Did climate change make Dubai’s deadly flooding worse? Scientiststhink it’s very likely
Circumstantial evidence points to cli‐ mate change as worsening the deadly deluge that just flooded Dubai and other parts of the Persian Gulf, but scientists didn't discover the defini‐ tive fingerprints of greenhouse gastriggered warming they have seen in other extreme weather events, a new report found.
Between 10 per cent and 40 per cent more rain fell in just one day last week than it would have in a world without the 1.2 degrees Celsius from the burning of coal, oil and natural gas since the mid-19th century, scien‐ tists at World Weather Attribution said Thursday in a flash study that is too new to be peer-reviewed.
In at least one spot, a record 28.6 centimetres of rain fell in just 24 hours, more than twice the yearly av‐ erage, paralysing the usually bustling city of skyscrapers in a desert.
Climate change is creating a ‘cock‐ tail’ of health hazards for 2.4 billion workers These European countries could lose more than 30 days of com‐ fortable weather a year by 2100
Heavy rains and flooding killed at least two dozen people in the United Arab Emirates, Oman and parts of Saudi Arabia.
How does climate change impact rainfall?
One of the key tools in WWA's more than 60 past reports has been creat‐ ing computer simulations that com‐ pare an actual weather event to a fic‐ tional world without climate change.
In the Dubai case there wasn’t enough data for those simulations to make such a calculation. But analysis of decades of past observations, the other main tool they use, showed the 10 per cent to 40 per cent bump in rainfall amounts.
Even without computer simula‐ tions, the clues kept pointing at cli‐ mate change, scientists said.
“It’s not such a clear fingerprint, but we have lots of other circumstan‐ tial evidence, other lines of evidence that tell us that we see this increase,” said Imperial College of London cli‐ mate scientist Friederike Otto, who coordinates the attribution study team.
It’s what we expect from physics. It’s what we expect from other studies that have been done in the area, from other studies around the world, and there’s nothing else that’s going on that could explain this increase. Friederike Otto World Weather Attri‐ bution
“It’s what we expect from physics. It’s what we expect from other studies that have been done in the area, from other studies around the world, and there’s nothing else that’s going on that could explain this increase.”
There is a long-known effect in physics that finds the air holds 7 per cent more moisture with every degree Celsius.
Otto said she has confidence in the conclusion, but said this was one of the harder attribution studies the team has undertaken.
Flooding would not have hap‐ pened without El Niño
El Niño, which is a natural occasional warming of the central Pacific that changes weather systems worldwide, was a big factor, the report said.
These heavy Gulf downpours have happened in the past but only during an El Niño. And the researchers said those past deluges seem to be trend‐ ing heavier - something scientists have long said would happen in many parts of the world as the world war‐ ms.
This flooding, which came from two separate and near simultaneous storm systems, would not have hap‐ pened without El Niño, said study coauthor Mansour Almazroui of the Cen‐ tre of Excellence for Climate Change
Research (CECCR), King Abdulaziz University in Saudi Arabia. Nor would it have been like this without humancaused climate change, Otto added.
Because rainfall amounts varied over the region and the lack of data, the report couldn't put a figure on if climate change had increased the likelihood of downpours like this in Dubai, but Otto estimated that it's probably about three times more likely to happen now than in pre-in‐ dustrial times.
Did cloud seeding play a part in Dubai's heavy rain?
The report and its authors threw cold water on speculation that UAE cloud seeding had anything to do with the amount of rain or its likelihood.
Many scientists dispute cloud seeding's effectiveness in general. Even so, the clouds in the storm sys‐ tem were not seeded, the report said. And the results of cloud seeding, if any, in general are more immediate, Otto said. And this storm was forecast days in advance.
“This type of rainfall never comes from cloud seeding,” Almazroui said in a Thursday news conference.
Experts say cloud seeding isn’t to blame for Dubai’s record rainfall: What caused the floods? Rapid mili‐ tarisation jeopardising climate, claim NGOs
While the authors use well-estab‐ lished techniques and this is what sci‐ entists expect with climate change, when there's a disagreement be‐ tween computer simulations and ob‐ servations, conclusions shouldn't be drawn, said University of Victoria, Canada, climate scientist Andrew Weaver, who wasn't part of the re‐ search.
It's a strong enough case that greenhouse gas emissions are a fac‐ tor, several other outside scientists said.
University of Melbourne, Australia, climate scientist Malte Meinshausen called Thursday’s study “a well-bal‐ anced, impressively detailed and ade‐ quately cautious assessment.”
“This work, when combined with theory and attribution studies associ‐ ated with the increasingly frequent other extreme rain and flooding even‐ ts around the world, makes the con‐ vincing case that climate warming su‐ percharged the recent extreme rain‐ fall and flooding event UAE and Oman,” said climate scientist Jonathan Overpeck, dean of the Uni‐ versity of Michigan's environment school.
“This is what global warming in‐ creasingly looks like - more severe cli‐ mate extremes and human suffering.”