Close up of dandelion seeds

May 3, 2024, by Brigitte Nerlich

Seeding clouds – seeding doubts

In 2009, two things happened in climate change discussions that at first glance seem to be quite unconnected. Firstly, the Royal Society released a seminal report on ‘geoengineering’—the deliberate alteration or creation of weather and climate conditions (which is generally considered unwise). Secondly, the ‘climategate‘ controversy emerged, portraying climate scientists as clandestinely tampering with or fabricating data. While the Royal Society report acknowledged the seriousness of anthropogenic climate change, the climategate incident fostered scepticism, even suggesting it was a hoax.

Fast forward fifteen years, and these divergent trends in climate discourse have intersected in the context of discussions about cloud seeding, a method of weather modification sometimes categorised as a form of geoengineering. Some now speculate that this practice shows that climate scientists not only manipulate data but also the climate itself. How did this come about?

Dubai floods

On 16 April 2024 heavy rains caused floods in the United Arab Emirates or UAE. We all saw the effects especially in Dubai, where the airport became a lake. To be more precise: “more than 142 mm (5.6 inches) of rain soaked Dubai itself, around as much as normally falls in a year-and-a-half at Dubai International Airport, where the annual average is 97 mm and the average for April is only around 8 mm.” This was an extreme weather event, all the more remarkable as it happened in a desert region.

Now, a desert region needs rain sometimes. So, as reported in New Scientist, the “UAE has maintained one of the world’s most extensive cloud seeding programmes since 2002. In an effort to increase freshwater resources in the arid region, planes regularly fly cloud-seeding missions.”

Seeding clouds

Cloud-seeding has been used since at least the mid-twentieth century to modify weather conditions, especially for drought management. It is regarded by some as a form of geoengineering or climate engineering, although some argue that, strictly speaking it is too localised to be categorised as such.

It “usually involves spreading fine particles into individual developing clouds that wouldn’t normally lead to rain. Small planes burning salt flares fly through the developing clouds, hoping that the tiny particles produced will act as cloud condensation nuclei and trigger the formation of water droplets and eventually rain.”

There are a lot of uncertainties surrounding the efficacy and impacts of cloud seeding. A New Scientist article quotes Andrew Dessler at Texas A&M University as noting that “Many of the claims of successful cloud seeding are wrong, scientifically flawed or actual fraud … This makes most atmospheric scientists very sceptical of cloud seeding.” What about those normally sceptical of climate change? Here things are different.

Seeding doubts

Shortly after the floods in Dubai, stories emerged that this extreme weather event was caused by cloud seeding. Some people sceptical about the causes, impact or severity of anthropogenic climate change began to speculate on Twitter/X whether cloud seeding ‘caused’ the extreme weather event in the region; indeed some began to wonder whether it demonstrated that climate change as a whole was the result of scientists manipulating not only data but the climate itself.

Judith Curry, a climatologist, tweeted: “Torrential rains in Dubai – unintended consequence of cloud seeding?” She later called those doubting that cloud seeding could bring about such an extreme weather event ‘cloud seeding deniers’. This new derogatory term was then also applied to people who regard anthropogenic climate change as real and not as a hoax.

Going beyond the Twittersphere, there were even stories in the mainstream media that the University of Reading was involved in cloud seeding in Dubai, a story reported by the Daily Telegraph under the headline “Reading University denies responsibility for catastrophic Dubai floods”.

Dispelling doubts

There were some quick push-backs against such emerging talking-points amongst those sceptical of climate change and of links between climate change and extreme weather events.

Doug McNeal, a climate scientist and statistician at the Met Office Hadley Centre, tweeted in a reply to Curry’s tweet: “This will be the new climate denial line – it wasn’t climate change it was cloud seeding. Question mark to provide cover. Plays into anti-government/conspiracy tropes.”

The University of Reading responded to the accusations in the Daily Telegraph by tweeting

“Sorry to rain on your parade @Telegraph

  1. We haven’t issued a denial
  2. We aren’t cloud seeding in UAE
  3. Our weather and climate scientists are providing evidence-based comments to explain what happened
  4. Read more from them at https://rdg.ac/49GVsW3
  5. Jog on”

The fifth point caused some hilarity.

Using more serious language, Professor Maarten Ambaum, a meteorologist at the University of Reading who has studied rainfall patterns in the Gulf region, said: “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”.

The Royal Meteorological Society pointed out that “in this case, the clouds were part of a large weather system advancing across the region, and already predicted to produce substantial amounts of rain across a wide area. Any possible effect from cloud seeding would be tiny in comparison. So the tales of cloud seeding simply don’t make sense, and are a distraction from the most likely guilty party — climate change.”

This echoed what Doug McNeal had tweeted. Other expert, such as Michael Mann and Friederike Otto, made similar points. On 22 April the Illawarra Mercury (NSW, Australia) reported on these discussions in an article aptly titled “Seeds of doubt about Dubai floods”.

Back in the UAE “Dr. Diana Francis, Senior Research Scientist, and Head of the Environmental and Geophysical Sciences (ENGEOS) Lab at Khalifa University [Abu Dhabi] made it very clear “that cloud seeding did not cause or contribute to the exceptional rainfall event, as the scale of the event is quite large and has impacted several countries in the region. Additionally, the event was forecasted at least 5 days in advance, and in those forecasts, cloud seeding is not accounted for. Furthermore, when such severe events are forecasted, cloud seeding is not conducted because it is too risky for the pilots to fly inside those convective clouds.”

And finally: “cloud seeding aims to enhance rainfall by helping water vapour to condense in existing clouds. It cannot in any way create clouds or water vapour itself, these must be present in order to perform seeding. During this event, all the conditions were met to produce large amounts of rain without the need for seeding.”

So, it is rather hard to attribute extreme weather events to human-induced rain, but what about attributing extreme weather events to human-induced climate change?

Straight after the floods, researchers “from Saudi Arabia, Pakistan, Switzerland, the Netherlands, Sweden, the United States, Canada, France and the United Kingdom collaborated to assess to what extent human-induced climate change altered the likelihood and intensity of the weather conditions at the time of the most impactful floods”.

They published a World Weather Attribution report and their results seem to indicate (but there are some uncertainties) that, as Friederike Otto tweeted, the “Deadly floods in hyper-arid Dubai & Oman [were] made more intense by climate change, El Nino and rapid urbanisation”. The report also concludes more decisively that, according to the last sentence of the report: “cloud seeding had no significant influence in the event”.

Effects of clouds; effects of doubts

We thus have two opposing climate change discourses. One discourse centres around the claim that cloud seeding is used to not only to modify clouds but the climate itself. The other discourse centres around the claim that cloud seeding only modifies clouds but not the climate itself. Why is that important? Because which way you chose to argue might have legal and political consequences.

In his book on geoengineering Jack Stilgoe wrote about the 1952 Lynmouth floods in the UK and points out that some people attributed the devastating floods to cloud seeding experiments conducted by the Met Office and the Ministry of defence.

In 1976 an article entitled “Whose rain?” appeared in Forbes and reported that “Citizens have brought suits alleging cloudseeding has caused floods and damages. Farmers have waged battles over the right to rain” (1 May).

More disturbingly, in 2018 “a senior Iranian official accused Iran’s foreign enemies, including Israel, of modifying the weather in the country in order to create drought” – indeed of “stealing clouds”, and so on.

After the Dubai floods the Daily Mail published an article warning about ‘weather wars’ and so did other news outlets.

Attributing droughts or floods to cloud seeding has serious consequences and so has not attributing droughts or floods to climate change. The former may lead to local litigation and weather wars; the latter to distracting attention away from global climate mitigation efforts.

Image: Tom Gill: Dandelion seeds, Flickr

Posted in Climate Change