Libya Storm’s Severity Caused in Part by Climate Change, Scientists Say

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By Chao Deng and Eric Niiler Published On: September 19, 2023 11:09 am ET

Human-caused climate change caused a 50% increase in heavy rainfall over the Mediterranean that led two dams in Libya to collapse, killing thousands of people and creating a massive humanitarian disaster, according to a group of international climate change scientists.

The scientists from the World Weather Attribution group said greenhouse-gas emissions made heavy rainfall 50 times more likely in Libya when Storm Daniel hit the Mediterranean early this month. The impact of climate change combined with Libya’s weak infrastructure and history of conflict make the impact of the storm even more deadly. The report suggests that underdeveloped countries like Libya are at greater risk of harmful impacts due to climate change.

“This devastating disaster shows how climate change-fueled extreme weather events are combining with human factors to create even bigger impacts,” said Julie Arrighi, director at the Red Cross Red Crescent Climate Centre, who reviewed the study.

Still, they termed the event in Libya “extremely unusual” and said it would only be expected to occur once in 300 to 600 years.

The report wasn’t peer reviewed in a journal, but used peer-reviewed methods. The WWA researchers, who were from universities and research institutes in Europe and the U.S., warned that their study carried large mathematical uncertainty but that increased atmospheric temperatures generally lead to heavier rainfall.

The storm in Libya began early this month in Spain, when a low-pressure system that scientists named Storm Daniel formed in the eastern Mediterranean Sea. It brought over 10 days of rain to Greece, Bulgaria and Libya. More than 30 people were killed in Bulgaria, Spain, Turkey and Greece, before the storm wreaked havoc in the eastern Libyan city of Derna, where rainwater filled two dams and triggered their collapse last week.

The gush of water and mud from the dams damaged most of central and downtown Derna, sweeping away or forcing the evacuation of tens of thousands of people from their homes. While Libyan residents and officials blame the mounting death toll on the failed dams and their lack of upkeep by the government, they also say that the country overlooked risks, having never experienced such a huge storm. Relief workers have been overwhelmed by the magnitude of the crisis, with residents of Derna still calling for food, water and medicine.

The valley above Derna has flooded multiple times over the past century and twice since the dams were built, according to Sameh Kantoush, associate professor at Kyoto University’s Water Resources Research Center in Japan, who studies natural disasters throughout the Mediterranean basin but wasn’t involved in the study. Kantoush said the reservoirs behind the dams filled with sediment over time, reducing the capacity to retain floodwaters, and unleashing a torrent of powerful mud when they failed.

“Our climate is changing, and our structures are static,” Kantoush said.

The authors of the study said that the destruction in Libya was much greater because of construction in flood-prone areas, deforestation and yearslong internal conflict.

“I would say in general we’re not resilient to weather extremes in any country,” says Mari Tye, a project scientist at National Center for Atmospheric Research who wasn’t part of the study. “Unfortunately we see financial consequences higher in developed nations and human consequences higher in least developed nations.”

The results of the study speak to what scientists believe is a global phenomenon of climate change making extreme weather—from droughts to hurricanes and flash floods—more likely.

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Volunteers carry victims ofthe flooding to bury them at a cemetery in Derna, Libya. PHOTO: ZOHRA
BENSEMRA/REUTERS

 

 

 

 

 

 

 

 

Warmer conditions directly contribute to larger storms. Since 1970, the intensity of rainfall has increased 10% to 20% in the U.S. and elsewhere around the world.

The Mediterranean Sea, which is smaller and comparatively shallower than the Atlantic and Pacific Oceans, is warming up 20% faster than the global average. Global oceans in August were the warmest they have been in recorded history going back to the 1940s.

According to the World Meteorological Organization, sea surface temperatures above 78.8 degrees Fahrenheit can enhance and fuel storm systems after they develop. Near the coast of Libya, sea surface temperatures were above 81.5 degrees Fahrenheit.

Libya’s National Meteorological Center reported that the storm reached a peak on Sept. 10 with winds of 43 miles to 50 miles an hour. It dumped 16 inches of water in 24 hours at one Libyan weather station in Al Bayda, a city roughly 60 miles from Derna, setting a new rainfall record for the country.

The center issued an early warning for the storm 72 hours before it hit, but authorities didn’t anticipate the collapse of the dams. According to the World Meteorological Center, Libya’s meteorological center is short staffed and stuck with poor technological systems.

Shlomit Paz, a climate scientist at the University of Haifa in Israel who wasn’t involved in the study, said that most Mediterranean and North African nations haven’t taken steps to mitigate or adapt to climate warming, and less developed countries such as Libya that lack modern infrastructure and emergency response capabilities will continue to feel the effects of extreme weather events such as Storm Daniel.

“We don’t see rainfall in September in the Mediterranean, it is very rare,” Paz said. “But we have to realize that the rainfall patterns are changing and that we have to be much better prepared.”

Write to Chao Deng at chao.deng@wsj.com and Eric Niiler at eric.niiler@wsj.com