[Marxism] Ocean Warming Is Accelerating Faster Than Thought, New Research Finds

Louis Proyect lnp3 at panix.com
Thu Jan 10 13:13:14 MST 2019


NY Times, Jan. 10, 2019
Ocean Warming Is Accelerating Faster Than Thought, New Research Finds
By Kendra Pierre-Louis

Scientists say the warming of the world’s oceans is accelerating more 
quickly than previously thought, a finding with dire implications for 
climate change because almost all of the heat trapped by greenhouse 
gases ends up stored in oceans.

A new analysis, published Thursday in the journal Science, found that 
the oceans are heating up 40 percent faster on average than a United 
Nations panel estimated five years ago. The researchers also concluded 
that ocean temperatures have broken records for several straight years.

“2018 is going to be the warmest year on record for the Earth’s oceans,” 
said Zeke Hausfather, an energy systems analyst at the independent 
climate research group Berkeley Earth and an author of the study. “As 
2017 was the warmest year, and 2016 was the warmest year.”

As the planet has warmed, the oceans have provided a critical buffer, 
slowing the effects of climate change by absorbing 93 percent of the 
heat trapped by human greenhouse gas emissions. But the escalating water 
temperatures are already killing off marine ecosystems, raising sea 
levels and making hurricanes more destructive.

As the oceans continue to heat up, those effects will become more 
catastrophic. Coral reefs, whose fish provide key sources of protein to 
millions of people, will come under increasing stress; a fifth of them 
have already died in the last three years. Rainier, more powerful storms 
like Hurricane Harvey in 2017 and Hurricane Florence in 2018 will become 
more common, and coastlines around the world will flood more frequently.

Because they play such a critical role in global warming, oceans are one 
of the most important areas of research for climate scientists. Average 
ocean temperatures are also a consistent way to track the effects of 
greenhouse gas emissions because they are not influenced much by 
short-term weather patterns, Mr. Hausfather said.

“Oceans are really the best thermometer we have for changes in the 
Earth,” he said.

But, historically, understanding ocean temperatures has also been 
difficult. An authoritative United Nations report, issued in 2014 by the 
Intergovernmental Panel on Climate Change, presented five different 
estimates of ocean heat, but they all showed less warming than the 
levels projected by computer climate models — suggesting that either the 
ocean heat measurements or the climate models were inaccurate.

Since the early 2000s, scientists have measured ocean heat using a 
network of drifting floats called Argo, named after Jason’s ship in 
Greek mythology. The floats measure the temperature and saltiness of the 
upper 6,500 feet of the ocean and upload the data via satellites.

But before Argo, researchers relied on expendable bathythermographs, a 
sort of temperature sensor that ships lowered into the ocean with a 
copper wire. The wire transferred data from the sensor onto the ship for 
recording, until the wire broke and the sensor drifted away.

That method was subject to uncertainties, especially around measurement 
depth, that hamper today’s scientists as they stitch together 
temperature records into a global picture.

In the new analysis, Mr. Hausfather and his colleagues assessed three 
recent studies that better accounted for instrument biases in the 
historical record. The results converged at an estimate of ocean warming 
that was higher than the I.P.C.C. predicted and more in line with the 
climate models.

The researchers also reviewed a fourth study that had used a novel 
method to estimate ocean temperatures over time and had also found that 
the world’s oceans were heating faster than the I.P.C.C. prediction. But 
that study contained an error that caused its authors to revise their 
estimates downward, suggesting that ocean warming was less of a problem 
than they originally reported.

As it turned out, the downward revision brought that study’s estimates 
much closer to the new consensus. “The correction made it agree a lot 
better with the other new observational records,” Mr. Hausfather said. 
“Previously it showed significantly more warming than anyone, and that 
was potentially worrisome because it meant our observational estimates 
might be problematic. Now their best estimate is pretty much dead-on 
with the other three recent studies.”

The scientists who published the four studies were not trying to make 
their results align, Mr. Hausfather said. “The groups who were working 
on ocean heat observations, they’re not climate modelers,” he said. 
“They’re not particularly concerned with whether or not their 
observations agree or disagree with climate models.”

Laure Zanna, an associate professor of climate physics at the University 
of Oxford who was not involved in the study, said the new research was 
“a very nice summary of what we know of the ocean and how far the new 
estimates have come together.”

Dr. Zanna was an author of a recent study that used existing data to 
estimate ocean temperatures dating back to 1871. The goal was to figure 
out places where sea level rise might happen even faster than expected 
because of the way ocean currents redistribute heat, allowing regions 
that are especially at risk to better plan for those changes.

As the oceans warm, sea levels rise because warmer water takes up more 
space than colder water. In fact, most of the sea level rise observed to 
date is because of this thermal expansion, not melting ice caps.

“We are warming the planet but the ocean is not warming evenly, so 
different places warm more than others,” said Dr. Zanna. “And so the 
first consequence will be that sea level will be different in different 
places depending on the warming.”

Though the new findings provide a grim forecast for the future of the 
oceans, Mr. Hausfather said that efforts to mitigate global warming, 
including the 2015 Paris climate agreement, would help. “I think there’s 
some reason for confidence that we’ll avoid the worst-case outcomes,” he 
said, “even if we’re not on track for the outcomes we want.”

Kendra Pierre-Louis is a reporter on the climate team. Before joining 
The Times in 2017, she covered science and the environment for Popular 
Science. @kendrawrites



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