Climate change made the floods in southern Brazil twice as likely

The study finds that human-induced climate change, driven by the burning of fossil fuels, made the extreme rainfall events in Rio Grande do Sul more than twice as likely and increased their intensity by 6-9%. The El Niño Southern Oscillation also played a significant role, increasing the likelihood of such events by a factor of 2-5. The floods affected over 90% of the state, causing 169 deaths and displacing over 580,000 people, with impacts exacerbated by poverty, failing flood protection infrastructure in Porto Alegre, and inconsistent enforcement of environmental protection laws.

• Human-induced climate change resulting from the burning of fossil fuels increased the likelihood of both the 4-day and 10-day extreme rainfall events in Rio Grande do Sul by more than a factor of 2, and increased their intensity by 6-9%.
• The El Niño Southern Oscillation (ENSO) significantly contributed to the rainfall variability; compared to a neutral phase, the December-February El Niño increased the likelihood of the 10-day event by a factor of 2-3 and the 4-day event by a factor of 2-5.
• In a scenario of 2°C of global warming since pre-industrial times, the likelihood of these rainfall events would increase further by a factor of 1.3-2.7, with intensity increasing by approximately 4% compared to current levels.
• The 2024 floods impacted over 90% of Rio Grande do Sul, causing 169 deaths and displacing 581,638 people. Vulnerability was heightened by low income, affecting informal settlements, indigenous villages, and quilombola communities.
• Infrastructure failures and policy gaps worsened the disaster: Porto Alegre's flood protection system failed at 4.5m despite a 6m capacity, and Brazilian environmental laws protecting waterways are not consistently enforced, leading to construction on flood-prone land.

APA

World Weather Attribution (2024). Climate change made the floods in southern Brazil twice as likely. https://www.worldweatherattribution.org/climate-change-made-the-floods-in-southern-brazil-twice-as-likely/

Chicago

World Weather Attribution. Climate change made the floods in southern Brazil twice as likely. 2024. https://www.worldweatherattribution.org/climate-change-made-the-floods-in-southern-brazil-twice-as-likely/.

Wikipedia

{{cite report |author=World Weather Attribution |title=Climate change made the floods in southern Brazil twice as likely |date=3 June 2024 |url=https://www.worldweatherattribution.org/climate-change-made-the-floods-in-southern-brazil-twice-as-likely/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldweatherattribution2024climate, author = {{World Weather Attribution}}, title = {{Climate change made the floods in southern Brazil twice as likely}}, institution = {World Weather Attribution}, year = {2024}, month = jun, url = {https://www.worldweatherattribution.org/climate-change-made-the-floods-in-southern-brazil-twice-as-likely/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }