by A reckless experiment in the Earth’s atmosphere caused a desert city to flood.
That was the case last week when more than a year’s worth of rain fell in one day on the Arabian Peninsula, one of the driest regions in the world. Abandoned cities such as Dubai in the United Arab Emirates (UAE) suffered floods that submerged motorways and airport runways. Across the UAE and Oman, 21 people lost their lives.
Heavy rain on Tuesday 16 April was initially blamed on “cloud seeding”: a method of triggering precipitation by injecting clouds with tiny particles that can hold moisture – these droplets then merge and multiply . As the waters receded, however, a more disturbing explanation emerged.
This round of The Conversation climate coverage comes from our weekly climate action newsletter. Every Wednesday, The Conversation’s environmental editor writes Imagine, a short email that goes a little deeper into one climate issue. Join the 30,000+ readers who have subscribed.
Richard Washington, professor of climate science at Oxford University, has seen the inside of a storm. To confirm whether cloud seeding could actually occur breeding record-breaking rainhe once boarded a plane that was riding a thundercloud over the South Africa-Mozambique border.
Read more: Don’t blame Dubai’s downpour on cloud seeding – the storm was too much for humans to deal with
“Our mission was to fly through the most active part of the storm, measure it, fly through again dumping a load of dry ice debris, turn hard and fly through for a final measurement,” he says.
“Other than the fun of flying through the center of a thunderstorm in a Learjet, I didn’t think much of the time I was lucky enough to be a part of that project. Until I heard about the recent freakout in Dubai.”
What caused the flood?
There are no two identical clouds to compare the outcome of the ceiling with, Washington says, so it is impossible to prove whether this technique can change the outcome of a single storm. But by flying many missions, half with cloud seeding and half without, and measuring rainfall in between, meteorologists eventually showed that cloud seeding modulated rainfall rates in some storms.
However, that was not the cause of the Dubai floods.
“The UAE has apparently been running a cloud seeding project, the UAE Research Program for Improved Rainfall Science, for several years. Their approach is to send hygroscopic (water-attracting) salt flares from aircraft into warm cumulus clouds,” says Washington.
“So, could seeding build a massive storm system the size of France? Let us be clear, that would be like wind stopping an intercity train going full tilt. And the seed flights didn’t happen that day either. The kind of deep, large-scale clouds that formed on April 16 are not the target of the experiment.”
For Washington, the most relevant atmospheric experiment is the one we all engage in daily.
“The interesting thing is that people have a hard time coming to grips with the fact that 2,400 gigatons of carbon (our total emissions since pre-industrial times) could make a difference to the climate, but the an idea that is shared. hygroscopic flames that make 18 months worth of rain in one day.”
The experiment on our lives
A warmer atmosphere holds more moisture, which can fall as rain. Although last week’s deluge was unusual, the Arabian Peninsula usually receives more of its precipitation in heavy bursts than steady showers.
The latest assessment by the Intergovernmental Panel on Climate Change (IPCC) did not predict future rainfall trends for the region but said global warming is expected to make such violent downpours more frequent and more intense.
It is not water, but heat, that is likely to kill more people as temperatures rise in this part of the world. Tom Matthews (Loughborough University) and Colin Raymond (California Institute of Technology) are scientists who study the changing climate and its effect on our bodies.
Read more: Global warming now pushing heat into territory humans cannot tolerate
During human evolution, the wet-bulb temperature (as hot as it is when you subtract the cooling effect of evaporating moisture, like sweat on your skin) rarely, if ever, exceeded 35 °C. At this threshold the air is so hot and humid that you cannot lower your temperature to a safe level by sweating. You overheat and, without urgent medical help, you die.
“The frequency of punishing wet-bulb temperatures has more than doubled worldwide since 1979, and in some of the hottest and most humid places on earth, such as the coastal United Arab Emirates, temperatures of “Wet bulb has already grown above 35°C,” Matthews and Raymond say.
“The climate envelope is pushing into territory that our physiology cannot follow.”
Fearing how quickly our climate is becoming irreversible, some scientists have called for emergency measures to be put in place. Peter Irvine, lecturer in earth sciences at UCL suggests softening the sun by pumping microscopic particles into the upper atmosphere to reflect some of its rays.
Read more: Why solar mitigation could be an effective tool in the fight against climate change
Trying to mimic the cooling effect of volcanic eruptions but on a permanent basis (until, presumably, greenhouse gas concentrations can be brought back to safe levels) is another mistake with the atmosphere. These layers of gas around our planet have sustained life by keeping temperatures stable and harmful radiation out.
Irvine admits that artificially cooling the Earth in this way is risky, but argues that the side effects – such as changing wind and rainfall patterns, acid rain and slowing the recovery of the ozone layer – “pale in comparison with the impacts of climate change”.
Catriona McKinnon, professor of political theory at the University of Reading, has other concerns attempt to manage solar radiation in this way, including the question of who has the right to regulate the global thermostat.
Read more: Time is running out on climate change, but geopolitics has its own dangers
As humanity contemplates another large-scale experiment in our atmosphere, there is another, even bigger one, waiting to be solved. The solution is simple: stop burning fossil fuels.
This article from The Conversation is republished under a Creative Commons license. Read the original article.
