by Circumstantial evidence suggests climate change is exacerbating the deadly deluge that just inundated Dubai and other parts of the Persian Gulf, but scientists haven’t found the definitive fingerprints of greenhouse gas warming they’ve seen in other extreme weather events, new report received.
Between 10 percent and 40 percent more it rained in one day last week than it would have in a world without the 1.2 degrees Celsius from burning coal, oil and natural gas since the mid-19th century, scientists at the World Weather Attribution said Thursday in a flash study that is too new to be peer-reviewed.
In at least one location, a record 28.6 centimeters of rain fell in just 24 hours, more than twice the annual average, paralyzing the normally bustling desert city of the sky.
Heavy rain and flooding have killed at least two dozen people in the United Arab Emirates, Oman and parts of Saudi Arabia.
How does climate change affect rainfall?
One of the key tools in WWA’s more than 60 previous reports is to create computer simulations that compare an actual weather event to a fictional world without climate change.
In the case of Dubai there was not enough data for those simulations to make such a calculation. But analysis over the years, the other main tool they use, has shown a 10 percent to 40 percent crash in rainfall amounts.
Even without computer simulations, the clues held focusing on climate changesaid scientists.
“It’s not such a clear fingerprint, but we have a lot of other circumstantial evidence, other lines of evidence that tell us that we see this increase,” said Imperial College of London climate scientist Friederike Otto, who coordinates the allocation study team .
“It’s what we expect from physics. That is what we expect from other studies that have been done in the field, from other studies around the world, and there is nothing else going on that could explain this increase.”
There is a long-known effect in physics that finds that the air holds 7 percent more moisture with every degree Celsius.
Otto said she is confident in the conclusion, but said this was one of the more difficult allocation studies the team has done.
Flooding would not have occurred without El Niño
El Ninothe occasional natural warming of the central Pacific Ocean that alters weather systems around the world is a major factor, the report said.
This heavy Gulf spill has only occurred during El Niño in the past. And the researchers said past floods appear to be trending heavier — something scientists have long said would happen in many parts of the world as the world warms.
This is a flood, which came from two separate and near simultaneous storm systems, would not have happened without El Niño, said study co-author Mansour Almazroui from the Center of Excellence for Climate Change Research (CECCR), King Abdulaziz University in Saudi Arabia. It wouldn’t be like this either without human-caused climate change, Otto said.
Because rainfall amounts varied across the region and the lack of data, the report was unable to put a figure on whether climate change has increased the likelihood of such a downpour in Dubai, but Otto reckoned it was likely three times more likely now. than in pre-industrial times.
Did cloud seeding play a role in Dubai’s heavy rain?
The report and its authors threw cold water on speculation that UAE cloud seeding was related to the amount or likelihood of rainfall.
Many scientists dispute the effectiveness of cloud seeding in general. However, the clouds were not seeded in the storm system, the report said. And the results of cloud seeding, if any, are generally more immediate, Otto said. And this storm was predicted days in advance.
“This type of rain does not come from cloud seeding,” Almazroui said at a news conference on Thursday.
Although the authors use established techniques and this is what scientists expect when it comes to climate change, when there is a disagreement between computer simulations and observations, conclusions should not be drawn, said climate scientist Andrew Weaver , University of Victoria, Canada, did not. t part of the research.
That’s a pretty strong case greenhouse gas emissions is a factor, said some other outside scientists.
Climate scientist Malte Meinshausen, University of Melbourne, Australia, called Thursday’s study “a well-balanced, impressively detailed and quite cautious assessment.”
“When this work is combined with theory and attribution studies of other increasingly frequent extreme rainfall and flood events around the world, it makes a convincing case that climate warming has outpaced the rainfall and flood event recently UAE and Oman,” said climate scientist Jonathan. Overpeck, Dean of the University of Michigan’s School of the Environment.
“This is what global warming looks like more than ever before – more extreme climates and human suffering.”
