ANALYSIS | When it comes to climate change, we should be paying more attention to our oceans | 24CA News
By now, most individuals are effectively conscious that 2023 was the most popular 12 months on report, coming in at 1.48 C hotter than the pre-industrial common from 1850-1900. This beat out 2016’s report of 1.25 C.
In local weather phrases, a rise in warming by 0.23 C is appreciable and local weather scientists are nonetheless making an attempt to determine why it occurred.
Was 2023 only a huge blip on the upward pattern of worldwide warming? Perhaps. Scientists are attempting to tease out all of the potential contributors.
But one of many issues that’s inarguably a contributor is the continued warming of our oceans
Last 12 months, our oceans have been the most popular on report. It was the primary 12 months wherein the common international sea floor temperatures (SST) — that’s, temperatures of the higher metre of water — surpassed 1 C in comparison with pre-industrial ranges.
Then there’s the ocean warmth content material (OHC), which is the temperature 2,000 metres under the floor. That, too, was at a report excessive in 2023. And that is of explicit concern as a result of OHC is a essential local weather indicator. Our oceans, which cowl greater than 70 per cent of the planet, retailer greater than 90 per cent of Earth’s extra warmth.
Just how a lot warmth did our oceans soak up final 12 months?
To put it in perspective, Zeke Hausfather, a analysis scientist at Berkeley Earth, a non-profit, unbiased local weather evaluation group, mentioned that we added 15 zettajoules of vitality to the oceans. That’s the equal to a billion trillion joules — or the equal of 25 occasions of all of the vitality utilized by humanity.
“It’s a pretty mind–bogglingly big number,” he mentioned.
And that ocean warmth content material is regularly rising. The extra CO2 we pump into the environment, the extra the oceans will take in.
We could also be forgiven for not paying as a lot consideration to the oceans as we must always. After all, as human beings, we have a look at international warmth because it happens on the floor as a result of that is the place we reside, that is what we expertise.
But for local weather scientists, the oceans are a essential indicator.
“For climate scientists who think about the climate system as a whole … the oceans are the most important thing,” mentioned Simon Donner, a local weather scientist and professor on the University of British Columbia. “It’s because they cover two–thirds of the planet, they’re very deep and they’re made up of water, not air. And water has got a high heat capacity.
“So they’re just like the planet’s nice warmth sink.”
Looking at 2023
Taking a look at just the oceans, there were many different contributors to 2023’s record heat.
First, there was an El Niño. Though it wasn’t a super event, as it was in 2015-16, it’s still been fairly significant. This warming of the central Pacific Ocean tends to produce an increase in the global temperature. But typically there is a lag, meaning the warmer temperatures aren’t seen until the year following the start of an El Niño.
“This 12 months has been uncommon, even for an El Niño. If we have a look at proper now, globally, [the SST is] about … 21.0. C. By SST knowledge, that is about 0.2 C above the place we have been at the moment in 2016, which is the final huge El Niño occasion,” said Hausfather. “And 2016 was, to be trustworthy, a a lot larger El Niño occasion. And so you already know, a 0.2 C improve relative to then in eight years is a bit of worrying.”
But Hausfather and Donner believe part of this may have been because we came from a “triple-dip” La Niña, the little sister to El Niño where ocean temperatures are cooler than normal. Those three years — from 2020 through 2022 —could have masked the warming, they say.
There were other ocean phenomena that contributed to the warmth.
The North Atlantic experienced a marine heat wave, which is a prolonged warmth in a specific area of the ocean. That’s why we saw hot tub-like temperatures off the coast of Florida.
And the North Atlantic wasn’t the only hot spot.
“There are marine warmth waves in basins throughout: within the Atlantic, each north and south; [the] Indian Ocean, Pacific Ocean,” said Josh Willis, a climate scientist with NASA’s Jet Propulsion Laboratory. “There are these floor temperature areas which can be simply unusually heat. And a few of that has additionally added to [last] 12 months’s report.”
‘The genie doesn’t go back in the bottle’
All of this — El Niño, the record-breaking sea surface temperatures, the increase in ocean heat content, the marine heat waves — has far-reaching consequences.
Coral reefs are particularly sensitive to ocean temperature changes, which cause mass coral bleaching events. This is when critical algae is forced out of the reef’s living tissue, turning them from beautiful bright colours to white. The reef isn’t dead, but it is more susceptible to mortality.
Then there’s the influence on marine life, which has financial and sustainability challenges.
“The ocean ecosystem is admittedly essential for all times on Earth, together with ours,” Willis said. “And it is beneath monumental strain. And it is strain that the majority of us do not see.”
Coral reefs in the Florida Keys have been decimated by disease, human activity and rising ocean temperatures. CBC’s international climate correspondent Susan Ormiston met the scientists engineering new coral in a lab and planting them in the wild to try to restore a critical ecosystem.
And there’s the most pressing issue for humans: rising sea levels.
Willis noted that it takes a long time to add heat to the ocean and a lot of heat to change its temperature. As the oceans warm, the water “actually stands taller.”
And rising sea levels can’t be reversed.
The Intergovernmental Panel on Climate Change’s latest report famous that, sea stage rise is “unavoidable for hundreds of years to millennia resulting from persevering with deep ocean warming and ice sheet soften, and sea ranges will stay elevated for hundreds of years.”
“The genie would not return within the bottle. Once the ocean ranges have risen, the percentages of us having the ability to make them fall once more are very, very small,” said Willis.
While we may not be able to reverse it, there is one solution in order to prevent things from becoming far worse: moving away from fossil fuels.
“Everything’s absorbing extra warmth as a result of we hold including greenhouse gases to the environment,” Donner said. “If we would like it to cease absorbing extra warmth, we have to cease that.”
