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Naota Hanasaki   Dr.   
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Naota Hanasaki published an article in November 2018.
Top co-authors See all
Shinichiro Fujimori

77 shared publications

Department of Environmental EngineeringKyoto University Kyoto Japan

Tomohiro Okadera

17 shared publications

Center for Regional Environmental Research, National Institute for Environmental Studies, 305-8506 Tsukuba, Japan

Taikan Oki

12 shared publications

Institute of Industrial Science, The University of Tokyo, Tokyo, Japan

Norihiro Itsubo

7 shared publications

Faculty of Environmental and Information Studies, Tokyo City University, Yokohama, Japan

Shinjiro Kanae

4 shared publications

Department of Civil and Environmental Engineering, School of Environment and Society, Tokyo Institute of Technology, 2-12-1-M1-6 Ookayama, Meguro-ku, Tokyo 152-8552, Japan

Publication Record
Distribution of Articles published per year 
(2010 - 2018)
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Article 1 Read 0 Citations Limited Role of Working Time Shift in Offsetting the Increasing Occupational‐Health Cost of Heat Exposure Jun’Ya Takakura, Shinichiro Fujimori, Kiyoshi Takahashi, Tom... Published: 21 November 2018
Earth's Future, doi: 10.1029/2018ef000883
DOI See at publisher website ABS Show/hide abstract
Climate change increases workers’ exposure to heat stress. To prevent heat‐related illnesses, according to occupational‐health recommendations, labor capacity must be reduced. However, this preventive measure is expected to be costly, and the costs are likely to rise as the scale and scope of climate change impacts increase over time. Shifting the start of the working day to earlier in the morning could be an effective adaptation measure for avoiding the impacts of labor capacity reduction. However, the plausibility and efficacy of such an intervention have never been quantitatively assessed. Here we investigate whether working time shifts can offset the economic impacts of labor capacity reduction due to climate change. Incorporating a temporally (one‐hour) and spatially (0.5°×0.5°) high‐resolution heat exposure index into an integrated assessment model, we calculated the working time shift necessary to offset labor capacity reduction and economic loss under hypothetical with‐ and without‐realistic‐adaptation scenarios. The results of a normative scenario analysis indicated that a global average shift of 5.7 (4.0‐6.1) hours is required, assuming extreme climate conditions in the 2090s. Although a realistic (< three hours) shift nearly halves the economic cost, a substantial cost corresponding to 1.6% (1.0‐2.4%) of global total gross domestic product is expected to remain. In contrast, if stringent climate‐change mitigation is achieved, a realistic shift limits the remaining cost to 0.14% (0.12‐0.47%) of global total gross domestic product. Although shifting working time is shown to be effective as an adaptation measure, climate‐change mitigation remains indispensable to minimize the impact.
Article 0 Reads 0 Citations Broad threat to humanity from cumulative climate hazards intensified by greenhouse gas emissions Camilo Mora, Daniele Spirandelli, Erik C. Franklin, John Lyn... Published: 19 November 2018
Nature Climate Change, doi: 10.1038/s41558-018-0315-6
DOI See at publisher website
Article 0 Reads 0 Citations A Quantitative Investigation of the Thresholds for Two Conventional Water Scarcity Indicators Using a State-of-the-Art G... Naota Hanasaki, Sayaka Yoshikawa, Yadu Pokhrel, Shinjiro Kan... Published: 25 October 2018
Water Resources Research, doi: 10.1029/2018wr022931
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Among the published global water resource assessments, regions where annual total water withdrawal exceeds 20% and 40% of the availability, or where per capita water availability falls below 1,700 and 500 m3·person−1·year−1, are categorized as being moderately and highly water stressed, respectively, but the rationale for using these thresholds has not been fully explained. Here we show that these thresholds represent the sufficiency of local and renewable water resources, which are estimated daily by a state‐of‐the‐art global hydrological model. We found that water abstraction from local and renewable sources is insufficient (i.e., more than 1% of the annual total water requirement becomes unmet) in a majority of grid cells where annual total water withdrawal exceeds 20% of the availability and/or per capita water availability falls below 1,700 person−1·year−1 (moderate stress). In grid cells where the corresponding values are 40% and/or below 500 m3·person−1·year−1 (high water stress), more than 20% and 60% of the annual total water requirement must be supplied by nonlocal and nonrenewable sources, respectively. These results indicate that conventional indicators and thresholds can be used as a surrogate for measuring daily variations in the sufficiency of local and renewable water sources at the global scale. At the same time, the substitutability of the water withdrawal to availability (WTA) and the water availability per capita (APC) varies by region, which can be primarily attributed to the intensity of the seasonal variation in river flow and irrigated area per capita, respectively. Based on the analyses, new sets of thresholds for WTA and APC are proposed.
Article 0 Reads 0 Citations Economic Consequences of Cooling Water Insufficiency in the Thermal Power Sector under Climate Change Scenarios Qian Zhou, Naota Hanasaki, Shinichiro Fujimori Published: 09 October 2018
Energies, doi: 10.3390/en11102686
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Currently, thermal power is the largest source of power in the world. Although the impacts of climate change on cooling water sufficiency in thermal power plants have been extensively assessed globally and regionally, their economic consequences have seldom been evaluated. In this study, the Asia-Pacific Integrated Model Computable General Equilibrium model (AIM/CGE) was used to evaluate the economic consequences of projected future cooling water insufficiency on a global basis, which was simulated using the H08 global hydrological model. This approach enabled us to investigate how the physical impacts of climate change on thermal power generation influence economic activities in regions and industrial sectors. To account for the uncertainty of climate change projections, five global climate models and two representative concentration pathways (RCPs 2.6 and 8.5) were used. The ensemble-mean results showed that the global gross domestic product (GDP) loss in 2070–2095 due to cooling water insufficiency in the thermal power sector was −0.21% (−0.12%) in RCP8.5 (RCP2.6). Among the five regions, the largest GDP loss of −0.57% (−0.27%) was observed in the Middle East and Africa. Medium-scale losses of −0.18% (−0.12%) and −0.14% (−0.12%) were found in OECD90 (the member countries of the Organization for Economic Co-operation and Development as of 1990) and Eastern Europe and the Former Soviet Union, respectively. The smallest losses of −0.05% (−0.06%) and −0.09% (−0.08%) were found in Latin America and Asia, respectively. The economic impact of cooling water insufficiency was non-negligible and should be considered as one of the threats induced by climate change.
Article 2 Reads 1 Citation Cooling Water Sufficiency in a Warming World: Projection Using an Integrated Assessment Model and a Global Hydrological ... Qian Zhou, Naota Hanasaki, Shinichiro Fujimori, Sayaka Yoshi... Published: 30 June 2018
Water, doi: 10.3390/w10070872
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Thermoelectric power plants in inland regions use primarily riverine water for cooling. The future availability of riverine water will be affected by climatic change. Power generation is expected to grow throughout the 21st century, accompanied by growth in cooling water demand. We estimated cooling water sufficiency globally under the Shared Socioeconomic Pathway 2 scenario with and without climate mitigation throughout the 21st century (2006–2099) at a spatial resolution of 0.5° × 0.5°. We used the Asia-Pacific Integrated Model Computable General Equilibrium Model (AIM/CGE) to project future thermoelectric cooling-water requirements in 17 global regions with no hydrological constraint on water availability, and the H08 global hydrological model to assess whether consumptive water requirements could be met under particular spatiotemporal and hydrological constraints. The results show that cooling water sufficiency will decrease by 7.9% and 11.4% in 2040–2069 (11.3% and 18.6% in 2070–2099) with and without climate mitigation, respectively. A distinct difference was found between with and without climate mitigation in the Middle East and Africa. The predicted insufficiency was attributable primarily to changes in river flow regimes, particularly a general decrease in low flow levels, and to increased water requirements for thermoelectric power generation and other sectors. The results imply that the growing water demand projected by AIM/CGE will not be fulfilled sustainably in many parts of the world, hence considerable additional efforts of reducing water consumption will be required to secure electric power supply. This confirms the importance of coupling integrated assessment models and global hydrological models for consistent water-energy nexus analyses.
Article 4 Reads 8 Citations A global hydrological simulation to specify the sources of water used by humans Naota Hanasaki, Sayaka Yoshikawa, Yadu Pokhrel, Shinjiro Kan... Published: 29 January 2018
Hydrology and Earth System Sciences, doi: 10.5194/hess-22-789-2018
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Humans abstract water from various sources to sustain their livelihood and society. Some global hydrological models (GHMs) include explicit schemes of human water abstraction, but the representation and performance of these schemes remain limited. We substantially enhanced the water abstraction schemes of the H08 GHM. This enabled us to estimate water abstraction from six major water sources, namely, river flow regulated by global reservoirs (i.e., reservoirs regulating the flow of the world's major rivers), aqueduct water transfer, local reservoirs, seawater desalination, renewable groundwater, and nonrenewable groundwater. In its standard setup, the model covers the whole globe at a spatial resolution of 0.5° × 0.5°, and the calculation interval is 1 day. All the interactions were simulated in a single computer program, and all water fluxes and storage were strictly traceable at any place and time during the simulation period. A global hydrological simulation was conducted to validate the performance of the model for the period of 1979–2013 (land use was fixed for the year 2000). The simulated water fluxes for water abstraction were validated against those reported in earlier publications and showed a reasonable agreement at the global and country level. The simulated monthly river discharge and terrestrial water storage (TWS) for six of the world's most significantly human-affected river basins were compared with gauge observations and the data derived from the Gravity Recovery and Climate Experiment (GRACE) satellite mission. It is found that the simulation including the newly added schemes outperformed the simulation without human activities. The simulated results indicated that, in 2000, of the 3628±75km3 yr−1 global freshwater requirement, 2839±50km3 yr−1 was taken from surface water and 789±30km3 yr−1 from groundwater. Streamflow, aqueduct water transfer, local reservoirs, and seawater desalination accounted for 1786±23, 199±10, 106±5, and 1.8±0km3 yr−1 of the surface water, respectively. The remaining 747±45km3 yr−1 freshwater requirement was unmet, or surface water was not available when and where it was needed in our simulation. Renewable and nonrenewable groundwater accounted for 607±11 and 182±26km3 yr−1 of the groundwater total, respectively. Each source differed in its renewability, economic costs for development, and environmental consequences of usage. The model is useful for performing global water resource assessments by considering the aspects of sustainability, economy, and environment.