The Legal Foundations for Fossil Fuel Phaseout: An Open Letter to the Co-Hosts and Participants of the First Conference on Transitioning Away from Fossil Fuels

The document asserts that the phaseout of fossil fuels is a legal requirement under customary international law, human rights law, the law of the sea, and climate treaties like the Paris Agreement. It argues that States must use all available means to prevent significant climate harm, including curbing fossil fuel production, licensing, and subsidies. The authors emphasize that developed States bear a higher burden of responsibility and must provide financial and technological support to developing nations for a just transition. Furthermore, the letter claims that climate obligations are 'erga omnes' and should take precedence over investor-state dispute settlement (ISDS) claims.

• States are bound by multiple sources of international law to phase out fossil fuels, including customary international law, human rights law, international environmental law, the law of the sea, and treaties such as the UNFCCC and the Paris Agreement.
• Under customary international law, States must prevent significant transboundary environmental harm by regulating public and private actors to curb fossil fuel production, consumption, licensing, and subsidies.
• Human rights law requires the phaseout of fossil fuels because the right to a healthy environment is a prerequisite for other human rights, and States must prevent foreseeable climate harm to these rights.
• The UN Convention on the Law of the Sea (UNCLOS) obliges States to curb fossil fuel use because greenhouse gas emissions are recognized as a form of marine pollution.
• Developed States have a more demanding legal duty to prevent climate harm and must provide finance, technology, and capacity-building to developing countries, LDCs, and SIDS to support a just transition.
• Fossil fuel expansion is considered presumptively contrary to legal duty, and all States, particularly large producer States, are required to halt such expansion as a preventive measure.
• Climate obligations are 'erga omnes' (owed to the international community as a whole) and should not be overridden by obligations to foreign investors under international investment treaties or Investor-State Dispute Settlement (ISDS) mechanisms.

APA

Center for International Environmental Law (n.d.). The Legal Foundations for Fossil Fuel Phaseout: An Open Letter to the Co-Hosts and Participants of the First Conference on Transitioning Away from Fossil Fuels. https://www.ciel.org/wp-content/uploads/2026/04/fossil_fuel_phaseout_legal_letter_santa_marta.pdf.pdf

Chicago

Center for International Environmental Law. The Legal Foundations for Fossil Fuel Phaseout: An Open Letter to the Co-Hosts and Participants of the First Conference on Transitioning Away from Fossil Fuels. n.d. https://www.ciel.org/wp-content/uploads/2026/04/fossil_fuel_phaseout_legal_letter_santa_marta.pdf.pdf.

Wikipedia

{{cite press release |author=Center for International Environmental Law |title=The Legal Foundations for Fossil Fuel Phaseout: An Open Letter to the Co-Hosts and Participants of the First Conference on Transitioning Away from Fossil Fuels |url=https://www.ciel.org/wp-content/uploads/2026/04/fossil_fuel_phaseout_legal_letter_santa_marta.pdf.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@misc{centerforinternationalenvironmentallawndlegal, author = {{Center for International Environmental Law}}, title = {{The Legal Foundations for Fossil Fuel Phaseout: An Open Letter to the Co-Hosts and Participants of the First Conference on Transitioning Away from Fossil Fuels}}, publisher = {Center for International Environmental Law}, url = {https://www.ciel.org/wp-content/uploads/2026/04/fossil_fuel_phaseout_legal_letter_santa_marta.pdf.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }