Interview: Former UN Special Rapporteur David Boyd hails ‘unprecedented clarity’ of ICJ climate ruling
The 30th Conference of the Parties concluded in Brazil this month, with delegates focused on reinforcing the 2015 Paris Agreement’s goal of limiting global warming to 1.5°C. Central to this year’s negotiations: pressing member states to commit to more ambitious Nationally Determined Contributions, or NDCs.
In the lead-up to COP30, JURIST spoke with Dr. David R. Boyd, the former UN Special Rapporteur on human rights and the environment, about how a recent International Court of Justice advisory opinion could shape the talks.
The ICJ issued an advisory opinion in late July affirming that state obligations under the Paris Agreement—including the 1.5°C target—are binding commitments. The court also found these conventions inform customary obligations owed by non-party states.
In this interview, conducted ahead of COP30, Boyd discussed how the advisory opinion stood to shift negotiating dynamics and influence climate litigation both domestically and internationally.
JURIST: If you have to pick one, what part of the Advisory Opinion do you like most?
Boyd: If I have to pick one, I will say that the court has unanimously rejected a persistent argument raised by the wealthy states – the lex specialis argument. These states have always contended that obligations of states in respect of climate change are contained within the walls of the climate change treaties – the United Nations Framework Convention on Climate Change (UNFCCC), the Paris Agreement and the Kyoto Protocol. Similar to other highly regarded courts, such as the European Court of Human Rights, the Inter-American Court of Human Rights and the International Tribunal for the Law of the Sea, the International Court of Justice has affirmed that these climate change treaties are just part of the broader corpus of international law that regulates state obligations in respect to climate change. Other sources include international human rights law, customary international law and general principles of international law. This ruling has provided unprecedented clarity to international environmental law, after 33 years of contested interpretation since the Rio Earth Summit in 1992.
JURIST: What’s one issue you think the court could have gone further on?
Boyd: The court has only done a partial job in affirming the right to a clean, healthy and sustainable environment. In a few separate opinions, several members of the court were concerned with the ruling’s failure to clarify the formal status of the right – whether it is customary international law, a general principle of international law, or jus cogens. The unanimous advisory opinion also did not affirm the procedural and substantive content of the right.
JURIST: Could you give us a brief introduction of what the right to a clean, healthy and sustainable environment is?
Boyd: For sure. The right to a clean, healthy and sustainable environment is not a new human right. As of today, 165 states recognize the right in their domestic law, whether through constitutional provisions, legislation, or ratification of a regional treaty. The right to a healthy environment is comprised of procedural and substantive elements. The procedural element is also known as the toolbox for litigants to enforce their rights, including access to information, public participation and access to justice with effective remedies. On the other hand, the substantive elements require states to secure clean air, safe and sufficient water and adequate sanitation, healthy and sustainably produced food, a non-toxic environment, healthy ecosystems and biodiversity and a safe climate. I must highlight to your readers that members of the court have unanimously agreed on the existence of the fundamental right to a clean, healthy and sustainable environment under international law. This is highly unusual, as only a handful of ICJ decisions have produced unanimous opinions in the Court’s 75-year history. It is also very powerful, given that some of the world’s largest and most powerful states (e.g. United States, Russia, Germany) argued before the ICJ that the right to a healthy environment did not exist at all in international law.
JURIST: In a 2024 interview, you mentioned you remained optimistic about the right in the US and the UK. With the current US administration withdrawing from the Paris Agreement again, are you still optimistic about the right in the US?
Boyd: The US, being one of the largest greenhouse gas emitters, withdrawing from the Paris Agreement is a disastrous situation indeed. However, it is fortunate that the International Court of Justice has now affirmed that state obligations in respect of climate change are not limited to those flowing from the treaties. While I am not optimistic about the right at the federal level, we can still observe efforts made by state and municipal governments. While Vermont and other states are considering amendments to their state constitutions to include the right to a healthy environment, New York has already had the right enshrined in its state constitution in 2022. These states have also enacted legislation requiring fossil fuel companies to compensate state governments for the economic costs of adapting to the climate crisis. There are also lawsuits at state courts seeking to enforce the right. For instance, the Hawaiian government reached a historic settlement with a group of youth litigants, with a commitment to transform the state’s transportation system to reach net-zero emissions by 2045. The youth activists are also allowed to oversee the implementation of Hawaii’s transportation strategy. From these kinds of cases, we see that youth activists have been a strong contributing force towards progress in climate change and that’s one reason we can remain optimistic.
JURIST: In the same interview, you mentioned the potential addition of the right to the Universal Declaration of Human Rights. Now that the ICJ has affirmed the existence of the right, do you think this will happen in the foreseeable future? With the right now affirmed by the court, what will be the legal significance of adding the right to the Declaration?
Boyd: Yes, I am optimistic about seeing the right being added to the Declaration in the short term. From the conversations I had with several governments, they have all been supportive of including the right in the Declaration. Even though the Declaration is not legally binding, it remains a very powerful instrument that is indicative of how fundamental human rights are at international law.
JURIST: Do you foresee any concrete mechanism (perhaps akin to UNHRC periodic observations) regarding the right to a clean environment to be drawn up in the upcoming COP?
Boyd: As much as I would love to see an enforcement mechanism drawn up in the upcoming COP30, I don’t think state parties will be able to reach a consensus on this matter. However, the advisory opinion has fundamentally changed the negotiating dynamics. We will see a bloc of states that respect the opinion of the court and seek to enforce the opinion through political negotiations during COP30. The law is now clearly on the side of the Small Island Developing states and other climate vulnerable nations. On the other hand, there will be countries, mostly large emitters, challenging how we should understand the advisory opinion. What kinds of decisions will be made at COP30 by state parties remains to be seen because of the clash between politics and law.
JURIST: Now that the commitments states make in COP decisions will be legally binding, will that discourage state parties from taking ambitious commitments?
Boyd: No. For example, Nationally Determined Contributions (NDCs) are one of the cornerstones of the Paris Agreement. For a decade, large emitters have argued that there is a procedural duty to file NDCs but no legal obligations related to their substance. Now, the International Court of Justice ruled that the NDCs must reflect the state’s highest possible ambition and must collectively contribute to achieving the 1.5°C limit in the Paris Agreement. NDCs must also include effective and equitable measures that are capable of achieving the targets set by states. Ideally states will submit strengthened NDCs. If they fail to do so, the advisory opinion provides a strong legal foundation for climate change litigation to ensure each state does its fair share. And in my opinion, a number of countries that filed their NDCs earlier in the year before the advisory opinion do not meet the substantive requirements articulated by the ICJ. For instance, Canada has not demonstrated how its latest NDC, filed in February 2025, represents its highest possible ambition and its fair share. If wealthy countries do not demonstrate their best possible efforts in their climate change adaptation and mitigation measures as required, we can foresee an unprecedented wave of litigation, both within a country and between states. As I said, the advisory opinion has really changed the negotiation dynamics. Small island states and other climate vulnerable nations now come to COP30 with very high expectations. The wealthy nations now have to choose between making their highest possible effort that contributes towards achieving the Paris Agreement objectives or facing litigation that could result in a range of international law remedies arising from their breach of international obligations.
JURIST: Canada has amended its Canadian Environmental Protection Act (CEPA) to recognize domestically the right to a clean, healthy and sustainable environment. Yet, it is not a fundamental right enshrined in the Canadian Charter of Rights and Freedoms. Does this put the right in an inferior position? What are the gaps, if any, in protecting the right in CEPA, compared to recognizing the right in the Charter?
Boyd: You are probably aware that I wrote a whole book on this. The simple answer to this question is – having the right recognized in CEPA is definitely a legal step forward, but not as powerful as it could be if it is enshrined in the Charter. There are two main limitations. First, as CEPA is federal legislation, the right is only recognized at the federal level. The provincial governments are not bound by CEPA. Second, the right is only recognized within the bounds of CEPA. There is other related legislation in Canada that affects the right to a healthy environment but is not in CEPA. For instance, actions taken pursuant to the Pest Control Products Act may implicate the right to healthy and sustainably produced food and a non-toxic environment, but a violation of the right to a healthy environment could not be a cause of action against government actions stemming from the act because it is not within the bounds of CEPA.
Though many may consider the notion of human rights vague and distant from their everyday life, recognizing the right in CEPA has generated great potential in changing government policies and Canadians’ way of life. Shortly after Canada amended CEPA in 2023 to explicitly recognize the right to a healthy environment, the Minister of the Environment made an Interim Order in May 2024 to regulate benzene emission from petrochemical facilities in Sarnia, Ontario and protect the Aamjiwnaang First Nation community from benzene exposure in the short term. This important action was a direct result of the right to a healthy environment.
JURIST: Now that Canada owes an international obligation to set its NDC contributing to the 1.5°C goal of the Paris Agreement, how should Canadian courts balance their judicial involvement in overall policy and the protection of the right to a healthy environment?
Boyd: There are currently two ongoing climate change lawsuits in Canada – La Rose v Canada and Mathur v Ontario – both contend that the right to a healthy environment is implicit in the right to life, liberty and security under section 7 of the Charter. This argument is not novel and has been accepted by domestic courts in more than a dozen other nations, including the Supreme Court of India and the Supreme Court of Argentina. The advisory opinion has given more momentum to the pending cases in Canada. There is now a much greater likelihood that the court will accept this argument, representing a huge step forward in Canadian environmental law and human rights law.
The courts play a critical role in protecting human rights from state infringement, there is no doubt of that. It is one of the judiciary’s most important responsibilities. What could be considered a potential judicial overreach would occur if a court told the government specifically what target should be set to satisfy its international obligations. That is unlikely to happen in a Canadian court. Germany sets an example that courts can oversee national emission reduction targets without judicial overreach. Its Federal Constitutional Court reviewed Germany’s climate legislation in 2021 and held that the government’s failure to set adequately ambitious targets created a disproportionate burden on younger generations, thus requiring the government to revise its climate legislation so that it does not violate their right to human dignity, life and physical integrity, freedom of occupation, and property. The government responded to the court’s decision by significantly strengthening the emission reduction targets in its climate legislation.
In a concluding remark, Dr. Boyd said that he remains cautiously optimistic about climate change. Although there are international actors who are hindering progress on climate change adaptation and mitigation, there are a lot of solutions that allow us to be optimistic about the future. For instance, solar and wind energy are now the most affordable sources of energy in most parts of the world, with solar energy being capable of providing 20 percent of global electricity across midday peaks. The rapid growth of electric vehicle adoption in countries like Norway, China and Nepal also gives us reasons to look beyond the bad news and give credit to the progress made.
