Studies have shown that South America is facing an increased risk of heat waves, droughts and fires.

In parts of South America, the number of extremely hot, dry and fire-prone days per year has tripled since 1970.

South America is warming at a similar rate to the global average. However, some parts of the subcontinent are at increased risk of multiple simultaneous extreme weather events. These compound extreme weather events could have amplified impacts on ecosystems, economies, and human health.

Raul Cordero and his colleagues calculated the number of days per year that experienced extreme weather that was simultaneously hot, dry and flammable for each roughly 30-by-30-kilometer grid cell in South America between 1971 and 2022. Their results are published in the journal Communications Earth & Environment.

Extremes for each condition were calculated from daily maximum temperature records, 30-day precipitation averages, and daily fire weather index records. The authors found that the frequency of these co-occurring extremes is increasing across the continent.

The increases were particularly strong near the Venezuela-Colombia border, in the northern Amazon, and in the northern Rio de la Plata basin in central South America, from fewer than 20 to as many as 70 days per year. The authors also found that the year-to-year variability of these co-occurrences has increased over the past 50 years.

Furthermore, the authors found that the regional likelihood of the combined conditions was influenced by the El Niño-Southern Oscillation: warmer El Niño periods increased fire risk in the northern Amazon region, while cooler La Niña periods increased fire risk in central South America.

The authors warn that both increased fire activity and extreme dryness are public health hazards and could cause further warming by releasing black carbon into the atmosphere.

They also highlight that these extreme events disproportionately affect vulnerable rural and Indigenous peoples, and recommend that policymakers in the region place greater emphasis on mitigating these extreme events.