The record drought that has affected large parts of South America for the past three years is being driven by the La Ni帽a weather system and exacerbated by climate change, an international group of climate scientists has determined.
Historically dry and hot weather in areas of Argentina, Chile, Brazil, Paraguay and Uruguay has forced countries to ration water and has devastated harvests, contributing to rising food prices globally.
Chile has seen giant reservoirs and is experiencing the deadliest wildfires in its history, while Argentina 鈥� which is seeing its lowest rainfall 鈥� is to lose $10 billion to $15 billion in export earnings this year, as wheat and soy exports drop by half.
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Climatologists have speculated that the extreme weather could be related to climate change, but at the University of Antioquia in Colombia and her colleagues have concluded that the La Ni帽a weather pattern, which is now in its third year, is the main cause of the extreme droughts.
The researchers used computer models to analyse past weather events in order to determine the likely causes of the low precipitation from October to December 2022.
La Ni帽a describes cool ocean temperatures in the eastern Pacific Ocean, which alter global atmospheric conditions and can cause extreme weather in much of the world.
In South America, the weather phenomenon usually makes countries in the north such as Colombia and Venezuela wetter, while those in the south such as Argentina and Uruguay get drier. A three-year La Ni帽a phase has only been recorded twice before: in 1973 to 1975 and in 1998 to 2001.
Although climate change isn鈥檛 driving the lack of rainfall, the 1.2掳C global temperature increase since the late 1800s is worsening its impact, the researchers concluded.
鈥淏oth natural variability and climate change are acting together, pushing in the same direction,鈥� says Arias.
Deforestation in the Amazon rainforest is also reducing water vapour in the atmosphere and could have an impact, she says.
Models suggest Earth鈥檚 weather system will switch from La Ni帽a into an El Ni帽o phase this year, which could bring relief to the region鈥檚 weather woes. 鈥淏ut you really cannot tell at this point,鈥� says Arias.
Climate models predict that rainfall in Chile in the second half of this century will be 30 per cent lower than the historical average, so the current crisis has lessons for the future, says at the Center for Climate and Resilience Research in Santiago, Chile.
鈥淲hat we are living today is a window into our future of water security, so on the one hand it鈥檚 a tremendous threat, but on the other it鈥檚 an opportunity to see all the things we need to do to manage climate change,鈥� says Christie.
Some politicians are calling for more action both to mitigate and prevent climate change, with elections taking place in Argentina and Paraguay this year.
Former Uruguayan president Jos茅 Mujica called for cattle ranchers to cross-breed cows with zebus 鈥� a subspecies of domestic cow originating in South Asia 鈥� to make them more resistant to heat, while Chilean president Gabriel Boric to 鈥渂uild back differently鈥� in the wake of forest fires. The Chilean government is proposing to guarantee people鈥檚 right to water in its
South America is ramping up its investment in such as green hydrogen, and experiencing a boom in innovation in the agricultural sector. According to research firm Radar Agtech, , up from 1124 in 2019.
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