I. Introduction

This section discusses climate change as a key issue in global governance and international security governance, particularly its significance within the Quadrilateral Security Dialogue (QUAD) among the U.S., Japan, India, and Australia. QUAD has incorporated climate change into its political agenda, strengthening non-traditional security cooperation through discussions on public health, infrastructure development, and maritime security. Although the climate agenda was not explicitly mentioned after Trump's return to the White House, related energy and supply chain issues remain a focus for the Quad. Existing research has paid insufficient attention to QUAD's climate security cooperation. This study aims to analyze bilateral and multilateral statements, official documents, energy and carbon emission data, etc., to reveal the characteristics and challenges of the Quad's climate cooperation, contributing academically to non-traditional security research. Key research questions include how climate change has become a security priority for the Quad, whether climate security could deepen their strategic cooperation, and whether it might expand to other security domains. By examining the motivations and conditions driving climate securitization in the U.S., Japan, India, and Australia, this study seeks to understand the strategic goals and inherent features of the Quad's climate securitization, enriching research on Quad security mechanisms and global/regional climate governance.

II. Climate Security Cooperation Among the U.S., Japan, India, and Australia

Vertically, the Quad's climate security cooperation covers climate ambition targets, shipping and port industries, clean energy, carbon market mechanisms, infrastructure development, and disaster resilience. Horizontally, it strengthens regional cooperation in the Asia-Pacific, aligning with the U.S. "Indo-Pacific Strategy," the G7 "Climate Club," and Pacific regionalism. The institutionalization of QUAD accelerates security cooperation, focusing on climate change and related security issues. Quad climate cooperation primarily manifests in three areas: emission reduction targets, energy policies, and climate adaptation. Net-zero targets serve as the foundational direction, energy policies and low-carbon industrial planning are key pathways, and climate adaptation and resilience are major components. Quad climate cooperation forms regional institutional coordination and action responses with the U.S. "Indo-Pacific Strategy," the G7 "Climate Club," and the Pacific Islands Forum.

III. Motivations for Climate Security Cooperation Among the U.S., Japan, India, and Australia

The Quad's climate security cooperation stems from concerns about climate change and weak response capacities in the Asia-Pacific, aiming to expand regional influence and leadership. The four countries actively respond to climate issues and moral appeals, demonstrating cooperative potential. The Asia-Pacific is a hotspot for climate change, with cooperation rooted in joint responses to natural disasters like the 2004 Indian Ocean tsunami. The COVID-19 pandemic heightened awareness of non-traditional security, creating an opportunity for Quad mechanisms. Climate change has become a key agenda in Quad leaders' dialogues, with the Asia-Pacific facing severe climate risks that critically impact global climate governance. As major greenhouse gas emitters, the four countries fall short of Paris Agreement targets. Climate issues drive Quad energy security cooperation, focusing on energy consumption, exports, and clean energy technology collaboration. Infrastructure development is a key aspect of energy cooperation, closely tied to disaster resilience. Maritime transport in the Indian and Pacific Oceans is vital for regional energy security. Clean energy technology and low-carbon development are central to Quad energy cooperation, emphasizing global clean energy supply chains, energy security, and carbon-free fuels. Cooperation must align with each country's clean energy policies and climate action pathways.

IV. Climate Governance Challenges for the U.S., Japan, India, and Australia

The four countries face political, economic, and energy-related challenges in climate governance, limiting climate security cooperation. Significant disparities exist in greenhouse gas emissions, climate risks and response capacities, international climate governance stances, and energy structures. Domestic politics constrain climate actions, making global commitments and net-zero targets difficult to synchronize. The U.S., Japan, and Australia, part of the traditional "umbrella group," have been passive on emission reductions. India, as a developing country, defends developing nations' rights in climate negotiations, emphasizing "common but differentiated responsibilities." Fossil fuels dominate their energy structures, but energy industries vary: the U.S. is a major energy consumer, importer, and producer; Australia relies on energy and resource industries; Japan depends heavily on fossil fuel imports; and India is a major energy importer and consumer. Attitudes toward climate finance and technology differ: the U.S. has been reluctant to lead or fund global climate efforts, Japan actively provides climate and environmental funding, and India urges developed nations to fulfill financial commitments. Key Asia-Pacific countries are absent from the Quad's climate action platform, reducing its regional representativeness.

V. Impacts of Climate Security Cooperation Among the U.S., Japan, India, and Australia

Quad climate security cooperation has multifaceted global governance impacts: elevating non-traditional security issues, enhancing U.S. leadership in the Asia-Pacific through economic aid and infrastructure, and making maritime security a key Quad issue. Climate change expands Quad security mechanisms. Pacific small island states' regionalism grows, with Australia actively responding to climate demands. Climate securitization affects clean technology and trade; the Quad boosts regional low-carbon cohesion through tech cooperation, while clean energy products face anti-dumping measures. The U.S. supports carbon border adjustments. The Quad promotes green shipping and carbon markets, shaping low-carbon rules and standards that impact Chinese industries. Emerging issues like climate change help the Quad extend influence into Southeast Asia, fracturing developing-world solidarity and challenging China's role. Quad climate securitization blurs developed-developing nation responsibility divides, weakening the "common but differentiated" principle and undermining international climate governance.

VI. Conclusion

QUAD integrates climate issues with security agendas, making climate securitization a cooperation focus. Loss and damage have become central to UN climate talks, long urged by Asia-Pacific small island states. As global climate governance evolves, Quad climate security agendas may expand to include historical responsibility issues. For China, impacts involve climate cooperation, energy security, and development space. China's influence among developing nations may face pressure as Quad cooperation divides negotiation blocs. Belt and Road projects could come under scrutiny amid climate securitization, with infrastructure facing constraints. The exclusivity of Quad low-carbon models warrants observation, as regional carbon markets may affect Chinese industries and exports. QUAD's climate agenda institutionalization offers cooperation opportunities but varies due to internal national differences.