Human-caused climate change made the record heat wave in northern Argentina and Paraguay in early December about 60 times more likely, according to a rapid attribution analysis by an international team of leading climate scientists as part of the World Weather Attribution group.
Beginning in mid-November 2022, large northern regions of Argentina and neighboring countries experienced unusually high temperatures. During a second heat wave in early December, temperatures exceeded 40°C at 24 locations, four of them above 45°C. The Rivadavia station, located near the border with Bolivia and Paraguay, recorded a maximum temperature of 46 °C on December 7, making the region one of the hottest in the world on that day. During the heat wave, nine locations in northern Argentina recorded their highest December maximum temperature since at least 1961.
The area is also experiencing a prolonged drought that began in 2019 and has worsened ever since. Drought and heat reinforce each other and exacerbate impacts on agriculture. Harvests are expected to be the worst in seven years, with heavy economic losses for farmers and the Treasury, as Argentina is South America’s largest wheat exporter. As a major player in the global wheat market, this could mean further increases in world food prices. World Weather Attribution scientists will conduct additional study of the drought in the coming months.
Around the world, climate change has made heat waves more common, longer, and hotter. To quantify the effect of climate change on high temperatures in northern Argentina and Paraguay, the scientists analyzed weather data and computer model simulations to compare the climate as it is today, after about 1.2°C of global warming since late 19th century, following peer-reviewed methods. This is the first study the group has conducted on an extreme weather event in either country.
The analysis focused on the daily maximum temperature for the hottest one-week period, from December 4 to 10, 2022. It found that the frequency and magnitude of such events has increased due to human-caused climate change.
The results showed that human-caused climate change has made an event like a heat wave about 60 times more likely to occur and can now be expected about once every 20 years, with a 5% chance that it will occur. happen every year. Without the effects of human greenhouse gas emissions, this would have been an extremely unusual event. A heat wave that occurs as often as this is now around 1.4°C hotter due to climate change.
“There is growing concern in Argentina and South America about heat waves, which have become more frequent and severe in recent decades. These recent events are a clear example of this. And unless carbon emissions are reduced , climate change will continue to favor the appearance of record temperatures in late spring and early summer, at a time of year when people are not prepared to deal with extreme heat,” says Juan Rivera, a scientist at the Argentine Institute of Snow Research, Glaciology and Environmental Sciences (IANIGLA).