2023’s Atlantic Ocean heat, low Antarctic sea ice give glimpse of hotter world: study
‘Essential to find out why this is happening’
Off the charts “crazy” heat in the North Atlantic Ocean and recordsmashing Antarctic sea ice lows last year are far more severe than what Earth’s supposed to get with current warming levels.
They are more like what happens at twice this amount of warming, a new study said.
The study’s main author worries it’s a “harbinger of what’s coming in the next decades” and it’s got him not just concerned, but wondering why those two climate indicators were so beyond what was expected.
A study in the Bulletin of the American Meteorological Society charted the North Atlantic sea temperature and the Antarctic sea ice halfway across the globe against long-accepted computer simulations. Sea ice levels that low and North Atlantic temperatures that much above normal are supposed to occur regularly in a world that has warmed 3 C since pre-industrial times.
But that’s not where Earth is right now.
Last year, a record hot year by far, the world was 1.48 C warmer than pre-industrial times, according to the European climate agency Copernicus.
And, over the long-term of decades, which is what scientists use, the world is at about 1.2 C warmer than normal.
“The climate of 2023 with all the disasters, you know, with all the wildfires in Canada and all the flooding events in Europe and everything, you can interpret this as, this what we will have every year. Year after year after year in the three-degree world,” said study author Till Kuhlbrodt, a climate scientist at the National Centre for Atmospheric Sciences and the University of Reading in England. “You don’t want to go there.”
That’s still a few decades away, he said.
It leads to the big question of why or how did this happen last year?
At best it’s a “freak event” on top of a strong El Niño that changes weather patterns worldwide and when that ends things return to near what now passes for normal, Kuhlbrodt said.
“If it’s not like that, and the North Atlantic stays in this crazy area,” then the Northern Hemisphere is in deep trouble, Kuhlbrodt said. “And then it’s absolutely essential to find out why this is happening and how bad it’s gonna get.”
Kuhlbrodt looked at 2023 temperature levels in the North Atlantic. Last week the anomaly — or difference above the 1991-2020 average — was “so far out of whack” that it was the type of event that it would randomly happen only once in 284,000 years, said University of Miami tropical scientist Brian McNoldy, who wasn’t part of the study.
Next week or so, the North Atlantic will have gone a full year of nonstop, record-breaking sea surface temperatures, McNoldy said, adding “it’s not just record-breaking, it’s blowing past records.”
In the past few weeks, Antarctic sea ice has returned to hovering at or just below record low levels, but not as off the charts as before, Kuhlbrodt said.
Kuhlbrodt and several other outside scientists said it’s not climate computer simulations that are off because they are working elsewhere and have proven right over time. Though they could be underestimating impacts of warming, they said.
So that leaves Kuhlbrodt and others wondering if it’s a sign of the acceleration of warming or if some kind of other factor connects the North Atlantic and Antarctic effects.
“There is no doubt that the impacts (of warming) are accelerating and much more visible than they were in the past,” said University of Arizona climate scientist Kathy Jacobs, who wasn’t part of the study.
Saying these two conditions provide a glimpse of a three-degree world is not the same as saying conditions across the globe now are a preview of that hotter world, just a few places, Jacobs said in an email.
French climate scientist Valerie Masson-Delmotte, who wasn’t part of the study, said the Antarctic sea ice and hotter North Atlantic “show how with ongoing warming we are entering into uncharted territory and we need to anticipate and better prepare for these (low-likelihood, but high-impact) outcomes.”