This summer’s weather was relentless, crowded with the type of record-smashing extremes that scientists have long warned about.
The season ends Wednesday, and not a moment too soon. Summer featured floods that killed hundreds of people and caused more than $50 billion in losses around the globe, from Louisiana to China, India, Europe and the Sudan. Meanwhile, droughts parched croplands and wildfires burned in California, Canada and India. Toss in record heat that went on and on.
From June to August, there were at least 10 weather disasters that each caused more than $1 billion in losses, according to insurance industry tallies. With summer weather now seemingly stretching from May to September, extreme weather in that span killed more than 2,000 people. And that’s without a major hurricane hitting a big U.S. city, although the Pacific had its share of deadly and costly storms.
“We’ve experienced an increasing number and a disturbing number of weather extremes this summer,” U.S. National Weather Service Director Louis Uccellini said.
While flooding made the news, the “sneaky” thing about the summer was heat that did not even ease at night, said Deke Arndt, climate monitoring chief at the federal National Centers for Environmental Information in Asheville, North Carolina. When temperatures drop to below 72 at night, it allows the body to recharge, plants to grow and air conditioners to be shut off. But this year that didn’t happen enough.
The United States as a nation set a record for the hottest nighttime temperatures on average this summer, Arndt said. Tallahassee, Florida, for example, went 74 consecutive days in which the nighttime temperature didn’t dip below 72.
“This is one of the clearest signals we expect for climate change,” said Mark Bove, a New Jersey-based senior research meteorologist for re-insurance giant Munich RE, which tracks natural disasters. “It keeps a blanket on you, particularly at night. We cannot radiate the heat away at night as the planet used to.”
The extra heat — both in the air and oceans — puts a lot of extra moisture in the air, which then comes down as more extreme downpours, said Kevin Trenberth, a senior scientist at the National Center for Atmospheric Research. And when an area is already dry, droughts worsen because warmer air takes more water out of the ground.
NASA chief climate scientist Gavin Schmidt said the records keep showing the planet warming and “since we kind of predicted these things, we know what we’re talking about.”
Perhaps the most noticeable prediction was a 1988 study by James Hansen, former head of NASA’s Goddard Institute for Space Studies.
In that study, Hansen forecast what would probably happen to Earth’s climate. He not only got the global temperature rise about right, but he also forecast big changes in the number of days when the overnight temperatures would not go below 75 and the daytime highs would exceed 95 in four cities by the 2010s.
He was right — or underestimated how hot it would be — in six of eight categories.
“The fact it’s come out with more or less around what was predicted is not surprising,” Hansen said. “The summer is when things show up easiest because the natural variability is the least in the summer. You notice the change more readily in the warm season.”