Ayumi Onuma

Dr. Ayumi Onuma

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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 March 2025 in Sustainability
Verified
Journal Article
Open access
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YCYee Keong Choy
Yee Keong Choy
AOAyumi Onuma
Ayumi Onuma
KLKhai Ern Lee
Khai Ern Lee
Circular economic strategies have been widely deployed across the world to decouple industrial–urban growth from resource use and carbon emissions, aiming to mitigate environmental degradation. Despite these efforts, the global circularity gap has widened, and widespread crisis-ridden environmental repercussions continue to drive our planetary system closer to ecosystem collapse and climate breakdown. This article critically analyzes this circularity paradox based on an integrated conceptual framework grounded in environmental economic principles, system theory, the laws of thermodynamics, and empirical case studies. The analysis elucidates the macro-level dynamics and intricate feedback mechanisms between industrial–urban systems and environmental systems, revealing the underlying ecological conflicts and environmental forces that drive deleterious changes in ecosystems and the climate system. These changes causally impede sustainable industrial–urban development. The findings underscore that addressing environmental threats to industrial–urban sustainability requires not only enhancing the efficient use and sustainable management of natural resources but, more importantly, prioritizing the preservation and restoration of ecosystem resilience and climate system stability.

Verified
Journal Article
Open access
PDF file
YCYee Keong Choy
Yee Keong Choy
AOAyumi Onuma
Ayumi Onuma
Tropical peatlands store approximately 105 gigatons of carbon (GtC), serving as vital long-term carbon sinks, yet remain critically underrepresented in climate policy. Indonesia peatlands contain 57GtC—the largest tropical peatland carbon stock in the Asia–Pacific. However, decades of drainage, fires, and lax enforcement practices have degraded vast peatland areas, turning them from carbon sinks into emission sources—as evidenced by the 1997 and 2015 peatland fires which emitted 2.57 Gt CO2eq and 1.75 Gt CO2eq, respectively. Using system theory validated against historical data (1997–2023), we develop a causal loop model revealing three interconnected feedback loops driving irreversible collapse: (1) drainage–desiccation–oxidation, where water table below −40 cm triggers peat oxidation (2–5 cm subsistence) and fires; (2) fire–climate–permafrost, wherein emissions intensify radiative forcing, destabilizing monsoons and accelerating Arctic permafrost thaw (+15% since 2000); and (2) economy–governance failure, perpetuated by palm oil’s economic dominance and slack regulatory oversight. To break these vicious cycles, we propose a precautionary framework featuring IoT-enforced water table (≤40 cm), reducing emissions by 34%, legally protected “Global Climate Stabilization Zones” for peat domes (>3 m depth), safeguarding 57 GtC, and ASEAN transboundary enforcement funded by a 1–3% palm oil levy. Without intervention, annual emissions may reach 2.869 GtCO2e by 2030 (Nationally Determined Contribution’s business-as-usual scenario). Conversely, rewetting 590 km2/year aligns with Indonesia’s FOLU Net Sink 2030 target (−140 Mt CO2e) and mitigates 1.4–1.6 MtCO2 annually. We conclude that integrating peatlands as irreplaceable climate infrastructure into global policy is essential for achieving Paris Agreement goals and SDGs 13–15.

15 April 2022 in Sustainability
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Journal Article
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TTTakahiro Tsuge
Takahiro Tsuge
YSYasushi Shoji
Yasushi Shoji
KKKoichi Kuriyama
Koichi Kuriyama
AOAyumi Onuma
Ayumi Onuma
With the increase in disasters due to climate change, there has been a growing interest in green infrastructures that utilize nature for disaster risk reduction (DRR). However, green infrastructures cannot completely protect against hazards. Therefore, this study investigates the public preference in Japan for DRR and its uncertainty using a survey-based choice experiment. The results showed that benefits were obtained from the increase in “success probability”, “reduction in human damage”, “reduction in property damage”, and “reduction in indirect damage”; however, the benefits obtained from additional improvements diminished. Moreover, the results of our analyses revealed that preferences for DRR and its uncertainty were heterogeneous among respondents, and the population segment that includes more women, older people, and more people who live in areas that may be directly affected by floods had higher ratings for “success probability” and relatively slightly lower ratings for “reduction in indirect damage”.

30 August 2021 in Sustainability
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Journal Article
Open access
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YCYee Keong Choy
Yee Keong Choy
AOAyumi Onuma
Ayumi Onuma
Balancing economic growth with international commitments to environmental sustainability is a global challenge. One of the main objectives of this study is to address this challenge by stimulating and sustaining motivation for environmental conservation by means of a comprehensive rethinking of the values inherent in nature and the limitations of monetary approaches to biodiversity valuation. This is achieved based on a case study of a transboundary ecological conservation project, the Heart of Borneo (HoB) in Borneo Island, covering Kalimantan in Indonesia, Borneo Malaysia comprising the states of Sarawak and Sabah, and Brunei Darussalam. This study synthesizes critical insights into the multiple ranges of life-supporting environmental values embedded in the HoB natural capital to enhance stronger motivations for environmental conservation. The study also reports on evidence gathered from extensive field studies conducted in Borneo Malaysia, confirming the correlations between environmental beliefs in value pluralism, ecological action, and environmental sustainability, and its implications for sustainable resource use and management. The synthesis is expected to serve as practical guidance for sustainable resource and environmental management decision-making, which is conceptually and universally applicable.

19 November 2024 in International Journal of Disaster Risk Reduction
Verified
Journal Article
Open access
YOYui Omori
Yui Omori
KKKoichi Kuriyama
Koichi Kuriyama
TTTakahiro Tsuge
Takahiro Tsuge
AOAyumi Onuma
Ayumi Onuma
YSYasushi Shoji
Yasushi Shoji

31 August 2011 in Environment and Development Economics
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Journal Article
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AOAyumi Onuma
Ayumi Onuma
YAYosuke Arino
Yosuke Arino
Adaptation has the attributes of a private good that aims to protect a country from climate change, while mitigation, which contributes to the reduction of worldwide greenhouse gas emissions, has the properties of a public good. This paper attempts to investigate how the innovation of adaptation technology by a developed country (the North) may affect a developing country (the South) as well as the North through changes of mitigation in both countries. We show that the efficacy of adaptation determines the level of both countries' mitigation, and thereby causes them to be better or worse off. For both countries to be better off, it is required that the innovation be neither very effective nor very ineffective. Furthermore, we demonstrate that by introducing an international transfer system in which the North is taxed according to the level of adaptation, both countries can be better off even if the innovation is highly effective.