World Court Climate Change Opinion Validates Trump’s Paris Agreement Concerns

On July 23, the International Court of Justice released its Advisory Opinion relating to the Obligations of States in respect of Climate Change. The Court found that developed countries, like the United States, must take action to reduce GHG emissions to meet the goals of the Paris Agreement. Those countries could also be required to pay reparations to developing countries that are “adversely impacted” by the effects of climate change. The opinion, while non-binding, gives teeth to the Paris Agreement and reinforces many concerns expressed by President Trump.

The Paris Agreement is an international treaty adopted in 2015 to address the impacts of climate change. The agreement sets a goal of reaching net-zero GHG emissions by 2050. To reach that goal, a series of policies were adopted to address how governments and businesses reduce and report GHG emissions. It also focused on funding of both climate change initiatives and the economic impacts of climate change.

In 2019, President Trump withdrew the U.S. from the treaty, only for President Joe Biden to rejoin in 2021. On January 20, 2025, Trump signed an executive order to withdraw the U.S. from the agreement for a second time.

The justifications can be found in a June 2017 statement by Trump.

“There are serious legal and constitutional issues as well. Foreign leaders in Europe, Asia, and across the world should not have more to say with respect to the U.S. economy than our own citizens and their elected representatives. Thus, our withdrawal from the agreement represents a reassertion of America’s sovereignty…

“The risks grow as historically these agreements only tend to become more and more ambitious over time. In other words, the Paris framework is a starting point — as bad as it is — not an end point. And exiting the agreement protects the United States from future intrusions on the United States’ sovereignty and massive future legal liability. Believe me, we have massive legal liability if we stay in.”

That legal liability has become a reality.

In March 2023, at the request of Vanuatu, the UN General Assembly asked the ICJ to issue an advisory opinion on the legal obligations of countries in preventing climate change. The opinion gives an indicator of how the Court may interpret future climate related litigation and guide future legislative development. Following two years of proceedings, including both written and oral statements, the Court issued its opinion, and a shorter summary of the opinion, on July 23.

The opinion started with the obligations in the United Nations Framework Convention on Climate Change, the Kyoto Protocol, and the Paris Agreement. During the proceedings, a divide was formed between large, developed countries and developing countries.

One particular legal debate related to the obligations states have under the Paris Agreement. Article 4, paragraph 2 of the Agreement requires countries to “prepare, communicate and maintain successive nationally determined contributions that it intends to achieve. Parties shall pursue domestic mitigation measures, with the aim of achieving the objectives of such contributions.”

These NDCs outline actions taken by the the countries to reduce GHG emission. Throughout the Court’s proceedings, this process was been referred to as procedural, meaning that countries are only required to go through the process of creating the report. Notably, this argument was made by attorneys representing the Biden Administration.

The debate arises over whether there is a substantive, or actual action, required to enact the goals of the NDC. A substantive requirement creates a legal liability to act and could lead to legal consequences for failure to act.

To justify the substantive argument, advocates point to Article 4, paragraph 3 that states successive NDCs “will represent a progression beyond the Party’s then current nationally determined contribution and reflect its highest possible ambition, reflecting its common but differentiated responsibilities and respective capabilities, in the light of different national circumstances.”

Developing countries also argued that the goal of net zero GHG emissions by 2050, and the goal to limit global warming to 1.5 C are aspirational and not legally binding. However, the Court disagreed.

The Court determined that NDCs, steps to reduce GHG emissions, and the 1.5 C target are not aspirational, rather countries have a legal obligation to meet those goals. Further, the Court said failure to act could bring legal liability.

According to the Court, if developed countries fail to take action to mitigate the impacts of climate change, developing states that are “adversely impacted” by climate change can take legal action. If successful, high GHG emitting countries will have a “duty to make reparation.” Reparation can come in the form of restitution, like “reconstructing damaged or destroyed infrastructure, and restoring ecosystems and biodiversity”, or compensation.

While the ICJ’s Advisory Opinion relating to the Obligations of States in respect of Climate Change was non-binding, it will be used as a strong legal argument in future cases. Expect a wave of litigation relating to climate change. It will not take long for developing countries to file complaints before the ICJ seeking damages from the United States, China, Australia, and the European Union. Activists will also use the opinion in national courts to challenge both the actions of governments and of companies.