By Helen Ecker··an average:
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Tropical Storm Debbie, which is causing flooding in several parts of the United States, looks exactly like what climate scientists warn about: Climate change can cause hurricanes and storms that bring heavy rain. “These types of rainmakers are becoming more and more common.”
Debby made landfall in Florida on Monday as a Category 1 hurricane. Locally, 450 mm of rain has already fallen here. The hurricane has since weakened to a storm. But it is expected that Debby could cause catastrophic flooding in the coming days. In addition, a hurricane warning is in effect for coastal areas as the storm moves slowly northward.
Rainfall is likely to be widespread in the US states of Georgia, South and North Carolina. Locally, 600 to 700 mm is expected. Maurice Middendorp from Buienradar: “Part of Debye is now above sea level, and due to the warm sea water, heavy rains and thunderstorms could occur again and again. For comparison: 850 mm falls in the Netherlands in a whole year.”
Climate change
One reason tropical storms are dumping more rain today is that they are moving more slowly than they did 75 years ago. “That’s because the North and South Poles are warming faster than the rest of the world, which means the winds that drive tropical cyclones are slower,” Middendorp says.
This means that the storms stay in the same place longer, and therefore can produce more rain. KNMI wrote: “Because Debby barely moves from its location, rain that originates over the sea is constantly being pushed to land, and almost constant (heavy) rainfall is expected over parts of North Carolina and South Carolina in the coming days. Georgia.”
In addition, with every degree of global warming, the air contains 7 percent more moisture. This rain can then fall in heavy showers. Nadia Bloemendaal from KNMI and Vrije Universiteit Amsterdam studies the impact of climate on storms and hurricanes.
“We now know a few things for sure,” she says. “Hurricanes bring more rain when they make landfall because warm air holds more moisture. Debbie is a true rainmaker. And these types of rainmakers are becoming increasingly common as a result of climate change.”
sea water temperature
A storm could develop into a hurricane if the sea temperature was 27 degrees, Bloemendahl notes. But the ocean is warmer than that in many places right now. “Debbie formed over sea temperatures of 31 degrees. That means the storm could have a lot more energy.”
There are other ways climate change is affecting storms, too. According to Bloemendaal, rising sea levels could lead to more frequent storms. “A huge wind mass pushes waves up into the ocean. Near the coast, that translates into a storm surge. The stronger the wind, the stronger the storm surge. Then sea level rise comes on top of that.”
For Dutch people, these types of extreme weather events in the United States can seem like a far-fetched proposition, but according to Bloemendaal, that’s no excuse. “The Dutch also live in the Caribbean. Hurricanes and tropical storms happen there. We need to pay more attention to that.”
painful
Moreover, she believes: “In America they have the money to prepare well for this. But take Haiti or the Dominican Republic. The situation there is terrible when the population has to deal with more violent storms and hurricanes. And the people there have contributed to that.” There is little impact on global warming, but they are still facing its consequences.
Moreover, the United States will increasingly have to deal with more severe consequences in the future. “In 30 years, Florida is projected to be uninsured against extreme weather events. That’s a big sign for the future.”
The Netherlands may also have to deal more often with hurricanes coming from the United States as they cross the Atlantic. “The hurricane has to be strong enough to deal with the jet stream that it then encounters,” says Bloemendaal. “But the chances of hurricanes surviving this crossing are increasing, because they are becoming stronger and the sea water temperature is rising.”
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