5:15 PM - 6:45 PM
[ACG46-P01] Interdisciplinary scenario research and the role of emulators
Keywords:Climate model, Earth System model, Impact assessment, Integrated assessment
1. Introduction
Scenarios, as a tool for analyzing uncertain futures, play a central role in assessing long-term climate change itself and climate policies (mitigation and adaptation measures). Climate change scenario research covers a wide range of areas, from greenhouse gas emissions, carbon cycle, climate sensitivity, and regional temperature increases and their climate impacts, and the Intergovernmental Panel on Climate Change (IPCC) research community in several Working Groups (WG1, WG2, and WG3) has collaborated to conduct comprehensive analyses. This paper reviews the cross-disciplinary scenario research initiated by the IPCC's new scenario process from the perspective of international and domestic trends, with a particular focus on emulators and the related concepts (e.g., Global Warming Level). Much of this paper is based on our recent review published elsewhere.
2. current status of scenario research
The IPCC has been using a variety of scenarios, such as SA90, IS92, and SRES (Special Report on Emissions Scenarios) , depending on the time period. Various scenarios have been used depending on the time period. In particular, the SRES scenarios, which appeared in 2000, have played an important role in several IPCC assessment reports. At the same time, however, various problems have been recognized. Various elements of the scenarios are exchanged as input-output data among the research community representing each working group. Therefore, the impact assessment community downstream in the information exchange flow is affected by information delays. Upstream information also needs to be updated appropriately in response to changes in reality, such as base years for emission scenarios. Furthermore, it is now recognized that scenarios need to be handled in a more integrated manner, including impact assessment that takes into account not only radiative forcing and climate information but also socioeconomic indicators.
Based on this recognition, after the release of the IPCC Fourth Assessment Report in 2007, the main body of scenario development shifted from the IPCC to the research community, and comprehensive scenario analysis methods were newly discussed as the IPCC catalyzed the development of scenarios.
The new scenario process addressed scenario development for socioeconomic components in parallel with Represenatative Concentration Pathway (RCP)-based climate and impact scenario development, whereas RCP was a scenario of radiative forcing associated with changes in CO2 and other concentrations, it was expanded to include a shared socioeconomic pathway to enable scenario analysis of the difficulties of mitigation and adaptation measures. Socioeconomic pathways shared socioeconomic pathways (SSPs) were studied. The results of ScenarioMIP were used extensively in WG1 of the 6th Assessment Report and were cited, albeit to a limited extent, in WG2. The process of creating new scenarios in parallel method has been completed over time.
Although the SSP is a framework for global scenarios, regional scenarios are also being studied, and a Japanese version of the SSP is being developed in Japan.
3. emulators and similar concepts and bridging between disciplines
The climate scenario of full-scale sophisticated ESMs and complementary emulators is now related to the field of real-world climate policy. A recent notable example is the development of a new framework for stochastic Social Cost of Carbon (SCC) calculations, developed in response to the recommendations of the National Academies of Sciences, Engineering, and Medicine. It is a synthesis of the findings of WG1, WG2, and WG3, in a sense, in which the emulator of WG1 evaluates the level of warming for a number of socio-economic prospects in WG3, and the results are passed to the damage function of WG2.
4. Future Prospects and Challenges
The development of machine learning and artificial intelligence has led to the expansion of impact functions and simplified climate models. Until now, cross-disciplinary scenario research required high-performance computers such as supercomputers, which required a great deal of resources. Emulators are also resource-intensive in the creation process, but once created, they do not require a great deal of resources and are expected to be used by a wider range of users. As the debate on climate change shifts to solutions, emulators that can be widely used by local governments, industry, and developing countries will become even more effective.
Scenarios, as a tool for analyzing uncertain futures, play a central role in assessing long-term climate change itself and climate policies (mitigation and adaptation measures). Climate change scenario research covers a wide range of areas, from greenhouse gas emissions, carbon cycle, climate sensitivity, and regional temperature increases and their climate impacts, and the Intergovernmental Panel on Climate Change (IPCC) research community in several Working Groups (WG1, WG2, and WG3) has collaborated to conduct comprehensive analyses. This paper reviews the cross-disciplinary scenario research initiated by the IPCC's new scenario process from the perspective of international and domestic trends, with a particular focus on emulators and the related concepts (e.g., Global Warming Level). Much of this paper is based on our recent review published elsewhere.
2. current status of scenario research
The IPCC has been using a variety of scenarios, such as SA90, IS92, and SRES (Special Report on Emissions Scenarios) , depending on the time period. Various scenarios have been used depending on the time period. In particular, the SRES scenarios, which appeared in 2000, have played an important role in several IPCC assessment reports. At the same time, however, various problems have been recognized. Various elements of the scenarios are exchanged as input-output data among the research community representing each working group. Therefore, the impact assessment community downstream in the information exchange flow is affected by information delays. Upstream information also needs to be updated appropriately in response to changes in reality, such as base years for emission scenarios. Furthermore, it is now recognized that scenarios need to be handled in a more integrated manner, including impact assessment that takes into account not only radiative forcing and climate information but also socioeconomic indicators.
Based on this recognition, after the release of the IPCC Fourth Assessment Report in 2007, the main body of scenario development shifted from the IPCC to the research community, and comprehensive scenario analysis methods were newly discussed as the IPCC catalyzed the development of scenarios.
The new scenario process addressed scenario development for socioeconomic components in parallel with Represenatative Concentration Pathway (RCP)-based climate and impact scenario development, whereas RCP was a scenario of radiative forcing associated with changes in CO2 and other concentrations, it was expanded to include a shared socioeconomic pathway to enable scenario analysis of the difficulties of mitigation and adaptation measures. Socioeconomic pathways shared socioeconomic pathways (SSPs) were studied. The results of ScenarioMIP were used extensively in WG1 of the 6th Assessment Report and were cited, albeit to a limited extent, in WG2. The process of creating new scenarios in parallel method has been completed over time.
Although the SSP is a framework for global scenarios, regional scenarios are also being studied, and a Japanese version of the SSP is being developed in Japan.
3. emulators and similar concepts and bridging between disciplines
The climate scenario of full-scale sophisticated ESMs and complementary emulators is now related to the field of real-world climate policy. A recent notable example is the development of a new framework for stochastic Social Cost of Carbon (SCC) calculations, developed in response to the recommendations of the National Academies of Sciences, Engineering, and Medicine. It is a synthesis of the findings of WG1, WG2, and WG3, in a sense, in which the emulator of WG1 evaluates the level of warming for a number of socio-economic prospects in WG3, and the results are passed to the damage function of WG2.
4. Future Prospects and Challenges
The development of machine learning and artificial intelligence has led to the expansion of impact functions and simplified climate models. Until now, cross-disciplinary scenario research required high-performance computers such as supercomputers, which required a great deal of resources. Emulators are also resource-intensive in the creation process, but once created, they do not require a great deal of resources and are expected to be used by a wider range of users. As the debate on climate change shifts to solutions, emulators that can be widely used by local governments, industry, and developing countries will become even more effective.