The world's wealthiest 10% caused two thirds of global warming since 1990

The study assesses the contribution of the highest emitting groups within societies and finds that the top 1% of the wealthiest individuals globally contributed 26 times the global average to increases in monthly 1-in-100-year heat extremes globally and 17 times more to Amazon droughts.

The research sheds new light on the links between income-based emissions inequality and climate injustice, illustrating how the consumption and investments of wealthy individuals have had disproportionate impacts on extreme weather events. These impacts are especially severe in vulnerable tropical regions like the Amazon, Southeast Asia, and southern Africa -- all areas that have historically contributed the least to global emissions.

"Our study shows that extreme climate impacts are not just the result of abstract global emissions, instead we can directly link them to our lifestyle and investment choices, which in turn are linked to wealth," explains lead author Sarah Schöngart, an alumna of the 2024 Young Scientists Summer Program (YSSP), who is currently associated with ETH Zurich. "We found that wealthy emitters play a major role in driving climate extremes, which provides strong support for climate policies that target the reduction of their emissions."

Using a novel modeling framework that combined economic data and climate simulations, the researchers were able to trace emissions from different global income groups and assess their contributions to specific climate extremes. They found that emissions from the wealthiest 10% of individuals in the United States and China alone, each led to a two-to threefold increase in heat extremes across vulnerable regions.

"If everyone had emitted like the bottom 50% of the global population, the world would have seen minimal additional warming since 1990," says coauthor Carl-Friedrich Schleussner, who leads the Integrated Climate Impacts Research Group at IIASA. "Addressing this imbalance is crucial for fair and effective climate action."

The study also emphasizes the importance of emissions embedded in financial investments, rather than just personal consumption. The authors argue that targeting the financial flows and portfolios of high-income individuals could yield substantial climate benefits.

"This is not an academic discussion -- it's about the real impacts of the climate crisis today," adds Schleussner. "Climate action that doesn't address the outsize responsibilities of the wealthiest members of society, risks missing one of the most powerful levers we have to reduce future harm."

The authors suggest that their findings could motivate progressive policy instruments targeted at societal elites, noting that such policies can also foster social acceptance of climate action. Making rich individual polluters pay can also help to provide much needed support for adaptation and loss and damage in vulnerable countries. They conclude that rebalancing responsibility for climate action in line with actual emissions contributions is essential, not just to slow global warming, but to achieve a more just and resilient world.

The study is the result of work undertaken as part of Schöngart's YSSP project in 2024 for which she was awarded the IIASA Levien award.