This article examines how climate change has shifted from being framed primarily as an environmental problem to functioning as an instrument of power, diplomacy, and strategic influence among major powers in the Indo-Pacific region. The study adopts a qualitative comparative case study design based on structured, focused comparison of three cases, namely the United States, China, and the European Union. Each cases analysed through the same four analytical dimensions of climate geopolitics: policy instrument, material power base, institutional and normative channel, and effect on the strategic autonomy of recipient states. The findings show that the United States integrates climate resilience into its Indo-Pacific security architecture through humanitarian assistance and disaster diplomacy. In contrast, China leverages the Green Belt and Road Initiative to expand economic and technological influence, while the European Union exercises regulatory and normative power through the Global Gateway and the Carbon Border Adjustment Mechanism. The comparison shows that these three actors converge in treating climate cooperation as a channel of influence but diverge in the material base of that influence, namely logistical capacity, supply-chain and financing dominance, and market-regulatory reach. This divergence is best explained by comparative advantage rather than by three distinct designs for regional dominance. The article further distinguishes declared strategic intent, which is traceable in official documents, from geopolitical consequence, which may arise irrespective of intent, and therefore does not treat all climate cooperation as deliberate manipulation. These strategies address climate risks while simultaneously generating new dependencies and bargaining dynamics for Indo-Pacific states.