DUBAI – Greenhouse gas emissions made recent deadly flooding in the United Arab Emirates (UAE) and Oman anywhere from 10 per cent to 40 per cent more intense than it would have been in the pre-industrial era, according to a rapid analysis of the event by the World Weather Attribution (WWA) research initiative.

Major storms come irregularly to the south-eastern Arabian Peninsula. When they do, they tend to land under conditions of El Niño, the occasional warming of the eastern equatorial Pacific that plays havoc with weather around the world. (An El Niño has been in place since June.)

Despite accurate forecasting and public alerts in Oman and the UAE, infrastructure there is poorly suited to deal with increasingly intense flash floods: Eighty per cent of Omanis and 85 per cent of Emiratis live on low-lying, flood-prone ground, according to WWA, and 90 per cent of the UAE’s infrastructure is at risk from rising sea level and extreme weather. 

“If there would not have been an El Niño year, it would have not rained in this way. But at the same time, if it would not be for climate change, it would not have rained so heavily as it did now,” said Dr Friederike Otto, a senior lecturer in climate science at Imperial College London and a WWA researcher.

“Both were important factors for driving this event.”

Worldwide, extreme rain has increased in intensity and frequency with the rising temperature, the United Nations Intergovernmental Panel on Climate Change has found.

Part of the reason has to do with a simply stated fact about air and water discovered in the mid-19th century: For every 1 deg C increase, air can hold about 7 per cent more water. Global and regional findings about rising risks underlie the WWA scientists’ conclusions about the local effects.

But making similar statements about a smaller patch of Earth can be more difficult, because of shorter data records or local limitations on sharing weather station data with researchers.

The scientists said the storm could be a 1-in-25-year event, but could not say how much climate change is worsening El Niño-juiced storms.

A different team of scientists in January found that by mid-century, annual rain in the UAE may rise by up to 30 per cent, with an increase in days seeing 10mm or more of rain. More than 250mm fell on Dubai on April 14 and April 15. 

The rarity and irregularity of massive deluges in the region left the researchers with a small data set to work with, and consequently high statistical uncertainty.

They concluded that climate change worsened the storm based on what the short meteorological record does offer them, combined with regional and global trends, the fact of warmer air holding more water, and that climate-driven circulation changes can worsen such storms.

There are “no other known explanations for the increasing rainfall in the region”, they wrote.

In addition to their climate-science conclusions, the WWA researchers analysed vulnerabilities that exacerbate hazardous conditions and address how Emirati and Omani officials might adapt to future floods.

The flooding killed two dozen people, most of whom were on the move – many had to leave cars on roads – suggesting that warnings failed to reach everyone.

For urban planners, the floods should highlight how the built environment can exacerbate flooding, namely lots of impermeable surfaces and little or no stormwater infrastructure. 

“There was an early warning system being disseminated through the media and news. But the problem is that people do not care about this early warning system,” said Professor Mansour Almazroui, a researcher at the Centre of Excellence for Climate Change Research at King Abdulaziz University, in Jeddah, Saudi Arabia.

Governments of the region could work with the media to communicate potential danger more thoroughly and effectively, he said, and with each other to improve the quality of weather data available for public consumption.

The intense rainfall drew attention to the UAE’s long-running cloud-seeding programme.

The WWA scientists wrote that even if seeding had happened, it would not have changed the amount of water vapour in the air, which was the major factor in the rainfall.

“Hence,” they wrote, “we can conclude that cloud seeding had no significant influence in the event.” BLOOMBERG