What’s unusual is that the current La Niña event has lasted two winters now and may even continue until 2023. If that happens, it would only be the third longest running La Niña since 1950.
“In general, we tend to see more frequent La Niña events, and they tend to be stronger. That’s actually the opposite of what most climate models say, “says Klotzbach.” There’s a lot of discussion about whether it’s natural variability. “
La Niña has all kinds of effects on the weather, she points out, not just hurricanes. It could worsen drought in the southwestern U.S., for example. Ultimately, a powerful combination of the effects of climate change and natural variability is hitting some parts of the world right now.
If a large number of hurricanes appear in the Atlantic this year, no one knows how likely they are to actually land, says Pastelok. But he added that he hoped people would be prepared for the worst, just in case: “With this sea level rise, I think the rise will be crazy if one of these systems reaches the east coast.”
However, the deadliest weather events in many parts of the world (including the United States) are heat waves, says Friederike Otto, a senior professor of climate science at the Grantham Institute for Climate Change and the Environment. Imperial College London.
And unusually early heat waves this year, for example in India (where temperatures hit a record 49.2 degrees Celsius in May), France (which recorded its first day of 40 degrees ever), and areas of the United States (where 100 million people have been advised to stay inland) are of particular concern, Otto says. “The health effects are usually worse in the first heat waves than in the summer afternoon, when our bodies have acclimatized.”
People should make sure to stay hydrated and avoid going out during the hottest part of the day, he advises. If you can’t stay cool enough at home, you may be able to access the air conditioning in a public building such as a library. “Take the heat really seriously,” Otto says.
Maybe it’s time to rethink architecture in places that were less accustomed to heat in the past, suggests Clare Heaviside, a researcher at the Institute of Environmental Design and Engineering at University College London. Due to the urban heat island effect, heat waves can be several degrees Celsius warmer in cities than in surrounding areas. Heaviside says this is sometimes exacerbated by air conditioning systems, which release heat into the atmosphere while keeping indoor spaces cool.
There are alternative ways to reduce the temperature inside buildings, he says, “You can replace the roof with a more reflective roof and it will reduce the local temperature of the urban heat island.” In a 2019 study, she and a colleague estimated that this could reduce deaths in an urban heat island area by 25 percent during a heat wave.
Although anthropogenic climate change is making heat waves more frequent, lasting, and more intense, Otto says, some countries still do not have widespread awareness of extreme heat events. “Many African countries do not have a definition of a heat wave, so weather services do not record or report if temperatures are unusual,” he said.
