Global warming didn’t necessarily lessen rainfall in the region, scientists found, but it probably exacerbated dry conditions.
(Bloomberg) — Argentina is experiencing its worst drought in 60 years. A new study finds that although climate change likely exacerbated the dry spell, it has not necessarily caused a decrease in rainfall.
Scientists with World Weather Attribution (WWA) studied the drought in central South America during the final three months of 2022. They found that rainfall over that period was lower than average but within expected natural variations in precipitation. As a result, it could not be directly linked to human-caused climate change.
Even so, the team did conclude that global warming likely contributed to dryness. Higher temperatures decrease the amount of available water, in part through a higher rate of evaporation, and probably worsened the effects of the drought.
As severe weather events become more common, scientists have sought to determine how exactly human actions are reshaping the planet. The WWA finding shows just how complicated that relationship can be.
“That’s one of the reasons why we do these attribution studies — to show what the realistic impacts of climate change are,” said Friederike Otto, a climate scientist at Imperial College London and co-leader of World Weather Attribution, a research collaboration that specializes in near real-time analysis of weather events.
“Not every bad thing that is happening now is because of climate change. It is really important to find out where climate change is a real game changer,” Otto said.
Researchers with WWA observed rainfall over a region including much of Argentina, Uruguay and a small portion of Brazil. The group found that the low levels of precipitation at the end of 2022 have a 5% chance of occurring in any given year.
As a result, the authors write, they “cannot be confident” that the lack of rain falls outside of natural variability in the region. The report acknowledges that La Niña, an atmospheric phenomenon that disrupts normal wind patterns, at least partially reduced the amount of rain.
Meanwhile, extreme heat stunted agricultural production in the region. Altogether, those high temperatures and dry conditions depleted crop yields and inflated global food prices.
Past studies from WWA have drawn more direct connections between observed weather events and human activities. A September analysis found that climate change intensified rainfall in Pakistan, contributing to deadly floods. Another report found that high temperatures on the North American Pacific coast in 2021 would have been “virtually impossible” without climate change.
The most recent study found a more complex relationship. According to Otto, that work is crucial.
“People weaponize the weather. If there’s a cold day, people say it’s not climate change, but of course that has nothing to do with physics or with how weather is,” Otto said. “What we are doing and why we are doing it is to show what are the realistic consequences of climate change, and how do they affect people now.”
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