between 2.7 × 106 and 4.5 × 106 km2, withdrawal-based potential industrial water demand between 246 and 1714 km3 yr−1, and municipal water between 573 and 1280 km3 yr−1. The water use scenarios can be used for global water scarcity assessments that identify the regions vulnerable to water scarcity and analyze the timing and magnitude of scarcity conditions.

scholarly journals A global water scarcity assessment under shared socio-economic pathways – Part 2: Water availability and scarcity

2012 ◽  
Vol 9 (12) ◽  
pp. 13933-13994 ◽  
Author(s):  
N. Hanasaki ◽  
S. Fujimori ◽  
T. Yamamoto ◽  
S. Yoshikawa ◽  
Y. Masaki ◽  
...  
Keyword(s):  
Water Use ◽  
Water Availability ◽  
Water Scarcity ◽  
Climate Models ◽  
Water Cycle ◽  
Water Withdrawal ◽  
Electricity Production ◽  
Daily Water ◽  
Consumption Demand ◽  
Global Water

Abstract. A global water scarcity assessment for the 21st century was conducted under the latest socio-economic scenario for global change studies, namely Shared Socio-economic Pathways (SSPs). SSPs depict five global situations with substantially different socio-economic conditions. In the accompanying paper, a water use scenario compatible with the SSPs was developed. This scenario considers not only quantitative socio-economic factors such as population and electricity production but also qualitative ones such as the degree of technological change and overall environmental consciousness. In this paper, water availability and water scarcity were assessed using a global hydrological model called H08. H08 simulates both the natural water cycle and major human activities such as water withdrawal and reservoir operation. It simulates water availability and use at daily time intervals at a spatial resolution of 0.5° × 0.5°. A series of global hydrological simulations were conducted under the SSPs, taking into account different climate policy options and the results of climate models. Water scarcity was assessed using an index termed the Cumulative Withdrawal to Demand ratio, which is expressed as the accumulation of daily water withdrawal from a river over the potential daily water consumption demand. This index can be used to express whether renewable water resources are available from rivers when required. The results suggested that by 2071–2100 the population living under severely water stressed conditions for SSP1-5 will reach 2588–2793 × 106 (39–42% of total population), 3966–4298 × 106 (46–50%), 5334–5643 × 106 (52–55%), 3427–3786 × 106 (40–45%), 3164–3379 × 106 (46–49%), respectively, if climate policies are not adopted. Even in SSP1 (the scenario with least change in water use and climate) global water scarcity increases considerably, as compared to the present day. This is mainly due to the growth in population and economic activity in developing countries, and partly due to hydrological changes induced by global warming.

scholarly journals Reconstruction of global gridded monthly sectoral water withdrawals for 1971–2010 and analysis of their spatiotemporal patterns

2018 ◽  
Vol 22 (4) ◽  
pp. 2117-2133 ◽  
Author(s):  
Zhongwei Huang ◽  
Mohamad Hejazi ◽  
Xinya Li ◽  
Qiuhong Tang ◽  
Chris Vernon ◽  
...  
Keyword(s):  
Water Use ◽  
High Latitude ◽  
Irrigation Water ◽  
Electricity Generation ◽  
The United States ◽  
Water Withdrawal ◽  
Domestic Water ◽  
Summer Peak ◽  
Water Withdrawals ◽  
Global Water

Abstract. Human water withdrawal has increasingly altered the global water cycle in past decades, yet our understanding of its driving forces and patterns is limited. Reported historical estimates of sectoral water withdrawals are often sparse and incomplete, mainly restricted to water withdrawal estimates available at annual and country scales, due to a lack of observations at seasonal and local scales. In this study, through collecting and consolidating various sources of reported data and developing spatial and temporal statistical downscaling algorithms, we reconstruct a global monthly gridded (0.5∘) sectoral water withdrawal dataset for the period 1971–2010, which distinguishes six water use sectors, i.e., irrigation, domestic, electricity generation (cooling of thermal power plants), livestock, mining, and manufacturing. Based on the reconstructed dataset, the spatial and temporal patterns of historical water withdrawal are analyzed. Results show that total global water withdrawal has increased significantly during 1971–2010, mainly driven by the increase in irrigation water withdrawal. Regions with high water withdrawal are those densely populated or with large irrigated cropland production, e.g., the United States (US), eastern China, India, and Europe. Seasonally, irrigation water withdrawal in summer for the major crops contributes a large percentage of total annual irrigation water withdrawal in mid- and high-latitude regions, and the dominant season of irrigation water withdrawal is also different across regions. Domestic water withdrawal is mostly characterized by a summer peak, while water withdrawal for electricity generation has a winter peak in high-latitude regions and a summer peak in low-latitude regions. Despite the overall increasing trend, irrigation in the western US and domestic water withdrawal in western Europe exhibit a decreasing trend. Our results highlight the distinct spatial pattern of human water use by sectors at the seasonal and annual timescales. The reconstructed gridded water withdrawal dataset is open access, and can be used for examining issues related to water withdrawals at fine spatial, temporal, and sectoral scales.

scholarly journals Integrated assessment of global water scarcity over the 21st century under multiple climate change mitigation policies

2014 ◽  
Vol 18 (8) ◽  
pp. 2859-2883 ◽  
Author(s):  
M. I. Hejazi ◽  
J. Edmonds ◽  
L. Clarke ◽  
P. Kyle ◽  
E. Davies ◽  
...  
Keyword(s):  
Climate Change ◽  
21St Century ◽  
Water Availability ◽  
Water Scarcity ◽  
Carbon Tax ◽  
Assessment Model ◽  
Baseline Scenario ◽  
Water Demands ◽  
Global Water ◽  
Mitigation Policies

Abstract. Water scarcity conditions over the 21st century both globally and regionally are assessed in the context of climate change and climate mitigation policies, by estimating both water availability and water demand within the Global Change Assessment Model (GCAM), a leading community-integrated assessment model of energy, agriculture, climate, and water. To quantify changes in future water availability, a new gridded water-balance global hydrologic model – namely, the Global Water Availability Model (GWAM) – is developed and evaluated. Global water demands for six major demand sectors (irrigation, livestock, domestic, electricity generation, primary energy production, and manufacturing) are modeled in GCAM at the regional scale (14 geopolitical regions, 151 sub-regions) and then spatially downscaled to 0.5° × 0.5° resolution to match the scale of GWAM. Using a baseline scenario (i.e., no climate change mitigation policy) with radiative forcing reaching 8.8 W m−2 (equivalent to the SRES A1Fi emission scenario) and three climate policy scenarios with increasing mitigation stringency of 7.7, 5.5, and 4.2 W m−2 (equivalent to the SRES A2, B2, and B1 emission scenarios, respectively), we investigate the effects of emission mitigation policies on water scarcity. Two carbon tax regimes (a universal carbon tax (UCT) which includes land use change emissions, and a fossil fuel and industrial emissions carbon tax (FFICT) which excludes land use change emissions) are analyzed. The baseline scenario results in more than half of the world population living under extreme water scarcity by the end of the 21st century. Additionally, in years 2050 and 2095, 36% (28%) and 44% (39%) of the global population, respectively, is projected to live in grid cells (in basins) that will experience greater water demands than the amount of available water in a year (i.e., the water scarcity index (WSI) > 1.0). When comparing the climate policy scenarios to the baseline scenario while maintaining the same baseline socioeconomic assumptions, water scarcity declines under a UCT mitigation policy but increases with a FFICT mitigation scenario by the year 2095, particularly with more stringent climate mitigation targets. Under the FFICT scenario, water scarcity is projected to increase, driven by higher water demands for bio-energy crops.

scholarly journals The Water Footprint of Kathmandu Metropolitan City

2015 ◽  
Vol 28 ◽  
pp. 73-80
Author(s):  
Mohan Bikram Shrestha ◽  
Udhab Raj Khadka
Keyword(s):  
Water Use ◽  
Water Footprint ◽  
Industrial Water ◽  
Total Water ◽  
Domestic Water ◽  
Rapid Urbanization ◽  
Water Project ◽  
Metropolitan City ◽  
Industrial Water Use ◽  
Per Capita

The water footprint is consumption-based indicator of water use. Water footprint is defined as the total volume of both indirect and the direct freshwater used for producing goods and services consumed by individuals or inhabitants of community. There are many studies regarding the direct water use but studies incorporating both direct and indirect water use is deficient. This study tries to estimate total volume of water based on the consumption pattern of different commodities by individuals of Kathmandu Metropolitan city using extended water footprint calculator. The average water footprint of individuals appears to be 1145.52 m3/yr. The indirect and direct water footprint appears to be 1070.82 Mm3/yr and 46.59 Mm3/yr respectively which cumulatively give the total water footprint of Kathmandu Metropolitan City of 1117.40 Mm3/yr. This volume is equal to 2.27 times the annual flow the River Bagmati. The indirect water footprint includes food water footprint of 1055.60 Mm3/yr or 2.14 times the annual flow and industrial water use of 15.22 Mm3/yr or 0.03 times the annual flow while the direct water footprint includes domestic water use of 46.59 Mm3/yr or 0.09 times the annual flow. In food water footprint, cereals consumption shared the highest contribution of 34.82% followed by meat consumption with share of 32.62% in total water footprint. Per capita per day water use of inhabitants appears to be 3138 liters which includes water use in food items of 2965 liters, industrial water use of 43 liters and domestic water use of 131 liters. The per capita per day domestic water use is 90 liters more than supplement of 41 liters by the water operator of Kathmandu Valley. Per capita per day domestic water use is already 5 liters more than expected improvement in water supplement of 126 liters per capita per day in 2025 after accomplishment of Melamchi water project. And, it is expected to increase further observing the rapid urbanization of Kathmandu Metropolitan City. The study showed water footprint of individuals is directly related to food consumption behavior, life style and services used therefore it is necessary to initiate water offsetting measures at individual level and water operator to find environmentally sustainable alternatives along with ongoing water project to fulfill demand. J. Nat. Hist. Mus. Vol. 28, 2014: 73-80

scholarly journals A global water scarcity assessment under Shared Socio-economic Pathways – Part 2: Water availability and scarcity

2013 ◽  
Vol 17 (7) ◽  
pp. 2393-2413 ◽  
Author(s):  
N. Hanasaki ◽  
S. Fujimori ◽  
T. Yamamoto ◽  
S. Yoshikawa ◽  
Y. Masaki ◽  
...  
Keyword(s):  
Water Use ◽  
Water Availability ◽  
Water Scarcity ◽  
Climate Models ◽  
Water Cycle ◽  
Electricity Production ◽  
Daily Consumption ◽  
Water Abstraction ◽  
Daily Water ◽  
Global Water

Abstract. A global water scarcity assessment for the 21st century was conducted under the latest socio-economic scenario for global change studies, namely Shared Socio-economic Pathways (SSPs). SSPs depict five global situations with substantially different socio-economic conditions. In the accompanying paper, a water use scenario compatible with the SSPs was developed. This scenario considers not only quantitative socio-economic factors such as population and electricity production but also qualitative ones such as the degree of technological change and overall environmental consciousness. In this paper, water availability and water scarcity were assessed using a global hydrological model called H08. H08 simulates both the natural water cycle and major human activities such as water abstraction and reservoir operation. It simulates water availability and use at daily time intervals at a spatial resolution of 0.5° × 0.5°. A series of global hydrological simulations were conducted under the SSPs, taking into account different climate policy options and the results of climate models. Water scarcity was assessed using an index termed the Cumulative Abstraction to Demand ratio, which is expressed as the accumulation of daily water abstraction from a river divided by the daily consumption-based potential water demand. This index can be used to express whether renewable water resources are available from rivers when required. The results suggested that by 2071–2100 the population living under severely water-stressed conditions for SSP1-5 will reach 2588–2793 × 106 (39–42% of total population), 3966–4298 × 106 (46–50%), 5334–5643 × 106 (52–55%), 3427–3786 × 106 (40–45%), 3164–3379 × 106 (46–49%) respectively, if climate policies are not adopted. Even in SSP1 (the scenario with least change in water use and climate) global water scarcity increases considerably, as compared to the present-day. This is mainly due to the growth in population and economic activity in developing countries, and partly due to hydrological changes induced by global warming.

scholarly journals Integrated assessment of global water scarcity over the 21st century – Part 1: Global water supply and demand under extreme radiative forcing

2013 ◽  
Vol 10 (3) ◽  
pp. 3327-3381 ◽  
Author(s):  
M. I. Hejazi ◽  
J. Edmonds ◽  
L. Clarke ◽  
P. Kyle ◽  
E. Davies ◽  
...  
Keyword(s):  
21St Century ◽  
Water Availability ◽  
Water Scarcity ◽  
Water Demand ◽  
Integrated Assessment ◽  
Radiative Forcing ◽  
Assessment Model ◽  
Water Demands ◽  
Global Population ◽  
Global Water

Abstract. Water scarcity conditions over the 21st century both globally and regionally are assessed in the context of climate change, by estimating both water availability and water demand within the Global Change Assessment Model (GCAM), a leading community integrated assessment model of energy, agriculture, climate, and water. To quantify changes in future water availability, a new gridded water-balance global hydrologic model – namely, the Global Water Availability Model (GWAM) – is developed and evaluated. Global water demands for six major demand sectors (irrigation, livestock, domestic, electricity generation, primary energy production, and manufacturing) are modeled in GCAM at the regional scale (14 geopolitical regions, 151 sub-regions) and then spatially downscaled to 0.5° × 0.5° resolution to match the scale of GWAM. Using a baseline scenario (i.e., no climate change mitigation policy) with radiative forcing reaching 8.8 W m−2 (equivalent to the SRES A1Fi emission scenario) and a global population of 14 billion by 2095, global annual water demand grows from about 9–10% of total annual renewable freshwater in 2005 to about 32–37% by 2095. This results in more than half of the world population living under extreme water scarcity by the end of the 21st century. Regionally, the demand for water exceeds the amount of water availability in two GCAM regions, the Middle East and India. Additionally, in years 2050 and 2095 36% (28%) and 44% (39%) of the global population, respectively is projected to live in grid cells (in basins) that will experience greater water demands than the amount of available water in a year (i.e., the water scarcity index (WSI) > 1.0). This study implies an increasingly prominent role for water in future human decisions, and highlights the importance of including water in integrated assessment of global change.

scholarly journals Global modeling of withdrawal, allocation and consumptive use of surface water and groundwater resources

2014 ◽  
Vol 5 (1) ◽  
pp. 15-40 ◽  
Author(s):  
Y. Wada ◽  
D. Wisser ◽  
M. F. P. Bierkens
Keyword(s):  
Surface Water ◽  
Water Use ◽  
Groundwater Resources ◽  
Water Withdrawal ◽  
Groundwater Use ◽  
Consumptive Water Use ◽  
Surface Water And Groundwater ◽  
Terrestrial Water ◽  
Consumptive Water ◽  
Global Water

Abstract. To sustain growing food demand and increasing standard of living, global water withdrawal and consumptive water use have been increasing rapidly. To analyze the human perturbation on water resources consistently over large scales, a number of macro-scale hydrological models (MHMs) have been developed in recent decades. However, few models consider the interaction between terrestrial water fluxes, and human activities and associated water use, and even fewer models distinguish water use from surface water and groundwater resources. Here, we couple a global water demand model with a global hydrological model and dynamically simulate daily water withdrawal and consumptive water use over the period 1979–2010, using two re-analysis products: ERA-Interim and MERRA. We explicitly take into account the mutual feedback between supply and demand, and implement a newly developed water allocation scheme to distinguish surface water and groundwater use. Moreover, we include a new irrigation scheme, which works dynamically with a daily surface and soil water balance, and incorporate the newly available extensive Global Reservoir and Dams data set (GRanD). Simulated surface water and groundwater withdrawals generally show good agreement with reported national and subnational statistics. The results show a consistent increase in both surface water and groundwater use worldwide, with a more rapid increase in groundwater use since the 1990s. Human impacts on terrestrial water storage (TWS) signals are evident, altering the seasonal and interannual variability. This alteration is particularly large over heavily regulated basins such as the Colorado and the Columbia, and over the major irrigated basins such as the Mississippi, the Indus, and the Ganges. Including human water use and associated reservoir operations generally improves the correlation of simulated TWS anomalies with those of the GRACE observations.

scholarly journals An integrated model for the assessment of global water resources – Part 2: Applications and assessments

2008 ◽  
Vol 12 (4) ◽  
pp. 1027-1037 ◽  
Author(s):  
N. Hanasaki ◽  
S. Kanae ◽  
T. Oki ◽  
K. Masuda ◽  
K. Motoya ◽  
...  
Keyword(s):  
Water Resources ◽  
Water Use ◽  
Water Availability ◽  
Asian Monsoon ◽  
Environmental Flow ◽  
Water Withdrawal ◽  
Monsoon Region ◽  
Asian Monsoon Region ◽  
Meteorological Forcing ◽  
Global Water

Abstract. To assess global water resources from the perspective of subannual variation in water availability and water use, an integrated water resources model was developed. In a companion report, we presented the global meteorological forcing input used to drive the model and six modules, namely, the land surface hydrology module, the river routing module, the crop growth module, the reservoir operation module, the environmental flow requirement module, and the anthropogenic withdrawal module. Here, we present the results of the model application and global water resources assessments. First, the timing and volume of simulated agriculture water use were examined because agricultural use composes approximately 85% of total consumptive water withdrawal in the world. The estimated crop calendar showed good agreement with earlier reports for wheat, maize, and rice in major countries of production. In major countries, the error in the planting date was ±1 mo, but there were some exceptional cases. The estimated irrigation water withdrawal also showed fair agreement with country statistics, but tended to be underestimated in countries in the Asian monsoon region. The results indicate the validity of the model and the input meteorological forcing because site-specific parameter tuning was not used in the series of simulations. Finally, global water resources were assessed on a subannual basis using a newly devised index. This index located water-stressed regions that were undetected in earlier studies. These regions, which are indicated by a gap in the subannual distribution of water availability and water use, include the Sahel, the Asian monsoon region, and southern Africa. The simulation results show that the reservoir operations of major reservoirs (>1 km3) and the allocation of environmental flow requirements can alter the population under high water stress by approximately −11% to +5% globally. The integrated model is applicable to assessments of various global environmental projections such as climate change.

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