Climate change makes extreme wildfire conditions in Chile and Argentina up to 3x more likely

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Human-caused climate change increased the odds of the weather patterns that helped drive deadly wildfires in parts of Chile and Argentina’s Patagonia, according to a scientific assessment released Feb. 11. The analysis, led by World Weather Attribution, said warming made the extreme conditions that led to widespread burning up to three times more likely than they would have been without global warming.

In Chile, the researchers said the hot, dry and gusty weather that fed the fires was made around 200% more likely by human-made greenhouse gas emissions. They said the probability of similarly high fire-risk conditions would grow as the world continues to emit heat-trapping gases.

World Weather Attribution also attributed higher risk in southern Argentina to greenhouse-gas-driven changes in climate. The group said the high-fire-risk conditions there were made about 150% more likely, as wildfires moved through native forests and into areas that include Los Alerces National Park, a UNESCO World Heritage site.

The Chilean wildfires tore through the Biobio and Ñuble regions in mid-January, killing 23 people and destroying more than 1,000 houses and other structures, according to the assessment. The report said the fires were ignited by human activity, whether arson or negligence.

In southern Argentina, the fires began when lightning sparked blazes that later forced evacuations for thousands of tourists and residents, the assessment said. The wildfires burned through more than 45,000 hectares (174 square miles) of native forest, including extensive areas in and around Los Alerces National Park.

Clair Barnes, a research associate with World Weather Attribution, told reporters that the increased risk is linked to human-caused warming. She said the research team was “confident in saying that the main driver of this increased fire risk is human-caused warming,” and added that those trends are projected to continue “as long as we continue to burn fossil fuels.”

Carolina Vera, a professor of climate sciences at the University of Buenos Aires who was not affiliated with World Weather Attribution, said the findings align with earlier work on how global warming affects wildfires in Argentina. She said the fire case was one “in which the influence of anthropogenic climate change dominates over other factors,” describing how climate change affects wildfire-prone native forests in Chubut province.

Other outside scientists said the results fit established climate-model expectations, even as the underlying attribution report has not yet gone through peer review or publication in a scientific journal. Dominique Bachelet of Oregon State University said climate modelers have simulated increased fire danger for more than two decades, citing how warming deepens droughts, alters prevailing wind patterns and disrupts the timing and length of seasons.

The assessment also described non-climate factors that help disasters spread and persist. It said record droughts and scorching temperatures created wildfire-friendly conditions in both Chile and Argentina, and that certain land cover choices, including single-species plantations of highly flammable trees such as pines, can help fires move more easily. The report said invasive species have replaced native, more fire-resistant ecosystems in the region, turning shrubs, brush and grass into added fuel.

On government response, the researchers said resources and policies affected how prepared countries were for the fires. The report said Chile increased its wildfire-fighting budget by 110% over the previous four years under President Gabriel Boric, and that it used the added funding for forecasting and equipment, while researchers said Argentina’s response was constrained by austerity measures under President Javier Milei, including budget cuts to firefighting crews and deregulation tied to tourism in Patagonia’s national parks.

In Argentina, researchers and people involved in disaster relief described firefighting limitations and planning shortfalls, and the assessment said Milei has denied any link between climate change and human activity. Juan Antonio Rivera, an author of the study from Argentina’s National Scientific and Technical Research Council, said inadequate attention to climate change and its human drivers worsens such events, adding that the situation was “still not under control.”