The climate change crisis has emerged as a fundamental challenge to contemporary international law, placing the international investment regime under increasing normative and institutional strain. Bilateral Investment Treaties, originally designed to ensure legal certainty and regulatory stability for foreign investors, increasingly intersect with state climate policies that are inherently dynamic, precautionary, and based on evolving regulatory frameworks. This tension raises a central research question: how can investment treaty obligations be reconciled with the requirements of international climate law without unduly undermining legal certainty for investors?

The objective of this study is to examine the systemic nature of the conflict between international investment law and climate governance and to assess the necessity of revisiting investment treaties in light of climate imperatives. Employing a descriptive-–analytical methodology, the research analyses treaty standards, regulatory practices, and investment arbitration jurisprudence to identify structural points of friction between the two regimes.

The findings demonstrate that static and investor-centric interpretations of investment treaty standards particularly fair and equitable treatment and indirect expropriation risk constraining states’ regulatory autonomy and weakening the implementation of climate policies. The study concludes that the long-term legitimacy and sustainability of the international investment regime depend on a recalibrated interpretative and structural approach that integrates climate obligations, preserves the state’s right to regulate, and aligns investment protection with climate justice and sustainable development.