New Orleans is already a ‘Heat Island.’ Afterwards Ida Cuts the Strength
Last Sunday, Hurricane Si Ida landfall in Louisiana, tying the years to 2020 Hurricane Laura as the strongest storm to hit the state. Wind gusts of 150 miles per hour destroyed the electricity infrastructure, leaving one millions of people without power. All eight transfer lines to New Orleans snapped.
now the temperature is in the 90s, and violent humidity-summer, after all-plunged Louisiana into a crisis for many people: Without power, residents without generators also lack fans or aircon. The Entergy utility says the power may be irreversible in three weeks, but local officials warn it could be a month for some. “I’m not satisfied in 30 days, Entergy people aren’t satisfied in 30 days,” Louisiana governor John Bel Edwards SAYS at a press conference on Tuesday. “No one out there who needs power will be satisfied with that.”
The suffering is even worse in New Orleans and other cities that have already “heat islands”At the scene. These are areas where there are not enough trees or other green spaces where the built -up environment absorbs the energy of the sun during the day, slowly releasing it at night. The temperature in the city can be 20 degrees Fahrenheit hotter than in the neighboring villages. And here’s the worse news: An analysis published in July by the Climate Central research group that found the impact of the New Orleans island heat worse than any town in the United States.
If you know what climate-crisis hell looks like, this is it. “This whole region is already hot and humid until summer,” said Louisiana State University climate scientist Barry Keim, who is also the state’s climatologist. “And you messed up some of the effects of urban heat, which made it worse, and you knocked down the aircon system. It’s a recipe for disaster.”
Many factors make towns hot islands. Concrete, asphalt, and brick absorb heat very well. If the surrounding air cools at night, the dense materials can only release some of that heat, so they can still be warm when the sun rises the next day and provide more energy. “That’s why you get this reason to cook in the heat of the day,” said Portland State University climate adaptation scientist Vivek Shandas, who studied the island’s effect on heat in Portland, New Orleans, and several towns. After Hurricane Ida, he said, it looks like New Orleans is now facing a “few days of extreme heat.”
The structure of the built environment is also a major factor. Tall buildings absorb sunlight and block the wind, which can keep out the heat in urban areas. And the buildings themselves produce heat — especially factories — or exhale hot air from AC units.
Compare this to rural areas full of trees: When the sun enters a forest or grass, the vegetation absorbs that energy, but instead releases water vapor. In a sense, a green space “sweats” to cool the air, which is more tolerable to temperatures.
In an ideal world, every town is full of trees to keep it cool. But in a metropolis like New Orleans, Shandas said, the temperature can vary, even if block by block. Buildings made of brick retain much more heat than those made of wood, and fat freeways are absorbed by the sun. But if the buildings are surrounded by trees, and if there are a lot of green spaces like parks, all the green will help cool the air.
On one day in August last year, Shandas and other researchers collected 75,000 temperature measurements from around New Orleans. They know that the coolest places sit at almost 88 degrees, while the hottest places sit at 102 degrees. “It has to do with green space, it also has a lot to do with repairing buildings, as well as building materials,” Shandas said.