7. Climate Risks and the Acceleration of Population Implosion in East Asia

Rationale of the theme highlighting relevance and potential impact:

East Asia, as well as some countries in the Southeast Asia like Thailand, is currently undergoing a significant demographic transition characterized by declining fertility rates and rapidly aging populations. This pre-existing demographic trend makes the region particularly vulnerable to environmental stressors that could further impact humans. Climate change represents such a significant stressor, manifesting in East Asia through more frequent and intense extreme weather events. The increasing frequency of heatwaves and prolonged droughts, and more intensified and severe flooding, typhoons, coupled with rising sea-levels, pose substantial risks to human health, livelihoods, and overall well-being. Moreover, the climate impacts on human societies are place-based, varying across geographic locations. Meanwhile, spatial distribution of human population and their sociodemographic characteristics also differ from place to place.

Population-environment literature reveals exceptionally high risks of heat stress among living-alone elderly population left behind migration, as an example. The interplay between these climate hazards and human resilience in East Asia suggests a concerning trajectory for population stability. This Scientific Group focuses on examining climate risks in East Asia where population decline and rapid aging, as well as migration, urbanization, household formation and dissolution, improved education and health conditions as common phenomena, which generates important effects on population exposure and social vulnerability. It may also draw occasional insights from Thailand, a Southeast Asian country facing similar demographic and climate-related challenges. It will investigate the general patterns and compare the differences among the counties and the subnational regions within each country.

The Scientific Group will also analyze the multifaceted ways in which climate risks act as a catalyst, exacerbating the ongoing population implosion in East Asia. It will explore how climate change contributes to negative health impacts (e.g., increased mortality rates and potentially decreases fertility rates) and drives climate-induced migration, all of which compound the challenges posed by aging populations and low fertility rates, using methodologies, including but not limited to gridded population, big data, and multidimensional and spatial population projection. 

Chairs: Oh Seok Kim (Korea University) and Leiwen Jiang (Shanghai University)

Members: Chalermpol Chamchan (Mahidol University), Chi-Tsun Chiu (Academia Sinica), and cc (Shanghai University)

SG will address the following overarching questions over the period from June 2025 through December 2027:

• How do specific climate hazards (e.g., heatwaves, flooding, air pollution) disproportionately impact aging populations in East Asia, considering their spatial population exposure and social vulnerability?
• What are the feedback mechanisms between population implosion (e.g., shrinking labor force, declining social support networks) and the region’s capacity to adapt to and recover from climate risks?
• What are the implications of these intertwined challenges for public health systems, social welfare programs, and long-term sustainable development in East Asian nations?
• Can we identify spatial indicators and develop predictive models to forecast the synergistic impacts of climate risks and population implosion on health outcomes and regional resilience?

Objectives and provisional programme of activities that the group would like to pursue over the period from June 2025 through December 2027 are as follows:

In-person workshops and online webinars (preferably twice per year):

• Fall 2025: People-based definition of cities, human settlements along urban-rural continuum, and gridded population (in-person workshop in Shanghai) via the 4th Asian Population Forum on “Demographic Methods and Models in Global and National Development Assessment Research” and a related training workshop, entitled “Application of the Degree of Urbanization for Demographic Research and Policy Analysis” by Asian Demographic Research Institute (ADRI)
• Winter 2025: Climate Risks and the Acceleration of Population Implosion in Taiwan and South Korea (in-person workshop in Taipei) hosted by the Institute of European and American Studies, Academia Sinica (Aging and Life Course (ALC) and Farm for Change: Climate, Eco-poetics, Earth Justice (FFC) labs)
• Winter 2026: Sponsored session at the 7th APA Conference, Hanoi, Vietnam
• Spring/Summer 2027: Extreme heat, air pollution, and health impacts on older population (if funded, in-person workshop in Seoul or Taipei; if not, online webinar)
• Fall/Winter 2027: Climate impacts on population dynamics – fertility, migration, and health (online webinar)

7th APA Conference (2026):

• Paper sessions on East Asia’s population implosion and climate risks

Joint publications: 

• Special issue on Climate and Health in Spatial Demography and other journals 

Potential sources of funding and support: 

• National Research Foundation of Korea and Korea Environment Institute (in progress)

Oh Seok Kim (Geography, Ph.D., Chair)

Korea University, South Korea

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Bio: O Kim's research explores the complex interplay between environmental changes, demographic dynamics, and societal challenges in South Korea. By leveraging advanced spatial analysis, geographic information systems (GIS), and machine learning, his work addresses critical issues such as population exposure to climate-induced risks like sea-level rise, storm surges, and extreme heat events. His studies reveal that while South Korea's declining and aging population may reduce overall exposure in some areas, rapid aging amplifies vulnerability in others, particularly to heat events, with older populations projected to face up to four times greater exposure by 2060. Additionally, his research highlights the impact of demographic shifts on essential resources, such as blood supply, projecting severe shortages by 2050 and emphasizing the need for targeted strategies to address regional disparities. Prof. Kim’s work underscores the urgent need for integrated approaches to mitigate the combined effects of climate change and demographic transitions.

Selected Publications:

Kim, O. S. et al. (in preparation). Future population exposure to flooding due to sea-level rise and storm surge in South Korea where the country’s population is declining. 

Kim, O. S., Han, J., Kim, K. W., Matthews, S. A., & Shim, C. (2022). Depopulation, super aging, and extreme heat events in South Korea. Climate Risk Management, 38, 100456.

Kim, K. W., & Kim, O. S. (2020). Super aging in South Korea unstoppable but mitigatable: a sub-national scale population projection for best policy planning. Spatial Demography, 8(2), 155-173.

Kim, O. S., Ji, S., Jung, H. W., Matthews, S. A., Cha, Y. J., Moon, S. D., & Kim, K. (2024). Future blood debt: projecting blood supply and demand of Korea based on subnational population projections (2021–2050). Journal of Korean Medical Science, 39(20), e168.

Leiwen Jiang (Demography, Ph.D., Chair)

Shanghai University, China

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Bio: Leiwen Jiang is founding director and professor of the Asian Demographic Research Institute (ADRI) at Shanghai University. He also leads ADRI’s research pillar on Population, Environment and Climate Change (PECC). His research involves methodological work on improving demographic components of integrated assessment modeling on environment and climate change policies. He explores the environmental implications of socioeconomic and demographic dynamics. Prof. Jiang has been developing the Community Demographic Models (CDM) for the broader environmental and climate change research communities at the National Center for Atmospheric Research (NCAR) and the Population Council. His funded research projects explicitly explore the socio-demographic determinants of energy transition in the developing world; study the urbanization processes of different phases and forms and their effects on energy consumption, land use, greenhouse gas emissions, and wildfire risks; simulate the interactions between demographic dynamics (particularly migration) and land use and water resources; and analyze household consumption patterns and other behavioral changes and their consequences on the environment and climate systems.

Selected Publications:

Jiang, L., O’Neill, B. C., Zoraghein, H., & Dahlke, S. (2020). Population scenarios for US states consistent with shared socioeconomic pathways. Environmental Research Letters, 15(9), 094097.

O’Neill, B. C., Jiang, L., Kc, S., Fuchs, R., Pachauri, S., Laidlaw, E. K., Zhang, T., Zhou, W., & Ren, X. (2020). The effect of education on determinants of climate change risks. Nature Sustainability, 3(7), 520-528.

Abdelwahed, A., Goujon, A., & Jiang, L. (2020). The migration intentions of young Egyptians. Sustainability, 12(23), 9803.

Striessnig, E., Gao, J., O’Neill, B. C., & Jiang, L. (2019). Empirically based spatial projections of US population age structure consistent with the shared socioeconomic pathways. Environmental Research Letters, 14(11), 114038.

Jiang, L., & O'Neill, B. C. (2018). Determinants of urban growth during demographic and mobility transitions: Evidence from India, Mexico, and the US. Population and development review, (2), 363-389.

Chen, K., de Schrijver, E., Sivaraj, S., Sera, F., Scovronick, N., Jiang, L., Roye, D., Lavigne, E., Kyselý, J., Urban, A., Schneider, A., Huber, V., Madureira, J., Mistry, M. N., Cvijanovic, I., Gasparrini, A., & Vicedo-Cabrera, A. M. (2024). Impact of population aging on future temperature-related mortality at different global warming levels. Nature Communications, 15(1), 1796.

O’Neill, B. C., Jiang, L., Kc, S., Fuchs, R., Pachauri, S., Laidlaw, E. K., Zhang, T., Zhou, W., & Ren, X. (2020). The effect of education on determinants of climate change risks. Nature Sustainability, 3(7), 520-528.

Chen, K., Fiore, A. M., Chen, R., Jiang, L., Jones, B., Schneider, A., Peters, A., Bi, J., Kan, H., & Kinney, P. L. (2018). Future ozone-related acute excess mortality under climate and population change scenarios in China: A modeling study. PLoS Medicine, 15(7), e1002598.

Jiang, L., & O’Neill, B. C. (2017). Global urbanization projections for the Shared Socioeconomic Pathways. Global Environmental Change, 42, 193-199.

Chen, K., Horton, R. M., Bader, D. A., Lesk, C., Jiang, L., Jones, B., Zhou, L., Chen, X., Bi, J., & Kinney, P. L. (2017). Impact of climate change on heat-related mortality in Jiangsu Province, China. Environmental pollution, 224, 317-325.

Chalermpol Chamchan (Area Studies, Ph.D.)

Mahidol University, Thailand

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Bio: Chalermpol Chamchan is Director of the Institute for Population and Social Research (IPSR) at Mahidol University, where he also serves as Associate Professor. Trained in Economics and Area Studies, his work bridges demographic research, health policy, and social development. Prof. Chamchan’s research centers on the intersections of population dynamics, health systems, migration, and aging societies. He has led numerous nationally and internationally funded projects addressing issues such as youth and adolescent health, cross-border migrant populations, labor force participation of older persons, and socioeconomic inequalities under Thailand’s universal health coverage. His work extends to applied economics and behavioral interventions, including studies on food consumption, workplace well-being, and the economic implications of demographic transitions.

Selected Publications:

Cheewinsiriwat, P., Langkulsen, U., Lertwattanamongkol, V., Poompongthai, W., Lambonmung, A., Chamchan, C., Boonmanunt, S., Nakhapakorn, K., & Moses, C. (2024). Assessing coastal vulnerability to climate change: A case study of Nakhon Si Thammarat and Krabi. Social Sciences, 13(3), 142.

Kaikeaw, S., Punpuing, S., Chamchan, C., & Prasartkul, P. (2023). Socioeconomic inequalities in health outcomes among Thai older population in the era of Universal Health Coverage: trends and decomposition analysis. International Journal for Equity in Health, 22(1), 144.

Sangngam, J., Prasopkittikun, T., Nookong, A., Pacharn, P., & Chamchan, C. (2023). Causal relationships among self-management behaviors, symptom control, health-related quality of life and the influencing factors among Thai adolescents with asthma. International Journal of Nursing Sciences, 10(3), 309-317.

Chamchan, C., & Apipornchaisakul, K. (2022). Health insurance status of cross-border migrant children and the associated factors: a study in a Thai-Myanmar border area. BMC Health Services Research, 22(1), 1276.

Kim, N. I., Chamchan, C., & Tangchonlatip, K. (2022). Prevalence and social risk factors of infertility in Vietnam. Illness, Crisis & Loss, 30(4), 756-769.

Chi-Tsun Chiu (Sociology, Ph.D.)

Institute of European and American Studies, Academia Sinica, Taiwan

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Bio: Chi-Tsun Chiu is an Associate Research Fellow (with tenure) at the Institute of European and American Studies, Academia Sinica, Taiwan. He earned his Ph.D. in Sociology with a specialization in Demography from the University of Texas at Austin. As a social demographer specializing in health and aging, Dr. Chiu's research investigates the social determinants of health and aging. His work focuses on identifying modifiable factors that can enhance population health outcomes and reduce health disparities across different demographic groups. He is currently responsible for maintaining and updating the SPACE (Stochastic Population Analysis for Complex Events) program. He has provided training workshops at Berkeley, Ann Arbor, Singapore, Spain, Italy, and Taiwan. His user-friendly versions of the SPACE program have been adopted by researchers globally for demographic and health analyses.

Selected Publications:

Chiu, C. T. (2019). Living arrangements and disability-free life expectancy in the United States. PLoS One, 14(2), e0211894.

Chiu, C. T., Hayward, M. D., Chan, A., & Matchar, D. B. (2019). Educational differences in the compression of disability incidence in the United States. SSM-Population Health, 7, 100347.

Chiu, C. T., Yong, V., Chen, H. W., & Saito, Y. (2019). Disabled life expectancy with and without stroke: a 10-year Japanese prospective cohort study. Quality of Life Research, 28(11), 3055-3064.

Chiu, C. T., Malhotra, R., Tan, S. M., Lim, J., Chan, A., Teoh, K. H., Gan, S.T., & Saito, Y. (2017). Dental health status of community‐dwelling older Singaporeans: findings from a nationally representative survey. Gerodontology, 34(1), 57-67.

Chiu, C. T., Hayward, M., & Saito, Y. (2016). A comparison of educational differences on physical health, mortality, and healthy life expectancy in Japan and the United States. Journal of Aging and Health, 28(7), 1256-1278.

Xueting Li (Demography, Ph.D.)

Shanghai University, China

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Bio: Xueting Li holds a Ph.D. in Demography from Shanghai University, specializing in Population, Environment, and Sustainable Development. Her research examines social vulnerability to natural hazards under climate change, integrating interdisciplinary approaches to assess risk, resilience, and adaptation strategies. Her work has been published in high-impact
journals such as Population and Environment and Natural Hazards, contributing to critical discussions on climate change and policy-relevant solutions.

Selected Publications:
Li, X., & Jiang, L. (2024). Spatial and temporal changes in social vulnerability to natural hazards: a case study for China counties. Natural Hazards, 120(12), 11273-11292.

Li, X. (2024). Measuring social vulnerability to natural hazards in China: a modified index
approach. Population and Environment, 46(2), 14.