Fatal storms in the United Arab Emirates (UAE), where at least one person was killed and Oman, where at least 20 more died, trapped residents in buildings and places of work, washed away roads, took out power supplies and caused widespread travel chaos and congestion, including at one of the world’s busiest airports, Dubai.
A year’s worth of rain
One of the more unusual results of the storm though, has been the circulation of conspiracy theories about its origin. Rumours are rife that the storm, which brought a year’s worth of rain (254 millimetres or 10 inches), in just 24 hours, beating all records going back to 1949, was triggered by the UAE’s practice of cloud-seeding.
The Arabian Peninsula has a dry desert climate and temperatures can reach more than 50 degrees Celsius in the summer months. However, the usual lack of rain means the region copes badly when the rains do come, they can overwhelm drainage and sewer systems and wash away roads.
Geo-engineering and cloud-seeding
To mitigate the challenges of their dry climate, the UAE has become a world leader in geo-engineering, particularly cloud-seeding – a practice which sees substances such as carbon dioxide (in the form of dry ice) and silver iodide injected into clouds to encourage the build up of condensation which is then released as rainfall. Cloud seeding, therefore, requires the existence of clouds already before it can work.
April is not an unusual month for rain in the UAE (and elsewhere) due to seasonal changes in atmospheric pressure. Last week, a combination of low pressure and cooler temperatures high in the atmosphere and low pressure and warmer conditions nearer the Earth’s surface effectively trapped and squeezed the air, according to the UAE’s National Centre of Meteorology. But the body, which is involved in deciding on the timing of cloud-seeding operations, denied that any seeding had occurred in the clouds building prior to last week’s storms.
Why were the storms so unusually intense then?
The answer, climate scientists say, is global warming. “Rainfall from thunderstorms, like the ones seen in UAE in recent days, sees a particular strong increase with warming,” Dim Coumou, a climate professor at Amsterdam’s Vrije Universiteit, told Reuters, adding it happens because “convection, which is the strong updraft in thunderstorms, strengthens in a warmer world.”
Worse, global warming has made the seas around Dubai “extraordinarily” warm, said Mark Howden, Director of Australia’s National University Institute for Climate, Energy & Disaster Solutions. Meaning their evaporation rate is increased, just as the warmer air above is ripe for holding more moisture “allowing bigger dumps of rainfall such as what we have just seen in Dubai,” he said.
