Circumstantial evidence shows that: climate change The deadly deluge that inundated Dubai and other parts of the Persian Gulf is getting worse, but scientists have failed to discover the definitive fingerprints of greenhouse gas-induced warming they have seen in other extreme weather events, a new report has found.
In just one day last week, parts of the United Arab Emirates, Oman and Saudi Arabia had 10% to 40% more rain than in a world without 1.2 degrees Celsius (2.2 degrees); this killed at least two dozen people in parts of the United Arab Emirates, Oman and Saudi Arabia. Fahrenheit) warming from burning coal, oil and natural gas since the mid-19th century, scientists at World Weather Attribution said Thursday in a breaking study that is too new to be peer-reviewed.
At at least one point, a record 11 inches (28.6 centimeters) of rain fell in just 24 hours; This was more than twice the annual average and paralyzed the bustling city in the desert where skyscrapers usually stand.
A key tool in WWA’s more than 60 historical reports was to create computer simulations that compared a real weather event to a fictional world without climate change; However, in the case of Dubai, there was not enough data for these simulations to make such a calculation. . But the other key tool they used, analysis of decades of historical observations, showed a 10% to 40% increase in precipitation amounts.
Even without computer simulations, clues continue to point to climate change, scientists said.
“It’s not a very clear fingerprint, but we have a lot of circumstantial evidence to say we’re seeing this increase,” the Imperial College of London climate scientist said. Friederike Ottois the person who coordinates the attribution work team. “This is what we expect from physics. “This is what we expect from other studies in this area and other studies around the world, and there is nothing else that can explain this increase.”
There is an effect that has been known for a long time in physics; that the air holds 7% more moisture for every degree Celsius (4% for every degree Fahrenheit).
Otto said he was confident in the outcome, but said it was one of the most difficult attribution studies the team had undertaken.
El Niño, a natural warming that occurs occasionally in the central Pacific and alters weather systems around the world, is a big factor, the report said. These heavy downpours in the Gulf have happened in the past, but only during El Niño. Past floods have become worse, researchers said; Scientists have long said that this would happen in many parts of the world as the world warms.
Study co-author Mansour Almazroui, from the Center of Excellence for Climate Change Research (CECCR) at King Abdulaziz University in Saudi Arabia, said this flood, which came from two separate and nearly simultaneous storm systems, could not have happened without El Niño. Otto added that this would not be the case if there were no human-caused climate change.
Because rainfall amounts vary by region and due to a lack of data, the report was unable to put a figure on whether climate change is increasing the likelihood of such showers in Dubai; but Otto estimated that the chances of this happening are currently about three times higher. compared to pre-industrial times.
The report and its authors poured cold water on speculation that the UAE’s cloud seeding had anything to do with the amount or chance of rain. Many scientists dispute the effectiveness of cloud seeding in general. Despite this, the clouds in the storm system were not seeded, the report stated. Otto said the results (if any) of cloud seeding are generally faster. And this storm was predicted days in advance.
“Such precipitation never comes from cloud seeding,” Almazroui said at Thursday’s press conference.
Andrew Weaver, a climate scientist at the University of Victoria in Canada, said that although the authors used well-established techniques and that is what scientists expect about climate change, conclusions should not be drawn when there is a disagreement between computer simulations and observations. part of the research.
Several other scientists said this was a strong enough case that greenhouse gas emissions were a factor.
Malte Meinshausen, a climate scientist at Australia’s University of Melbourne, called Thursday’s study “a well-balanced, impressively detailed and sufficiently conservative assessment.”
“This study, combined with theory and attribution studies associated with other increasingly frequent extreme rain and flood events around the world, provides compelling evidence that climate warming is supercharging the recent extreme rainfall and flood event in the UAE and Oman,” said climate scientist Jonathan. said. Overpeck, Dean of the School of Environment at the University of Michigan. “This is what global warming is becoming more and more like; more severe climate extremes and human suffering.”
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