El Niño-related warming in the tropical Pacific and warming in parts of the tropical Atlantic could signal extreme heat in areas of the Amazon as much as seven months in advance, according to a new study.
The research, published in the journal Earth’s Future, examined how major patterns of natural climate variability affect temperature and rainfall extremes across the Amazon Basin. The Australian climate research centre ARC Centre published the findings on Tuesday.
Researchers found that extreme heat was more likely after unusually warm ocean conditions associated with El Niño in the tropical Pacific and warming in parts of the tropical Atlantic.
The clearest long-range signal was for March to May, when extreme heat in the Amazon was associated with ocean conditions observed up to seven months earlier.
“It is quite surprising that heat extremes are linked to conditions in the Pacific and tropical Atlantic Oceans observed up to seven months in advance,” said study co-author Andrea Taschetto, an associate professor at UNSW.
The team analyzed monthly climate data from 1950 to 2023 across six Amazon regions and used machine learning to study compound hot-and-dry events.
Such events can raise wildfire risks, damage ecosystems and threaten human health, food security and water supplies.
However, the researchers said the seven-month relationship applies to extreme heat and does not provide reliable forecasts of combined heat and drought that far in advance. The predictability of compound events varied considerably by season and region, with useful signals generally limited to shorter periods.