For the first time, scientists have directly linked fossil fuel companies to the economic damages caused by extreme heat - and they’ve put a dollar figure on it. A new Nature study lays out a full "end-to-end" climate attribution framework that connects individual companies’ emissions to specific heat-driven losses around the world.

The numbers are staggering. Between 1991 and 2020, heatwaves intensified by fossil fuel emissions led to an estimated $28 trillion in global economic losses. Chevron alone is linked to $1.98 trillion of those losses, while Saudi Aramco tops the list with $2.05 trillion. ExxonMobil, BP, and Gazprom follow closely behind, each responsible for more than $1.4 trillion in heat-related damages.

These costs aren’t abstract - they’re grounded in GDP losses. The study modeled how emissions from 111 fossil fuel companies warmed the planet, then used economic data to calculate how extreme heat affected income growth in nearly every region on Earth. One of the key results: Chevron’s emissions raised global temperatures by 0.025 °C, contributing to hotter days and lost income, especially in tropical countries least responsible for the climate crisis.

The economic damage also isn’t distributed evenly. While companies like Chevron, ExxonMobil, BP, and Gazprom are headquartered in the U.S., UK, and Russia, the worst losses were felt in South America, Africa, and Southeast Asia, where annual per-capita GDP losses from extreme heat exceeded 1%. In contrast, the countries profiting from fossil fuels saw far milder costs.

To make these connections, the researchers simulated a counterfactual world in which each company's emissions were removed. They then compared this world to actual observed climate data to measure each company’s impact on warming, extreme heat (defined as the five hottest days per year), and resulting economic fallout. Their method, validated against IPCC data and peer-reviewed sources, produced results so robust that the 99% confidence intervals for the top five emitters exclude zero - meaning it's virtually certain they caused significant harm.

The study also broke down losses from four major heatwaves, showing how the top emitters worsened specific disasters:

• In the 2012 U.S. heatwave, Chevron’s emissions alone are linked to $28.8 billion in damages.
• In France’s 2003 heatwave, ExxonMobil added $3 billion to the economic toll.
• The 2010 Russian heatwave saw Gazprom linked to $6.6 billion in added losses.
• In India’s 1998 heatwave, the top five companies together raised peak heat by 0.08 °C, worsening economic conditions for millions.

While courts have long struggled with the challenge of proving direct causation in climate cases, this study removes a major barrier. For decades, fossil fuel companies argued it was impossible to link their emissions to specific climate disasters - but the new framework shows otherwise. It not only quantifies the damage but also identifies who caused it, opening the door for more precise and evidence-backed litigation. As more regions suffer the economic impacts of climate extremes, and as climate lawsuits rise globally, this science could help judges, juries, and lawmakers weigh responsibility with new clarity.