What Does the International Court of Justice Advisory Opinion on Climate Change Mean for International Investment Law?

The ICJ's 2025 Advisory Opinion establishes that states have binding legal obligations to protect the climate system, which includes phasing out fossil fuel production and subsidies. This finding challenges the legal basis for many investor-state claims, as it undermines the 'legitimate expectations' of investors in carbon-intensive industries and provides states with stronger defenses against claims of fair and equitable treatment (FET) violations. The brief argues that the prospect of ISDS can cause 'regulatory chill,' deterring necessary climate action. It recommends that states reform investment treaties through sector-based carve-outs, restrict forward-looking damages based on projected fossil fuel revenues, and coordinate withdrawals from outdated agreements like the Energy Charter Treaty.

• The ICJ determined that climate action is a binding legal obligation rather than a discretionary policy choice, specifically including the regulation of fossil fuel production, licensing, and subsidies.
• The ICJ characterized climate obligations as 'erga omnes' (owed to the international community as a whole), which weakens investor arguments that they had legitimate expectations for regulatory stability in fossil fuel activities.
• Judges Bhandari and Cleveland stated that fulfilling climate obligations necessitates a rapid reduction and phase-out of fossil fuel production and dependency, and that environmental impact assessments must include Scope 3 emissions.
• The ICJ's recognition of 'regulatory chill'—where the threat of ISDS deters states from implementing climate regulations—legitimizes the argument for reforming treaty regimes that impede climate compliance.
• The ICJ opinion strengthens state defenses against Fair and Equitable Treatment (FET) claims by establishing that investors cannot expect states to maintain regulatory frameworks that violate binding international climate obligations.
• Traditional 'fair market value' compensation standards are challenged because they often use discounted cash flow methods that ignore the reality of stranded assets resulting from inevitable climate laws.
• The brief recommends that states implement sector-based or measure-based carve-outs in investment treaties to exclude lawful climate measures from compensation claims.
• States withdrawing from the Energy Charter Treaty remain vulnerable to arbitration for 20 years under its sunset clause, necessitating binding inter se agreements to neutralize this risk.

APA

Schaugg, L. (2026). What Does the International Court of Justice Advisory Opinion on Climate Change Mean for International Investment Law? International Institute for Sustainable Development. https://www.iisd.org/system/files/2026-03/icj-advisory-opinion-international-investment-law.pdf

Chicago

Schaugg, Lukas. What Does the International Court of Justice Advisory Opinion on Climate Change Mean for International Investment Law? International Institute for Sustainable Development, 2026. https://www.iisd.org/system/files/2026-03/icj-advisory-opinion-international-investment-law.pdf.

Wikipedia

{{cite report |last1=Schaugg |first1=Lukas |title=What Does the International Court of Justice Advisory Opinion on Climate Change Mean for International Investment Law? |publisher=International Institute for Sustainable Development |date=March 2026 |url=https://www.iisd.org/system/files/2026-03/icj-advisory-opinion-international-investment-law.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{schaugg2026what, author = {Schaugg, Lukas}, title = {{What Does the International Court of Justice Advisory Opinion on Climate Change Mean for International Investment Law?}}, institution = {International Institute for Sustainable Development}, year = {2026}, month = mar, url = {https://www.iisd.org/system/files/2026-03/icj-advisory-opinion-international-investment-law.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }