Research Theme

Research Theme

Area Theme 1
Predictive understanding of Earth system changes based on physical evidence
Atmosphere and Ocean Research Institute, The University of Tokyo
Area Representative
Masahiro Watanabe
Professor, Atmosphere and Ocean Research Institute, The University of Tokyo
Area subjects
  • Advanced studies for global climate simulations
  • Attributing and Predicting Earth System Variability
Participating organizations
  • JAMSTEC, National Institute for Environmental Studies, Japan Meteorological Business Support Center
Area Theme 2
Biogeochemical modeling and climate simulations for carbon budget assessment
Japan Agency for Marine-Earth Science and Technology(JAMSTEC)
Area Representative
Michio Kawamiya
Director, Japan Agency for Marine-Earth Science and Technology(JAMSTEC)
Area subjects
  • A hierarchical approach to advancing Earth system modeling
  • Development of an integrated framework for Earth system research
  • Earth-human system interaction and future scenario analysis
  • Technical and clerical support for inter-theme cooperation
Participating organizations
  • National Institute for Environmental Studies, Central Research Institute of Electric Power Industry
Area Theme 3
Increasing the sophistication of climate change projections around Japan
Japan Meteorological Business Support Center(JMBSC)
Area Representative
Hiroyuki Tsujino
Principal Investigator, Japan Meteorological Business Support Center
Area subjects
  • Development of projection system and analysis of mechanism for climate change around Japan
  • Creating climate change projection information and elucidating extreme event mechanisms for promoting regional and basin scale adaptation measures
  • Creation of high-accuracy climate projection datasets for vulnerable regions in the world

Promotion of projection
  • products use and user communication
Participating organizations
  • Hokkaido University, Tohoku University, JAMSTEC, Nagoya University
Area Theme 4
Development of an integrated hazard projection model
Disaster Prevention Research Institute, Kyoto University
Area Representative
Nobuhito Mori
Professor, Disaster Prevention Research Institute, Kyoto University
Area subjects
  • Integrated hazard modelling and nationwide future projections
  • Elaborate hazard model development and hazard mechanism elucidation
  • Quantification of climate change factors in extreme hazards
  • International cooperation for hazard and risk assessments in the Asia-Pacific region
  • Flexible adaptation strategies to the future changes in hazard and society
Participating organizations
  • Hokkaido University, Public Works Research Institute ICHARM, National Agriculture and Food Research Organization

Area Theme 1

Area Theme 1
Predictive understanding of Earth system changes based on physical evidence

Predictive understanding of Earth system changes based on physical evidence

Area Representative:
Masahiro Watanabe(Professor, Atmosphere and Ocean Research Institute (AORI), The University of Tokyo)
領域代表者 渡部 雅浩(東京大学大気海洋研究所 教授)

The Sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC), issued in August 2021, concluded that human influence has unequivocally warmed the climate system. Global surface temperature has risen by 1.1°C since the preindustrial era, and is likely contributing to global increases in the frequency and intensity of extreme weather. In many developed countries, including Japan, both climate change adaptation and mitigation measures have been put in place. Mitigation is necessary to achieve carbon neutrality and the target of the Paris Agreement to limit global warming to below 1.5 or 2°C.
All climate change policies and actions are ideally based on scientific knowledge and evidence. Robust explanations of the cause of observed warming and future climate projections consistent with our understanding of past climate changes provide the basis for policies and actions. They can be obtained from climate simulations using physically-based global climate models (GCMs). Over the past 20 years, our group has led the climate modeling efforts in the MEXT research program. We developed an in-house GCM, MIROC, and have used it to simulate climate change on the Earth Simulator, generating large amounts of data publicly available. On the basis of these data, our group has also published a number of world-class research papers and contributed to the past three IPCC assessment cycles. In Research Area 1 of the SENTAN program, we intend to upgrade MIROC by using satellite products for validation. We plan to contribute to the IPCC Seventh Assessment Report (AR7) and advance our understanding of the causes of Earth system changes, particularly those aspects that were associated with low confidence levels in AR6. We will produce a database of near-term climate and greenhouse gas prediction based on an initialization technique implemented to MIROC. Our research will further improve our understanding of the mechanisms of large-scale climate change and variability, attributions of observed changes, constraints on future projections, and estimates of human influence on individual extreme weather events, also known as event attribution.

Subject Representative
(ⅰ) Advanced studies for global climate simulations
a Advancing prediction systems for near-term climate-carbon cycle changes Hiroaki Tatebe
Group Leader, Japan Agency for Marine-Earth Science and Technology
b Understanding physical processes of climate change with a synergistic use of global models and satellite observations Kentaroh Suzuki
Professor, Atmosphere and Ocean Research Institute, The University of Tokyo
c Understanding and prediction of terrestrial environmental changes Kei Yoshimura
Professor, Institute of Industrial Science, The University of Tokyo
(ⅱ) Attributing and Predicting Earth System Variability
a Understanding global warming levels and reducing uncertainty in climate projections Tomoo Ogura
Head, National Institute for Environmental Studies
b Mechanism understanding of past climate changes and future projections Yu Kosaka
Associate Professor, Research Center for Advanced Science and Technology, The University of Tokyo
c Deepening and advancement of event attribution studies Yukiko Imada
Investigator, Japan Meteorological Business Support Center
図1
Climate phenomena examined in Research Area 1 are indicated by the black symbols and the expected outcomes (data and knowledge) are indicated in red. Research Area 1 focuses on climate change on global and large scales, and produces data that will be downscaled to create regional climate projections in Research Area 3. We will generate near-term Earth system predictions in collaboration with Research Area 2. We aim to produce actionable climate science and provide evidence-based climate change information for decision makers and the general public to support their decisions and changes in relation to climate change.

Area Theme 2

Area Theme 2
Biogeochemical modeling and climate simulations for carbon budget assessment

Global model of ecosystems and human activity—Supporting decision-making with respect to climate change measures

Area Representative:
Michio Kawamiya(Director, Japan Agency for Marine-Earth Science and Technology (JAMSTEC))
領域代表者 河宮 未知生(海洋研究開発機構 気候モデル高度化研究プロジェクトチーム プロジェクト長)

The carbon budget refers to the maximum amount of CO2 emissions that can be allowed under a certain global warming target. Earth System Models (ESMs), which include essential elements of the global carbon cycle such as forests and marine ecosystems, are used to evaluate this indicator critical for estimating the necessary CO2 emission reductions. The IPCC Sixth Assessment Report (AR6), published in 2021, estimated that the remaining carbon budget for limiting global warming to below 1.5 °C is about 400–650 GtCO2 (33%– 67% likelihood). The quantification of the carbon budget has substantial consequences for the society but has very large uncertainty. Therefore, it is necessary to narrow the uncertainty as much as possible by increasing ESM sophistication and understanding the sources of uncertainty; nitrogen and nutrient cycles, for example, need to be incorporated into the conventional carbon cycle to improve our understanding of the dynamics of all the major greenhouse gases. Furthermore, hydroxyl (OH) radicals play a critical role in determining the lifetime of greenhouse gases such as methane but their past and future changes under the influence of anthropogenic pollutants remain a subject of debate. To advance our understanding of the interactions between society and climate change, we will quantify the carbon budget and explore corresponding emission reduction pathways using a model suite that combines an ESM with a socioeconomic model. We will also focus on outreach, and our research findings can be used as a scientific basis for planning and decision-making, including supporting international negotiations on emission reductions and the Global Stocktake.

Subject Representative
(ⅰ)A hierarchical approach to advancing Earth system modeling
a Advancing biogeochemical process in Earth system models Tomohiro Hajima
Deputy Group Leader, Japan Agency for Marine-Earth Science and Technology
b Integrating multiple evidence with climate model emulators Junichi Tsutsui
Associate Vice President, Central Research Institute of Electric Power Industry
(ⅱ)Development of an integrated framework for Earth system research Hiroaki Tatebe
Group Leader, Japan Agency for Marine-Earth Science and Technology
(ⅲ)Earth-human system interaction and future scenario analysis
a Feedback analysis of Earth-human systems Kaoru Tachiiri
Group Leader, Japan Agency for Marine-Earth Science and Technology
b Scenario analysis of Earth-human systems Tokuta Yokohata
Chief Senior Researcher, National Institute for Environmental Studies
(ⅳ)Technical and clerical support for inter-theme cooperation Michio Kawamiya
Director, Japan Agency for Marine-Earth Science and Technology
図1
Various processes will be integrated into the Earth System Model (ESM). Research findings will be synthesized to provide the society with a scientific basis for decision-making with respect to future pathways. We will increase model sophistication, e.g., by incorporating methane release from permafrost, and introduce novel elements, including detailed atmospheric chemistry processes and forest fires and combining the ESM with a human activity model. We will also focus on outreach to contribute to decision-making with respect to climate change measures.

Area Theme 3

Area Theme 3
Increasing the sophistication of climate change projections around Japan

Actionable climate science—Promoting research for a national climate change scenario

Area Representative:
Hiroyuki Tsujino(Japan Meteorological Business Support Center (JMBSC))
Hiroyuki Tsujino

The World Climate Research Program (WCRP) strongly advocates actionable climate science, which connects research results with society. In Japan, the national Climate Change Projection Dataset forms the basis for climate change measures; updates will be made on a relatively regular basis starting 2022 and there are demands for different types of data (see figure). In Research Area 3, we aim to create regional climate projections with increased accuracy and diversity and reduced uncertainty to support local government decision-making. Data application will be expanded to include the fields of hydrology and water resources, and our results can be used for the management of water use, fisheries, aquaculture, and flood control. We will develop a model system that includes sophisticated regional climate models, global models with ocean effects, and enhanced ocean information around Japan. In addition, we will focus on regional climate, extreme events, and data application across different domains of the society through the following activities.

(1) To stimulate the application of research results across the society, we will produce information that meets users’ needs by increasing model sophistication, generating marine data, and improving reproducibility in the modeling of extreme phenomena and our understanding of climate mechanisms.

(2) To further facilitate the use of research results, we will engage in two-way communication with users and establish a user-friendly information provision system in cooperation with various domestic organizations, including DIAS, which is responsible for the system.

(3) To contribute to the development and implementation of climate change adaptation measures in vulnerable regions overseas that are similar to Japan and are facing increasing risks of heavy rains, floods, and storm surges, we will create highly accurate climate forecast datasets for these regions in collaboration with researchers in the regions.


*Area Representative
until 2024 March : Izuru Takayabu (JMBSC)
since 2024 April : Hiroyuki Tsujino (JMBSC)

Subject Representative
(ⅰ)Development of projection system and analysis of mechanism for climate change around Japan Hiroyuki Tsujino
Principal Investigator, Japan Meteorological Business Support Center
a Development of projection system for high-resolution global climate change Ryo Mizuta
Investigator, Japan Meteorological Business Support Center
b Development of projection system for regional climate and land surface in Japan Hiroaki Kawase
Investigator, Japan Meteorological Business Support Center
c Development of projection system for ocean change around Japan Hideyuki Nakano
Investigator, Japan Meteorological Business Support Center
Yoichi Ishikawa
Director, Japan Agency for Marine-Earth Science and Technology
d Analysis of mechanism for climate change around Japan Hirokazu Endo
Investigator, Japan Meteorological Business Support Center
(ⅱ)Creating climate change projection information and elucidating extreme event mechanisms for promoting regional and basin scale adaptation measures Tomohito Yamada
Professor, Faculty of Engineering, Hokkaido University
a Developing high-resolution data sets and prediction method using dynamical and statistical methods Tomohito Yamada
Professor, Faculty of Engineering, Hokkaido University
Kazuhisa Tsuboki
Professor, Nagoya University
b Analysis of climate and weather factors causing recent extreme weather events Hiroaki Kawase
Investigator, Japan Meteorological Business Support Center
c Elucidating the mechanism of extreme events considering the risk increase and maximum magnitude at the regional and basin scale Takeshi Yamazaki
Professor, Graduate School of Science, Tohoku University
(ⅲ)Creation of high-accuracy climate projection datasets for vulnerable regions in the world Akihiko Murata
Investigator, Japan Meteorological Business Support Center
Promotion of projection products use and user communication Toshiyuki Nakaegawa
Investigator, Japan Meteorological Business Support Center
図1
The components of Research Area 3 are enclosed in the red box. Green drops indicate the various sectors that are users of the national scenario.

Area Theme 4

Area Theme 4
Development of an integrated hazard projection model

Advancing/Integrating weather-related disaster and water resources modeling and projecting future extremes for climate disaster risk information

Area Representative:
Nobuhito Mori(Professor, Disaster Prevention Research Institute, Kyoto University)
領域代表者 中北 英一(京都大学防災研究所 教授)

Research Area 4 focuses on Climatic Impact Drivers (CIDs) following the IPCC Sixth Assessment Report (AR6). Research Area 4 connects WGI (The Physical Science Basis) and WGII (Impacts, Adaptation, and Vulnerability) of the IPCC. We will advance and integrate process models of weather-related hazards, water resources, and major ecosystems targeting the CIDs and produce future projections. Using advanced sub-models, we will integrate hazard models of weather-related hazards and water resources over a wide range of spatial and temporal scales. The compound hazards will be considered based on the integration of hazard models. Furthermore, we will consider extreme risks, including changes in exposure and vulnerability with changes in hazards and water resources. Such a risk assessment will lead to connection to adaptations.
Coordinated future projections of weather-related hazards, water resources, and ecosystems will be generated from the climate projection datasets of Research Areas 1–3. The projection will be analyzed to identify the impacts of future extreme weather events on extreme hazards, water resources, and ecosystems targeting the CIDs in Japan and Southeast Asia. We will analyze hazard changes in response to rising temperatures. We will conduct event attribution and pseudo-global warming studies to estimate and quantify the contribution of warming to hazard projections from past, present, and future extreme weather events. Additionally, we will develop a framework for adaptation policies based on climate disaster prevention information. Impact assessments will be expanded and incorporated into exposure assessments and form the basis of our contribution to the IPCC AR7.
More than 100 researchers from four major institutions and 43 partner institutions, including universities and national research institutes, will work together to conduct research in this area.

Subject Representative
(ⅰ)Integrated hazard modelling and nationwide future projections Takahiro Sayama
Professor, Disaster Prevention Research Institute, Kyoto University
(ⅱ)Elaborate hazard model development and hazard mechanism elucidation Kenji Tanaka
Professor, Disaster Prevention Research Institute, Kyoto University
a Hazard assessments of wind hazard, water-related disasters and water resources Kenji Tanaka
Professor, Disaster Prevention Research Institute, Kyoto University
b Hazard assessments of forests and coastal ecosystems Masahiko Fujii
Associate Professor, Faculty of Environmental Earth Science, Hokkaido University
(ⅲ)Quantification of climate change factors in extreme hazards Tetsuya Takemi
Professor, Disaster Prevention Research Institute, Kyoto University
(ⅳ)Professor, Disaster Prevention Research Institute, Kyoto University Yasuto Tachikawa
Professor, Graduate School of Engineering, Kyoto University
(ⅴ)Flexible adaptation strategies to the future changes in hazard and society Toshio Fujimi
Associate Professor, Disaster Prevention Research Institute, Kyoto University
図1
Sub-themes 4-i to 4-iii include model development and future projections; sub-theme 4-iv focuses on future projections and their social implementation in Southeast Asia; sub-theme 4-v focuses on the development of adaptation models. Our data and results will be published in research papers and will also be available to support the implementation of domestic and international policies.