New Orleans was already a “Heat Island”. Then Ida cut strength

On Sunday, a hurricane Ida landed in Louisiana, Relating to 2020 Hurricane Laura because it was the strongest storm the state has ever had. Winds of up to 150 mph damaged the electrical infrastructure millions of people without power. Eight transmission lines to New Orleans they were cut.

Now temperatures are in the 90s, and wild humidity — it’s summer, after all — is plunging Louisiana into a multi-layered crisis: powerless, even residents without generators will lack fans or air conditioning. The Entergy utility says energy will not be restored for three weeks, but local officials have warned that it could be a month for some. “I’m not happy with 30 days, Entergy people aren’t happy with 30 days,” Louisiana Gov. John Bel Edwards he said at a press conference on Tuesday. “No one who needs power is content with that.”

Misery is particularly severe in New Orleans and other cities that already make it up.heat islands”Landscape. They are places without enough trees or other green spaces, where the built environment absorbs the energy of the sun during the day, slowly releasing it at night. City temperatures can be 20 degrees Fahrenheit warmer than the surrounding rural areas. And here’s the extra bad news: An analysis According to a report by the Climate Central research team in July, it is the New Orleans heat island effect worse than any other city In the United States.

If you’re interested in finding out what the hell of a climate crisis is like, this is it. “This region is already hot and humid in the summer,” says Louisiana State University climatologist Barry Keim, who is also a state climatologist. “And you cause some impact on the hot island of the city, which only exacerbates that and you expel the air conditioning system. It’s a recipe for disaster.”

Several factors make cities hot islands. Concrete, asphalt and bricks absorb heat very well. When the surrounding air cools at night, these dense materials can only release some of that heat, so they can still stay warm the next day when the sun comes out and more energy is applied. “So you get this kind of cooking factor over many hot days,” says climate adaptation scientist Vivek Shandas, of Portland State University, when he studied the effect of the heat island. Portland, New Orleans and dozens of other cities. After Hurricane Ida, he says, it now appears that New Orleans is facing “excessive heat day chains.”

The structure of the built environment is also a major factor. Tall buildings absorb sunlight and block the wind, trapping heat from the center. Buildings themselves generate heat — especially factories — or hot air from air-conditioning units.

Compare it to rural areas full of trees: when the sun hits a forest or meadow, the vegetation absorbs that energy, but releases water vapor. In a sense, a green space “sweats” to cool the air, making temperatures much more bearable.

In an ideal world, every city would be full of trees to help cool off. Shandas says that in a metropolis like New Orleans, temperatures can change dramatically, even block by block. Brick buildings withstand heat better than wooden ones, and highway grease absorbs sunlight. But if the buildings are interspersed with trees and you have plenty of green space like parks, all of that greenery helps cool the air.

One day in August last year, Shandas and other researchers conducted 75,000 temperature measurements around New Orleans. The coolest environments were found to be around 88 degrees, and the warmest to 102 degrees. “It has a lot to do with green spaces, it also has a lot to do with building setup and building materials,” Shandas says.