Global Water Availability, Distribution and Use

2017 ◽  
pp. 3-11 ◽  
Author(s):  
Anja du Plessis
Keyword(s):  
Water Availability ◽  
Global Water

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.

Water Resources Management for Sustainable Development

2019 ◽  
pp. 235-250
Author(s):  
Md. Mahfuzar Rahman Chowdhury
Keyword(s):  
Decision Making ◽  
Sustainable Development ◽  
Water Resources ◽  
Water Availability ◽  
Necessary Condition ◽  
Renewable Natural Resources ◽  
Growth Production ◽  
Adequate Quantity ◽  
National Governments ◽  
Global Water

Global water consumption has increased dramatically with the pace of population growth. Production of food and better standard of living for individuals and nations increase the demand of water. Availability of water in adequate quantity and quality is a necessary condition for sustainable development. Knowledge and understanding of freshwater resources is essential for sustainable development too as it ensures management of renewable natural resources for growth and prosperity. Progress towards sustainable development requires engaging a broad range of actors in government, civil society, and business to assure that water is taken into account in their decision-making process and to promote cooperation across disciplines, sectors, and borders. Water resources, if managed properly, can be realized for sharing of greater benefits to the society. National governments have responsibilities towards their citizens, and therefore, the national governments and the global community need to take action and track progress over a much broader set of water-related challenges.

scholarly journals Global water availability under high-end climate change: A vulnerability based assessment

2019 ◽  
Vol 175 ◽  
pp. 52-63 ◽  
Author(s):  
A.G. Koutroulis ◽  
L.V. Papadimitriou ◽  
M.G. Grillakis ◽  
I.K. Tsanis ◽  
R. Warren ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Availability ◽  
Global Water

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 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.

Global water dynamics: issues for the 21st century

2002 ◽  
Vol 45 (8) ◽  
pp. 53-64 ◽  
Author(s):  
Slobodan P. Simonovic
Keyword(s):  
Water Balance ◽  
System Dynamics ◽  
Water Use ◽  
Water Availability ◽  
Global Scale ◽  
Water Dynamics ◽  
Novel Approach ◽  
Collapse Behavior ◽  
Global World ◽  
Global Water

The WorldWater system dynamics model has been developed for modeling the global world water balance and capturing the dynamic character of the main variables affecting water availability and use in the future. Despite not being a novel approach, system dynamics offers a new way of addressing complex systems. WorldWater simulations are clearly demonstrating the strong feedback relation between water availability and different aspects of world development. Results of numerous simulations are contradictory to the assumption made by many global modelers that water is not an issue on the global scale. Two major observations can be made from early simulations: (a) the use of clean water for dilution and transport of wastewater, if not dealt with in other ways, imposes a major stress on the global world water balance; and (b) water use by different sectors is demonstrating quite different dynamics than predicted by classical forecasting tools and other water-models. Inherent linkages between water quantity and quality sectors with food, industry, persistent pollution, technology, and non-renewable resources sectors of the model create shoot and collapse behavior in water use dynamics. This paper discusses a number of different water-related scenarios and their implications on the global water balance. In particular, two extreme scenarios (business as usual – named “Chaos”, and unlimited desalination – named “Ocean”) are presented in the paper. Based on the conclusions derived from these two extreme cases a set of more moderate and realistic scenarios (named “Conservation”) is proposed and their consequences on the global water balance are evaluated.

scholarly journals Climate change will affect global water availability through compounding changes in seasonal precipitation and evaporation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Goutam Konapala ◽  
Ashok K. Mishra ◽  
Yoshihide Wada ◽  
Michael E. Mann
Keyword(s):  
Climate Change ◽  
Water Availability ◽  
Seasonal Precipitation ◽  
Global Water
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