During COP21, the 2015 UN Climate Change Conference in Paris, 196 parties adopted a legally binding international treaty on climate change to pursue efforts “to limit the temperature increase to 1.5°C above pre-industrial levels.”
But the European Union’s climate service reported recently that global warming exceeded 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, above pre-industrial levels for the first time in a 12-month period from February of last year to January.
A global temperature of 1.5 degrees above normal means the Earth's atmospheric system has double the energy compared to 1950, said Bob Bunting, with the Climate Adaptation Center in Sarasota.
"That's what drives weather events and extreme events around the planet," Bunting said. "In human history, right now we're having the warmest atmosphere that we've had since the beginning of the human race."
The impacts of a 'super El Niño'
Take El Niño, for instance. The phenomenon of warmer-than-average sea surface temperatures in the Pacific Ocean made this past winter wetter. And Bunting said when the temperature gets to two degrees centigrade above normal in the sea surface, not in the atmosphere, it becomes a “super El Niño.”
When that happens, it diverts the jet streams in different ways. A branch of the jet stream that comes in far south of its usual position comes in across California, in the southwest part of the U.S., and sometimes into the southeast part, which includes Florida.
“It hasn't been a happy event for all the tourists who come here, but it's actually broken the drought that we had here in 2023, where we had 23 inches of rain below normal. So, now we're above normal on rainfall for this year. And it's alleviating the drought, so it's not all bad.”Bob Bunting, Climate Adaption Center
“It's right at Super El Niño levels right now ... And so that's why our winter here, this year, has been so different than the one we had last year because we have this stream of high winds, which is way south of where it usually is. And it's moving the storm track way far south of where it used to be,” said Bunting.
So, Florida’s west coast has been seeing more clouds, more rain, and more cool weather than we're used to for this time of year.
“It hasn't been a happy event for all the tourists who come here, but it's actually broken the drought that we had here in 2023, where we had 23 inches of rain below normal. So, now we're above normal on rainfall for this year. And it's alleviating the drought, so it's not all bad,” he said.
But El Niño is expected to soon be replaced by its opposite, La Niña, where the water becomes colder than normal.
How La Niña could bring stronger hurricanes
Bunting said when this happens during hurricane season, the wind shear in the Atlantic, Caribbean and Gulf of Mexico goes down, allowing hurricanes to grow vertically. And when they do that, he said, the storms become more intense.
“As one moves from the surface to a higher level in the atmosphere, it's normal for the winds to increase. But when we have a La Niña, that increase is light compared to normal,” Bunting said. “That allows hurricanes, when they're forming, to sort of stack up and not get blown off their eyes, so to speak, the center of the storm."
El Niño and La Niña patterns themselves are normal, but climate warming is making them more extreme, said Bunting.
“When La Niña becomes a bigger event, that allows hurricanes to be stronger. When El Niño becomes a bigger event, it allows major excessive precipitation events all across the southern part of the United States,” Bunting said.
“It's just not about heat. It's about redistributing all the excess heat through the atmosphere and storm systems is the way that nature does that.”
Lowering the heat-trapping gases that 8 billion people are putting into the atmosphere is key to stabilizing the climate, Bunting said.
"Even if we do everything that all the countries have agreed to today, the climate is going to continue to warm to 2100 or so. So, for the next lifetime, the only real strategy we have locally is to adapt to what's coming," Bunting said.
The Climate Adaptation Center will release its hurricane forecast on April 4 at the University of South Florida Sarasota-Manatee campus.
