Faculty Profiles - TANIKAWA, Hiroki

The N-terminal disordered regions of LKP2 and ZTL are essential for circadian clock function. Reviewed Open Access

Tanikawa H, Maeda AE, Ono A, Matsuo H, Okada EG, Muranaka T, Kinoshita T, Nakamichi N

Plant & cell physiology Vol. 67 ( 1 ) page： 5 - 7 2026.1

Estimation of Interior Materials and Household Goods Stock in Housing for a Circular Economy Reviewed Open Access

HAYASHI Yuki, HASEGAWA Masatoshi, SHIRAKAWA Hiroaki, TANIKAWA Hiroki

Papers on Environmental Information Science Vol. ceis39 ( 0 ) page： 134 - 139 2025.12

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Center for Environmental Information Science

A comprehensive understanding of the available resources in cities is essential for the successful implementation of a circular economy. In current building stock estimation, “interior materials and household goods” have not been considered yet. Therefore, this study focused on them and created their intensity. The purpose of this study is to clarify the location and quantity of recyclable materials. I estimated the intensity of interior materials and household goods and compared it with the intensity of structural materials from previous studies. As a result, it was estimated that an amount equivalent to about 3%–4% of the structural material in the wooden house by 2×4 construction method is accumulated in a house as interior materials and household goods.

DOI： 10.11492/ceispapers.ceis39.0_134

Mapping nationwide material stock turnover: High-resolution spatial analysis of building material stock and flow patterns across Japan 2003-2020 Reviewed

CiNii Research

Nagata, S; Hasegawa, M; Fishman, T; Shirakawa, H; Tanikawa, H

JOURNAL OF INDUSTRIAL ECOLOGY Vol. 29 ( 6 ) page： 2131 - 2143 2025.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Industrial Ecology

Understanding the dynamics of building material stocks and flows, including the turnover processes of building stock, is important for promoting sustainable resource use in cities. This study provides high-resolution, integrated mapping of building material stocks and flows across various cities and regions in Japan, offering a detailed view of the country's spatial material metabolism. This research combines bottom-up estimates of material stocks and flows with spatial analysis using material metabolism indicators, examining how patterns of material stock turnover vary across Japan. Spatial variations in material stock turnover highlight regional factors that influence stock–flow dynamics and offer insights into local resource use and policy development tailored to specific regional contexts. In this study, the national stock turnover rate in 2020 is estimated to be 1.16%/year for inflow and 0.64%/year for outflow, with more active metabolism observed in the central areas of large metropolitan regions and lower levels in low-density rural areas. Additionally, distinct patterns of material metabolism were observed across districts, associated with redevelopment and urban sprawl. This study illustrates how spatially detailed approaches can support the analysis of stock–flow dynamics across the country and contribute to the development of sustainable resource use strategies tailored to local conditions.

DOI： 10.1111/jiec.70100

Assessing resource efficiency in Vietnam: Insights from material stock and flow indicators Reviewed

Nguyen, TPT; Hasegawa, M; Shirakawa, H; Tanikawa, H

JOURNAL OF INDUSTRIAL ECOLOGY Vol. 29 ( 6 ) page： 2214 - 2233 2025.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Industrial Ecology

This study aims to comprehensively evaluate Vietnam's resource efficiency to support sustainable development by developing and applying an integrated resource efficiency assessment framework (IREAF). Since the 1990s, Vietnam's economy has undergone rapid development, resulting in unprecedented growth in resource consumption and environmental pressures. To address this, we propose a multidimensional framework that combines economy-wide material flow analysis, IPAT-based decomposition, and environmental impact indicators. Using national-scale data from 1990 to 2021, this study shows that domestic material consumption increased by over eight times, with construction materials dominating. Net additions to stock remained high, reflecting large-scale infrastructure expansion. Limited absolute decoupling between economic growth and resource use was shown throughout the period, although material productivity has slightly improved since 2015. Our decomposition analysis highlights affluence per urban resident and urbanization as key drivers of escalating resource inflow, while efficiency gains have sometimes offset these pressures. The IREAF framework enables holistic monitoring of material, energy, and water flows and can guide policy through hotspot identification and efficiency benchmarking. The findings underscore the need for stronger policies on circular economy practices, data collection, and green-growth incentives. For other emerging economies, this study's approach provides a replicable model to enhance sustainable resource management.

DOI： 10.1111/jiec.70101

Development of Time-series Building Basements Data Using Building and Tenant Data Case Study of the 23 Wards of Tokyo Reviewed Open Access

SUGIMOTO Kenji, TANIKAWA Hiroki

ENVIRONMENTAL SCIENCE Vol. 38 ( 5 ) page： 84 - 96 2025.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：SOCIETY OF ENVIRONMENTAL SCIENCE, JAPAN

<p>Although many existing studies focus on material stock and flow in urban buildings, the scale and distribution of building basements have not been fully explored due to the constraints in data compilation. In this study, we created time-series building basement data in the Tokyo 23 wards from 2003 to 2022 using building data and tenant database. Analysis of the spatial distribution and temporal changes in building basements based on this dataset revealed that many buildings with basements were located around major stations such as Tokyo Station. It was shown that the top five (Chiyoda, Minato, Shinjuku, Chuo, and Shibuya) accounted for 60％ of all building basements. Moreover, the area of building basements increased by 40.8％ from 2003 to 2022, indicating that the increase in buildings with large floor areas and multiple basement floors contributed to this expansion. Although the ratio of the basement floor area to the total floor area is a small value of 1.3–1.5％ in the 23 wards, since the basement floor area is as large as about 11.19 million m<sup>2</sup>, the building stock is estimated to be large by including the basement floor.</p>

DOI： 10.11353/sesj.38.84

"Resource-carbon" redistribution caused by Japan's cement production and consumption: a life-cycle based multilayer perspective Reviewed

CiNii Research

Bai, YY; Hasegawa, M; Shirakawa, H; Yamasue, E; Tanikawa, H

ENVIRONMENTAL IMPACT ASSESSMENT REVIEW Vol. 115 2025.8

Language：English Publishing type：Research paper (scientific journal) Publisher：Environmental Impact Assessment Review

Inter-reginal trade of raw materials, energy, and products within Japan's cement supply chain creates substantial telecoupled material and carbon flows. Temporal dynamics in regional cement consumption and supply chain structure have discrepant effects on production regions and resource suppliers. However, existing literature studies primarily focused on single-year carbon flows and obscured transportation impacts. Therefore, this study developed a process-based life cycle multi-layer supply network integrating transport data, trade statistics, and gravity model to quantify material and carbon flows embedded in Japan's prefectural cement supply network from 2010 to 2022. Results reveal that in 2022, up to 88 % of total material requirement (TMR) and 74 % of carbon footprint (CF) impacts attributed to inter-prefectural trade and energy imports, while transportation processes contributed about 5 % to the total impacts. Domestically, TMR and CF transfers primarily flowed from northern regions (Hokkaido, Iwate) and southern regions (Fukuoka, Yamaguchi, Kochi) toward three major economic centers, while smaller transfer networks emerged around Saitama, Niigata, and Mie prefectures. The production-side TMR and CF of major impact-exporting prefectures have recently declined due to reduced remote consumption, while Hyogo demonstrated slight growth driven by supply increases. Internationally, approximately 38 % of TMR impacts were externalized to coal-exporting countries, with Australia and Indonesia replacing Russia's historical dominance following geopolitical changes, leading to a 22 % increase in long-distance maritime impacts. These findings underscore the need for implementing targeted cross-cutting mitigation strategies (i.e., low-carbon fuels and material-efficient design) to achieve a more sustainable and resilient cement industry in Japan.

DOI： 10.1016/j.eiar.2025.108051

How did traffic and climate situations worsen material consumption and waste from road infrastructure in Bangkok? Reviewed

Kronnaphat Khumvongsa, Jing Guo, Suthida Theepharaksapan, Varameth Vichiensan, Masatoshi Hasegawa, Hiroaki Shirakawa, Hiroki Tanikawa

Resources, Conservation and Recycling Vol. 222 2025.8

Shedding light on the shadows Transparency challenge in background life cycle inventory data Reviewed Open Access

Guo, J; Li, RQ; Zhang, RR; Qi, JC; Li, N; Xu, CQ; Chiu, ASF; Wang, YT; Tanikawa, H; Xu, M

JOURNAL OF INDUSTRIAL ECOLOGY Vol. 29 ( 3 ) page： 766 - 776 2025.6

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Industrial Ecology

Life cycle assessment (LCA) hinges on the transparency and reliability of inventory data. However, the transparency of background life cycle inventory (LCI) data sources remains unexamined. This research assesses data transparency in mainstream LCI databases using a two-step examination system based on source findability and accessibility. Six major databases (ecoinvent, GaBi, U.S. Life Cycle Inventory Database, European Life Cycle Database, Inventory Database for Environmental Analysis, and Chinese Life Cycle Database) were analyzed by sampling processes and tracing their sources. The results reveal widespread transparency issues, with only 40%–60% of sampled processes having findable sources and <5% being fully accessible in certain databases. Incomplete documentation and complex cross-referencing between processes and sources posed key barriers. The lack of transparency undermines LCA credibility and necessitates reconstructing databases for enhanced traceability. Although a preliminary study, these findings highlight the challenge of data transparency and provide a methodology to evaluate databases. This drives collective action to uphold transparency standards, restoring trust in LCA as a sustainability decision-making tool.

DOI： 10.1111/jiec.70010

Environmental Impacts of Buildings in Central Business Districts of Metro Manila, Philippines Reviewed Open Access

URMENITA Francis, HASEGAWA Masatoshi, Shirakawa Hiroaki, TANIKAWA Hiroki

Environmental Information Science Vol. 54 ( 1 ) page： 112 2025.4

関与物質総量の観点から見た都市の成長がもたらす環境負荷の評価 Reviewed Open Access

丹羽倫太郎, 長谷川正利, 白川博章, 山末英嗣, 谷川寛樹

環境情報科学 Vol. 54 ( 1 ) page： 115 2025.4

気候変動適応に向けた洪水影響の空間分析 Reviewed Open Access

岡田大翔, 長谷川正利, 白川博章, 谷川寛樹

環境情報科学 Vol. 54 ( 1 ) page： 116 2025.4

住宅の内装材・家財を考慮した資材投入原単位の拡張に関する研究 Reviewed Open Access

林優輝, 長谷川正利, 白川博章, 谷川寛樹

環境情報科学 Vol. 54 ( 1 ) page： 105 2025.4

Land Cover Analysis of Flood Hazard Areas in Metro Manila, Philippines Reviewed Open Access

CAGAMPAN Mark Angelo, HASEGAWA Masatoshi, SHIRAKAWA Hiroaki, TANIKAWA Hiroki

Environmental Information Science Vol. 54 ( 1 ) page： 111 2025.4

Resource Intensity in the Japanese Transportation System: Integration of Vehicle and Infrastructure Reviewed Open Access

Naotaka Haraguchi, Shoki Kosai, Shunsuke Kashiwakura, Eiji Yamasue, Hiroki Tanikawa

Sustainability Vol. 17 ( 6 ) page： 2437 - 2437 2025.3

CO2 uptake estimation in Japan's cement lifecycle Reviewed

Sawa, D; Yamashita, N; Tanikawa, H; Daigo, I; Maruyama, I

JOURNAL OF CLEANER PRODUCTION Vol. 486 2025.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Cleaner Production

Carbon dioxide (CO<inf>2</inf>) uptake by cement-containing products has attracted significant interest as an important source of CO<inf>2</inf> absorption. This study provides an advanced estimation of CO<inf>2</inf> uptake during the cement lifecycle in Japan by incorporating dynamic material stock-flow analysis into the model. Concrete stock-flow and CO<inf>2</inf> uptake from 1870 to 2070 are estimated by reflecting country-specific characteristics such as concrete mix design, surface-to-volume ratio of buildings, presence or absence of coating resins and/or covering materials, and exposure climate. Annual CO<inf>2</inf> uptake in the cement lifecycle was estimated to be 2.6 million tonnes/year in 2020, corresponding to 13.9% of CO<inf>2</inf> emissions from calcination during cement production. Annual CO<inf>2</inf> uptake by in-use concrete accounted for 86.8% of the total in 2020, whereas that by end-of-life concrete was relatively small throughout the estimation period. CO<inf>2</inf> uptake is expected to increase slightly in the late 2020s, then decrease to 2.3 to 2.4 million tonnes/year by 2070. Our results were lowered by comparing those of previous studies, suggesting that the most critical aspect was affected by the local climate. The high-precision analysis highlighted the importance of integrating local climate factors, surface-to-volume ratio of structures based on the domestic design guidelines and examples, and modeling of end-of-life concrete, providing fundamental knowledge for incorporating CO<inf>2</inf> uptake into the carbon-neutral strategy of Japanese cement industry.

DOI： 10.1016/j.jclepro.2024.144542

Material Stock Analysis for Implementing Circular Economic Concepts in Mongolia’s Construction and Transportation Sectors Reviewed Open Access

Tulga Mendjargal, Eseosa Halima Ighile, Tsedevsuren Bat-Ochir, Naho Yamashita, Ganchimeg Jamsran, Hiroaki Shirakawa, Hiroki Tanikawa

Journal of Circular Economy Vol. 3 ( 1 ) 2025

Language：English Publishing type：Research paper (scientific journal) Publisher：DSRPT GbR

This study quantifies the material stock and flow in Mongolia's construction and transportation sectors. In the last few years, a rapid development in Mongolia's construction and transportation industries has led to large amounts of construction waste. Most raw materials extracted are accumulated in building infrastructure and other durable goods. This study used the bottom-up approach to estimate the material stock (MS) of Mongolia's transportation and construction industries. The analysis shows that in 2020, Mongolia accumulated about 180.7 Mt of material stock (MS) with a potential of 26.6 Mt (14.7%) of waste from the transportation and construction sectors in the future. The study also highlights materials' distribution and intensities across each sector and successfully establishes a material stock database for Mongolia's transportation and construction sectors. From the results, it can be deduced that MSFA studies will assist policymakers in forecasting future demand for materials and estimating the environmental impact, which can aid in developing relevant policies on reducing the negative environmental impacts and implementing circular economy concepts.

DOI： 10.55845/YMBG9888

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Strategic Environmental Assessment Indicator System for Spatial Land-Use Plans, Comprehensive Natural Resource and Environmental Management, and Adaptation to Climate Change in Lao PDR and the Regional Context Reviewed Open Access

SOULIVONG Khamphone, SHIRAKAWA Hiroaki, TANIKAWA Hiroki

Environmental Information Science Vol. 2025 ( 1 ) page： 46 - 60 2025

Language：English Publishing type：Research paper (scientific journal) Publisher：Center for Environmental Information Science

Strategic environmental assessment (SEA) is a critical tool for evaluating the potential environmental, social, and economic effects of strategies, policies, plans, and programs (SPPPs), particularly for addressing climate change and fostering sustainable development. By identifying methods to avoid, mitigate, and reduce adverse effects, SEA ensures that development aligns with environmental, social, and economic sustainability goals. A key component is the development of appropriate indicators for measuring the environmental, social, and economic risks associated with the proposed SPPPs. This study aims to create SEA indicators tailored to spatial land-use plans, natural resource management, and climate change adaptation in the Lao PDR, as well as at the regional level. Using a mixed-methods approach, this research employs the Delphi method, expert panels, stakeholder consultations, and document reviews to gather data. As a result, this paper presents a standardized system comprising 57 indicators, categorized into four dimensions: environmental, social, economic, and institutional. These indicators are grounded in the Lao PDR’s environmental policy framework, sustainable development principles, and the UN’s Sustainable Development Goals. This indicator system can not only enhance the effectiveness of SEA in the Lao PDR but also provide a replicable model for regional application, ensuring a balanced approach to development and environmental stewardship.

DOI： 10.11492/ceispapersen.2025.1_46