A major study claimed the oceans were warming much faster than previously thought. But researchers now say they can’t necessarily make that claim.
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| The sun sets over sea ice floating on the Victoria Strait along the Northwest Passage in the Canadian Arctic Archipelago during the summer of 2017. (AP Photo/David Goldman) |
Scientists behind a major study that claimed the
Earth’s oceans are warming faster than previously thought now say their
work contained inadvertent errors that made their conclusions seem more
certain than they actually are.
Two weeks after
the high-profile study was published in the journal Nature, its authors
have submitted corrections to the publication. The Scripps Institution
of Oceanography, home to several of the researchers involved, also noted
the problems in the scientists' work and corrected a news release
on its website, which previously had asserted that the study detailed
how the Earth’s oceans “have absorbed 60 percent more heat than
previously thought.”
“Unfortunately, we made
mistakes here,” said Ralph Keeling, a climate scientist at Scripps, who
was a co-author of the study. “I think the main lesson is that you work
as fast as you can to fix mistakes when you find them.”
The
central problem, according to Keeling, came in how the researchers
dealt with the uncertainty in their measurements. As a result, the
findings suffer from too much doubt to definitively support the paper’s
conclusion about how much heat the oceans have absorbed over time.
The
central conclusion of the study — that oceans are retaining ever more
energy as more heat is being trapped within Earth’s climate system each
year — is in line with other studies that have drawn similar
conclusions. And it hasn’t changed much despite the errors. But Keeling
said the authors' miscalculations mean there is a much larger margin of
error in the findings, which means researchers can weigh in with less
certainty than they thought.
“I accept
responsibility for what happened because it’s my role to make sure that
those kind of details got conveyed,” Keeling said. (He has published a
more detailed explanation of what happened here.)
The
study’s lead author was Laure Resplandy of Princeton University. Other
researchers were with institutions in China, Paris, Germany and the U.S.
National Center for Atmospheric Research and Geophysical Fluid Dynamics
Laboratory.
“Maintaining the accuracy of the
scientific record is of primary importance to us as publishers and we
recognize our responsibility to correct errors in papers that we have
published,” Nature said in a statement to The Washington Post. “Issues
relating to this paper have been brought to Nature’s attention and we
are looking into them carefully. We take all concerns related to papers
we have published very seriously and will issue an update once further
information is available.”
The original study,
which appeared Oct. 31, derived a new method for measuring how much
heat is being absorbed by the oceans. Essentially, the authors measured
the volume of gases, specifically oxygen and carbon dioxide, that have
escaped the ocean in recent decades and headed into the atmosphere as it
heats up. They found that the warming “is at the high end of previous
estimates” and suggested that as a result, the rate of global warming
itself could be more accelerated.
The
results, wrote the authors, may suggest there is less time than
previously thought to curb greenhouse gas emissions. The study drew
considerable media attention, including from The Post.
However, not long after publication, an independent Britain-based researcher named Nicholas Lewis published a lengthy blog post saying he had found a “major problem” with the research.
“So
far as I can see, their method vastly underestimates the uncertainty,”
Lewis said in an interview Tuesday, “as well as biasing up
significantly, nearly 30 percent, the central estimate.”
Lewis
added that he tends “to read a large number of papers, and, having a
mathematics as well as a physics background, I tend to look at them
quite carefully, and see if they make sense. And where they don’t make
sense — with this one, it’s fairly obvious it didn’t make sense — I look
into them more deeply.”
Lewis
has argued in past studies and commentaries that climate scientists are
predicting too much warming because of their reliance on computer
simulations, and that current data from the planet itself suggests
global warming will be less severe than feared.
It
isn’t clear whether the authors agree with all of Lewis’s criticisms,
but Keeling said “we agree there were problems along the lines he
identified.”
Paul Durack, a research scientist
at the Lawrence Livermore National Laboratory in California, said that
promptly acknowledging the errors in the study “is the right approach in
the interests of transparency.”
But he added
in an email, “This study, although there are additional questions that
are arising now, confirms the long known result that the oceans have
been warming over the observed record, and the rate of warming has been
increasing,” he said.
Gavin
Schmidt, head of the NASA Goddard Institute for Space Studies, followed
the growing debate over the study closely on Twitter and said that
measurements about the uptake of heat in the oceans have been bedeviled
with data problems for some time — and that debuting new research in
this area is hard.
“Obviously you rely on your
co-authors and the reviewers to catch most problems, but things still
sometimes slip through,” Schmidt wrote in an email.
Schmidt
and Keeling agreed that other studies also support a higher level of
ocean heat content than the Intergovernmental Panel on Climate Change,
or IPCC, saw in a landmark 2013 report.
Overall, Schmidt said, the episode can be seen as a positive one.
“The
key is not whether mistakes are made, but how they are dealt with — and
the response from Laure and Ralph here is exemplary. No panic, but a
careful reexamination of their working — despite a somewhat hostile
environment,” he wrote.
“So, plus one for some
post-publication review, and plus one to the authors for reexamining the
whole calculation in a constructive way. We will all end up wiser.”
Links
- Oceans Warming Faster Than Anticipated, Giving Even Less Time To Stave Off Worst Impacts Of Climate Change, Study Finds
- Quantification of ocean heat uptake from changes in atmospheric O2 and CO2 composition
- The Oceans Are Heating Up Faster Than Expected
- Startling new research finds large buildup of heat in the oceans, suggesting a faster rate of global warming
- The world has just over a decade to get climate change under control, U.N. scientists say
- We expect energy-related CO2 emissions will increase once again in 2018 after growing in 2017
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