Dubai (Agencies): Dubai, a city on the coast of the United Arab Emirates (UAE), known for its arid climate, has been hit by record floods over the past 24 hours. This unusual weather event has led to speculation about the role of cloud seeding.
Typically, Dubai receives less than 100mm (3.9in) of rainfall annually. However, it does experience occasional extreme downpours. In the city of Al-Ain, just over 100km (62 miles) from Dubai, about 256mm (10in) of rain was recorded in just 24 hours.
The main cause of this extreme rainfall was a “cut off” low pressure weather system, which drew in warm, moist air and blocked other weather systems from coming through. “This part of the world is characterised by long periods without rain and then irregular, heavy rainfall, but even so, this was a very rare rainfall event,” explains Prof Maarten Ambaum, a meteorologist at the University of Reading.
- Climate Change and Rainfall:
While it is not yet possible to quantify exactly how much of a role climate change played in this event, the record rainfall is consistent with changing climate patterns. Warmer air can hold more moisture – about 7% extra for every degree Celsius – which can increase the intensity of rain. “The intensity of the rain was record breaking, but this is consistent with a warming climate, with more moisture available to fuel storms and make heavy rainfall events and associated flooding progressively more potent,” explains Richard Allan, professor in climate science at the University of Reading.
A recent study suggested that annual rainfall could increase by up to about 30% across much of the UAE by the end of the century as the world continues to warm. “If humans continue to burn oil, gas and coal, the climate will continue to warm, rainfall will continue to get heavier, and people will continue to lose their lives in floods,” says Dr Friederike Otto, senior lecturer in climate science at Imperial College London.
- The Role of Cloud Seeding:
Cloud seeding, a technique that involves manipulating existing clouds to produce more rain, has been used in the UAE in recent years to address water shortages. This process involves using aircraft to drop small particles (like silver iodide) into clouds, allowing water vapour to condense more easily and turn into rain.
In the aftermath of the floods, some social media users were quick to attribute the extreme weather solely to recent cloud seeding operations in the country. However, experts say that at best, cloud seeding would have had a minor effect on the storm and that focusing on it is “misleading”. “Even if cloud seeding did encourage clouds around Dubai to drop water, the atmosphere would have likely been carrying more water to form clouds in the first place, because of climate change”, says Dr Otto.
Cloud seeding is generally deployed when conditions of wind, moisture and dust are insufficient to lead to rain. In the last week, forecasters had warned of a high flooding risk across the Gulf. “When such intense and large scale systems are forecasted, cloud seeding – which is a costly process – is not performed because [there is] no need to seed such strong systems of regional scale,” says Prof Diana Francis, head of the Environmental and Geophysical Sciences at Khalifa University.