A powerful rainstorm that wreaked havoc on the desert nation of the United Arab Emirates last week was likely made more intense because of climate change, a team of international scientists has found.
The World Weather Attribution (WWA) group, composed of researchers from around the globe, said rain storms like the one that struck last Monday have become 10 to 40 per cent more intense because of human-induced climate change.
The storm was also a product of El Niño, a natural, cyclical warming in the Pacific Ocean that leads to more rain in the region, the researchers said.
"Both El Niño and human-caused climate change appear to be influencing heavy rainfall in the UAE and Oman," said Friederike Otto, a climate scientist at Imperial College London, and one of the authors of the study.
"While we can't stop El Niño, we can stop climate change."
The WWA, founded in 2015, studies extreme weather events, such as droughts, floods and heat waves in an attempt to determine the role played by climate change. The study was not published in an academic journal, but relies on peer-reviewed techniques, the researchers said.
Across the UAE and Oman, flooding damaged buildings and cars, and resulted in power outages and school closures, the study said.
Flash flooding caused 19 deaths in Oman, including 10 children who died when a school bus was swept away. In the UAE, four people died in cars in floodwaters.
More than 1,000 flights were cancelled with several days of delays after a runway was flooded at Dubai International Airport, one of the world's busiest. The rain also affected Bahrain, Qatar and Saudi Arabia.
Unprecedented rainfall
In Dubai, more than 14 centimeters of rain fell over 24 hours between April 14 and 15, which is equivalent to a year and a half of rainfall in the desert city, and the heaviest to fall in the UAE since records began in 1949.
In this case, the researchers were not able to draw as direct a connection to climate change as they have in previous studies.
As part of its calculations, the WWA usually uses computer modelling to compare a weather event to one in a simulated world without climate change.
In this case, there weren't enough publicly available data points to make such a comparison.
But the researchers were able to study past observations, the other main tool they use, to determine the 10 to 40 per cent increase in rainfall amounts.
Despite the limitations of the analysis, Otto said at a Thursday news conference it's clear that in future, during El Niño years, "it will rain more than it would have if we were not continuing to burn fossil fuels and warm the climate."
The report ruled out speculation that cloud seeding had played a role in the heavy rainfall.
The researchers said that given the size of the storm system, the rainfall would have fallen regardless of whether operations had been carried out — and that a storm had been expected for days.
"This type of rainfall never comes from cloud seeding," said Mansour Almazroui of the Center of Excellence for Climate Change Research at King Abdulaziz University in Saudi Arabia, one of the study's co-authors.
Adaptation in the desert
Nathan Gillett, an expert in attribution science and research scientist with Environment and Climate Change Canada, who was not involved in the WWA study, said the link between climate change and the event is not as well defined as it has been in other attribution studies, given the data limitations.
"The direct modelling of this event is less conclusive," he said. More broadly, though, Gillett said research suggests climate change is leading to increasingly extreme rainfall events in the region.
Almazroui said the findings underscore the need for improved adaptation to heavy rainfall in the region, and for an effective alert system.
Roop Singh, a specialist at the Red Cross Red Crescent Climate Centre, said in this case the rainfall was well forecast and dangerous flooding was expected; the majority of fatalities occurred inside vehicles.
"It is critical that future flooding preparations focus on early warning to ensure people aren't in harm's way when extreme rainfall hits the Arabian Peninsula," Singh said.
