The United States filed an amicus brief in support of Suncor Energy (U.S.A.) Inc., Suncor Energy Sales Inc., and Exxon Mobil Corporation’s petition for writ of certiorari asking the U.S. Supreme Court to review the Colorado Supreme Court’s May 2025 opinion holding that federal law did not preempt claims brought by the City of Boulder and the County Commissioners of Boulder County (together, Boulder) under state law to hold the companies liable for climate change-related injuries. The U.S. contended that review by the Court was warranted because both the Constitution and the Clean Air Act barred Boulder’s state law claims and because the Colorado Supreme Court’s decision conflicted with the Second Circuit’s decision in <a href="https://www.climatecasechart.com/document/city-of-new-york-v-chevron-corp_0ef5">City of New  York v. Chevron Corp.</a> on a “frequently recurring issue of exceptional importance,” given the number of other pending cases brought by state and local governments against fossil fuel industry defendants. 

Action by Colorado local governments seeking damages and other relief from fossil fuel companies for climate change harms.

Suncor Energy (U.S.A.) Inc. v. County Commissioners of Boulder County

<p>This entry was provided by the Sabin Center for Climate Change Law. Please see the terms of use for citation and licensing of third party data.</p>

United States Filed Brief Supporting Supreme Court Review of Colorado Supreme Court Decision Allowing State-Law Climate Claims Against Fossil Fuel Companies

Filed

United States of America

Colorado

The Climate Litigation Database

Find climate change litigation data and indicators for {text}.

{text} litigation

Sabin Center for Climate Change Law provides Climate Litigation Database, a comprehensive database of US and Global climate change caselaw

Quickly and easily search through the complete text of thousands of climate change law and policy documents from every country.

Search the Climate Litigation Database

An aim to achieve a quantifiable outcome within a given time-frame, set by an institution such as a national government.

Policy instruments are techniques or tools used by governing authorities to promote certain policies in order to achieve predetermined goals. Put simply, instruments are how a government tries to achieve its goals, with this taxonomy being focused on national policy instruments.

Risk is the potential for adverse consequences resulting from the dynamic interplay between (climate-related) hazards, exposure, and vulnerability of affected human or ecological systems.

Groups  of people who are adversely affected by climate change or the response to it

A set of principles, processes, and practices that build economic and political power to shift from an extractive economy to a regenerative economy.

Justice is the ethical and political framework that addresses fairness, including issues of responsibility, rights, and structural inequity.

Renewable energy means all forms of energy produced from renewable sources in a sustainable manner.

Fossil fuel is a generic term for non-renewable energy sources such as coal, fossil gas, and oil (including crude oil, and petroleum products), that can be used for electricity and heat generation. Fossil fuels are hydrocarbons formed from pressurised and heated organic material buried over millions of years.

Molecules in the atmosphere that play a key role in the greenhouse effect by trapping heat radiating from Earth’s surface.

Area of the economy in which actors engage in identical or related activities.

In human systems, the process of adjustment to actual or expected climate change and its effects, in order to moderate harm, increase resilience or exploit beneficial opportunities. In natural systems, the process of adjustment to actual climate change and its effects; human intervention may facilitate adjustment to expected climate change and its effects.

The management and allocation of funds, assets and investments to meet various objectives

Actions or measures to adapt freshwater systems to climate change.

Actions or measures to adapt freshwater, coastal and marine systems to climate change.

Hot temperature extremes are daily maximum temperatures  that were exceeded on average once in a decade or once in 50 years, and includes heatwaves.

Extreme weather refers to events where a weather variable exceeds (or falls below) a threshold. Meaning it is significantly different from the average or usual weather pattern.

A drought is an extended period of unusually dry weather marked by a significant and sustained lack of precipitation, falling below a specific threshold over a large area for more than a month

Terrestrial means "of the earth" and relates to the risks to ecological system that includes all living organisms and their interactions within land-based environments, such as forests, grasslands, and deserts.

Air pollution involves harmful contaminants in the air, affecting both indoor and outdoor environments. It can lead to health issues like respiratory diseases and heart problems, and climate impacts such as global warming. Pollutants can damage plants, trees, habitats, and water bodies like rivers and lakes.

Oil is a combustible liquid fossil fuel composed mainly of hydrocarbons, occurring as crude oil and refined into petroleum products such as petrol, diesel and kerosene.

Fossil gas, commonly known as natural gas, is a fossil fuel consisting chiefly of methane with smaller amounts of other hydrocarbons and trace gases, found in underground deposits.

Coal is a combustible sedimentary rock formed from carbonised plant matter, rich in carbon and hydrocarbons, and occurring in several main types including hard coal and brown coal.

Any compulsory, unrequited payment to the government levied on corporations or individuals. This can be for environmental reasons, such as introducing a Carbon tax to set a price that emitters must pay for the greenhouse gases they emit.

This sector involves the wholesale and retail selling of goods.

This sector creates and distributes information and entertainment through television, radio, print, and digital platforms.

United States Filed Brief Supporting Supreme Court Review of Colorado Supreme Court Decision Allowing State-Law Climate Claims Against Fossil Fuel Companies

Policy instrument

Risk

Fossil fuel

Greenhouse gas

Economic sector

Adaptation/resilience