As the climate crisis intensifies, communities worldwide are increasingly turning to the courts for help with the billions of dollars they spend annually to address extreme weather damages. While global climate policy has struggled to advance at the necessary scale, a growing body of loss and damage litigation offers pathways for those seeking justice. These cases aim to compensate individuals and communities for the economic and non-economic harms already occurring due to climate change—such as loss of property, livelihood, biodiversity, and cultural heritage—by pursuing claims against the world’s largest historical carbon emitters, a group of fossil fuel companies often referred to as the Carbon Majors.
As loss and damage litigation gains momentum, however, one of the biggest challenges remains the legal question of causation—whether a specific defendant’s actions were a substantial enough factor in a plaintiff’s particular harm for them to be held accountable. This can be especially challenging in cases where non-climate change factors may also be contributing to or mitigating a specific event or local trend. But one type of climate impact is emerging as a powerful focus for overcoming this hurdle: extreme heat.
The increasing magnitude, frequency, and duration of extreme heat events are among the most directly attributable consequences of human-caused climate change. In contrast to other climate impacts, such as hurricanes, which can only be said to have been made more probable or intense by climate change, scientists have been able to characterize a select number of heat-related events as “essentially impossible” without human greenhouse gas emissions. By centering extreme heat in loss and damage litigation, climate advocates can sharpen their legal arguments around causation, opening new pathways to distribute the economic burden imposed on impacted communities.
The human rights toll of extreme heat
Centering the impacts of extreme heat doesn’t just make climate lawsuits more legally viable—it also shines a light on one of the most lethal and overlooked impacts of the climate crisis. Despite receiving little attention from governments and news outlets, heat stress is the leading cause of weather-related death, and the number of people exposed to extreme heat is growing exponentially. Globally, the number of days above 95 degrees Fahrenheit is expected to increase more than threefold by 2100 in the absence of significant greenhouse gas emission reductions. Even under the most optimistic climate projections, temperatures are expected to rise, with devastating consequences for human health and well-being, particularly among vulnerable populations.
The Universal Declaration of Human Rights and the International Covenant on Economic, Social and Cultural Rights provide for rights to health, work, education, and family—all of which are imperiled by extreme heat. Approximately 489,000 people died of heat-related causes each year between 2000 and 2019, with infants, children, the elderly, pregnant women, outdoor workers, homeless individuals, and those with preexisting conditions being especially vulnerable. Summer heatwave events can cause high acute mortality; upwards of 70,000 people died as a result of Europe’s 2022 summer heat. Moreover, heat waves lead to dangerous working conditions, increased occupational injuries, and school closures—the United Nations Secretary General’s office recently estimated that 118 million children’s schooling was impacted by extreme heat in April 2024 alone.
Legal authorities have acknowledged the links between heat and fundamental human rights. In a landmark 2024 case, the European Court of Human Rights affirmed that insufficient action by the Swiss government to mitigate the impacts of extreme heat violated a group of women’s human right to family life. While an important first step, much work remains to ensure communities already impacted by heat are made whole.
Turning scientific certainty into legal accountability
In lawsuits, causation is typically divided into two parts: general causation (whether greenhouse gas emissions caused the harm experienced by plaintiffs) and specific causation (whether the defendants’ specific emissions caused the harm). Climate change, however, is global, cumulative, and involves countless actors over decades—it’s no easy task to trace a hurricane or drought in a specific region back to a single company or set of emissions. This complexity has allowed powerful fossil fuel corporations to argue that the chain of causation is too diffuse, and that their specific emissions cannot be definitively tied to a particular loss.
In recent years, however, climate attribution science has evolved rapidly. Scientists can now assess, with increasing precision, how much more likely or more intense an extreme weather event became due to anthropogenic climate change, and even the proportion of that change attributable to emissions from Carbon Majors. There has not yet been a lawsuit in which a court has ordered payment for climate damages based on this multi-step chain of causation, but attributing extreme heat events to a particular group of emitters is increasingly supported by rigorous science. In a 2023 lawsuit against Exxon Mobil, an Oregon municipality cited several attribution science studies showing that climate change played a key role in causing a 2021 Pacific Northwest heatwave and the corresponding $50 million in costs to the county. In April 2025, scientists published a novel “end-to-end” attribution framework that uses peer-reviewed methods to draw quantitative links between Carbon Majors and specific harms resulting from heat. According to the publication detailing this framework, when it comes to litigating heat harms, science is “no longer an obstacle to the justiciability of climate liability claims.”
Extreme heat is not a future threat. It’s here, it’s deadly, and it’s growing worse. And it’s one of the most clearly attributable symptoms of a climate crisis driven by the use of fossil fuels. By centering extreme heat in loss and damage litigation, lawyers and communities can offer a compelling scientific bridge between emissions and harm, establishing a stronger foundation from which to seek justice for those affected by one of the most deadly impacts of historical emissions. In the fight for climate accountability, the rising temperature is not just a warning—it’s evidence.