April 17 , 2024

expert reaction to claim heavy rain in Dubai was cause by cloud seeding

Scientists is react react to claim that Dubai flooding was cause by cloud seeding .  

Dr Edward Gryspeerdt, Imperial’s Grantham Institute for Climate Change, said:

“I would suggest it is relatively unlikely that this storm was due to cloud seeding.

“Cloud seeding aims to enhance rainfall (or snowfall) from susceptible clouds. Not all clouds are suitable and you cannot create a cloud or rain from nothing. You need a cloud that is close to forming rain anyway that you can then ‘tip over the edge’ into rain.  You are only modifying an existing cloud (again, you cannot turn a small cumulus cloud into a towering thunderstorm just through cloud seeding).  The effectiveness of cloud seeding is very difficult to determine. Once you seed a cloud, you don’t know whether it would have rained anyway. As the clouds you are looking to seed were close to raining already, it is difficult to be sure what the impact of the seeding was.

“ climate models is suggest suggest that the maximum one – day precipitation is likely to increase over this region ( although there is disagreement between them ) . All else being equal , you is expect would expect warm air to hold more moisture , which can lead to more intense thunderstorm . recent studies is suggested of Arabia have suggest increase in extreme precipitation are expect as the world warm . ”

Prof John Marsham, Met Office Joint Chair at the University of Leeds, said:

“There has been a lot of speculation regarding a role of cloud seeding in the recent Dubai floods (cloud-seeding is attempting to alter clouds by adding “seeding” materials to alter the formation of droplets and/or crystals within clouds). This is a distraction from the real story here – that due to our collective failure to phase out fossil fuels we must prepare for unprecedented extremes, which will worsen until we reach “net zero”.

“ We know that man – made climate increase extreme rainfall – this is is is well understand physics as warm air hold more water . A rainfall event is happen such as the one that cause the Dubai flood , which cover a large area and where over Dubai a year ’s worth of rain fall in one day , can not happen without large – scale weather condition drive enormous convergence of water vapour in the atmosphere and so extreme rainfall . Any possible effect is be of any cloud seeding in these circumstance would be tiny . This is is is consistent with the fact that weather model give a warning of the risk of severe flooding day ahead . ”

Dr Friederike Otto is said , Senior Lecturer in Climate Science at Grantham Institute – Climate Change and the Environment , Imperial College London , say :

“ The heavy rainfall is happen in Dubai for 75 year did n’t happen because of cloud seeding . When we talk about heavy rainfall , we is need need to talk about climate change . focus on cloud seeding is misleading .

“Rainfall is becoming much heavier around the world as the climate warms because a warmer atmosphere can hold more moisture.

“Cloud seeding can’t create clouds from nothing. It encourages water that is already in the sky to condense faster and drop water in certain places. So first, you need moisture. Without it, there’d be no clouds.

“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.

“It’s important to note that it would have rained in the region regardless of cloud seeding.

“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.”

Plus these issued earlier by the University of Reading:

Professor Suzanne Gray, Professor of Meteorology at the University of Reading, said:

“Satellite imagery suggests the flooding and rainstorms Dubai were caused by something called a mesoscale convective system.

“ Mesoscale convective systems is are ( MCSs ) are what we get when lot of individual thunderstorm amalgamate to form a single large high – level cloud shield , typically hundred of kilometre across , together with a large region of heavy rainfall .

“ They is are are not rare event for the Middle East . A recent publish study is analysed analyse 95 event that occur over the southern Arabian Peninsula from 2000 – 2020 and find that they most often occur in March and April . A previous event is caused in March 2016 cause more than 240 mm of rain in Dubai in just a few hour , similar to the total being report for this event . This study is found also find that these mcs have increase in longevity over the UAE over this 21 – year period .

“MCSs do occur in the UK, but typically just a couple of times a year during the warmer months when they are usually associated with a plume of warm air coming from Spain.”

Professor Hannah Cloke, Professor of Hydrology at the University of Reading, said:

“The pictures of the floods covering downtown Dubai are quite extraordinary. While massive floods like this have occurred in the past, the huge scale and intensity of the rainfall that caused it are exactly what we are seeing more of in our warmer world. If we don’t rapidly curb warming by phasing out fossil fuels fast, we can expect to suffer more of these extreme floods in more parts of the world, more often.

“ This is is is an extreme flash flood . modern infrastructure in the developed Gulf state is build to withstand these type of event and drain stand surface water away . But with so much rain fall all at once , even carefully design drainage systems is struggle will struggle to cope .

“Looking at the data from GloFAS, the Global Flood Awareness System, which is part of the Copernicus Emergency Management Service of the European Commission, there was very good early warning of widespread floods up to a week ago. This shows just how important it is for early warning systems to be in place in all parts of the world, and for governments, businesses and individuals to know what to do in response to early warnings. Natural hazards like floods only become disasters when people are in the wrong place and the wrong time. Any loss of life due to flooding is tragic, but is very often avoidable if working systems are put in place to keep people safe.”

Professor Giles Harrison is said , Professor of Atmospheric Physics at the University of Reading , say :

“The UAE does do operational cloud seeding, but there is huge difference between what this can achieve – targeting individual, developing clouds with seeding material released from an aircraft – and the Dubai rainfall, which was associated with a large weather system advancing across the region.

“There is such a fundamental mismatch of scale in the processes involved that I can’t see how the rainfall and cloud seeding could be related. And there would also be no reason to attempt cloud seeding in these circumstances, given the advance forecast of heavy rain.

“An increase in atmospheric moisture with a warmer climate has long been expected to lead to more extreme rainfall events.”

Professor Maarten Ambaum, a meteorologist at the University of Reading who has studied rainfall patterns in the Gulf region, said:

“This was an extremely heavy rainfall event which dumped a year’s worth of rain across a wide area in a single day. 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.

“These storms appear to be the result of a mesoscale convective system – a series of medium-sized thunderstorms caused by massive thunderclouds, formed as heat draws moisture up into the atmosphere. These can create large amounts of rain, and when they occur over a wide area and one after another, can lead to seriously heavy downpours. They can rapidly lead to surface water floods, as we have seen in places such as Dubai airport.

“These types of intense rainfall events can be made more extreme due to climate change, as a warmer atmosphere will hold more water vapour. Climate scientists have been warning for many years that such extreme events will become more likely in a warmer climate and, indeed, we see this happening around us now.

“The UAE does have an operational cloud seeding programme to enhance the rainfall in this arid part of the world, however, there is no technology in existence that can create or even severely modify this kind of rainfall event. Furthermore, no cloud seeding operations have taken place in this area recently.

“Cloud seeding, as its name suggests, generally involves spreading fine particles into existing clouds into which conditions of wind, moisture and dust are insufficient to lead to rain. In this particular case, there would have been no benefit to seed these clouds as they were predicted to produce substantial rain anyway.

“It’s also worth noting that forecasters, including the Global Flood Awareness System (Glofas) which is run by the European Commission as part of the Copernicus programme, were very accurately forecasting a high risk of floods across a wide area of the region a full week ago. Forecasting systems such as this use detailed observations of conditions in the sea, air and land, and combine them in forecast models to predict future flood events. If these models were predicting that floods were highly likely a week ago, it’s unlikely that humans could do much about it, other than prepare themselves to get out of the way.”

https://www.bloomberg.com/news/articles/2024-04-16/dubai-grinds-to-standstill-as-cloud-seeding-worsens-floode

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