EXTREME-WEATHER COSTSIn Years After El Niño, Global Economy Loses Trillions

In the years it strikes, the band of warm ocean water known as El Niño that spans from South America to Asia triggers far-reaching weather changes resulting in devastating floods, crop-killing droughts, plummeting fish populations, and an uptick in tropical diseases.

With El Niño projected to return this year, Dartmouthresearchers report in  Science that the financial toll of this recurring climate pattern can persist for several years after the event itself—and cost trillions in lost income worldwide.

The study is among the first to evaluate the long-term costs of El Niño and projects losses that far exceed those estimated by previous research.

El Niño is the warm phase of the El Niño-Southern Oscillation, the natural cycle of warm and cold temperatures in the tropical Pacific Ocean that includes La Niña, El Niño’s cooler counterpart. El Niño alters weather patterns worldwide and, in the United States, typically results in wetter, warmer winters for the West Coast and a milder hurricane season on the Atlantic seaboard.

Justin Mankin, an assistant professor of geography, and doctoral candidate Christopher Callahan spent two years examining global economic activity in the decades following the 1982-83 and 1997-98 El Niño events and found a “persistent signature” of slowed economic growth more than five years later.

The global economy bled $4.1 trillion and $5.7 trillion, respectively, in the half-decade after each of these events, most of it borne by the world’s poorest nations in the tropics.

Mankin and Callahan project that global economic losses for the 21st century will amount to $84 trillion as climate change potentially amplifies the frequency and strength of El Niño—even if current pledges by world leaders to reduce carbon emissions come to fruition. The researchers estimate that the El Niño predicted for 2023 alone could hold the global economy back by as much as $3 trillion by 2029.

The study addresses an ongoing debate about how quickly societies rebound from major climate events such as El Niño, said Callahan, who was lead author of the study.

“We can say with certainty that societies and economies absolutely do not just take a hit and recover,” said Callahan, adding that their data suggested a downturn after El Niño could last as long as 14 years, if not longer.