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In the United States and elsewhere, ocean research infrastructure is facing a funding crisis. The U.S. National Science Foundation recently proposed dismantling hundreds of deep-ocean observation instruments, though it reversed the decision after public outcry. Still, a lagging NOAA budget and cuts to federal research funding have slowed the deployment of U.S.-owned instruments that measure ocean metrics and left the future of Argo, a global fleet of robotic instruments drifting in the ocean, in question. In addition, the number of observational floats deployed by Europe, as well as the number of active European floats, has dropped steadily since about 2020.
A study published in Nature Climate Change quantifies the impact that changes in funding could have on ocean data. Through a series of experiments, the research team showed that even small changes to the availability of data within the Global Ocean Observing System (GOOS), a United Nations–supported network of ocean observations, would significantly decrease the quality of ocean heat information available to researchers, making global climate and weather predictions more difficult.
Without U.S. contributions to the network, for example, “we lose the capability to monitor ocean warming,” said Lijing Cheng, an oceanographer at the Chinese Academy of Sciences and coauthor of the new study. Cheng is a member of the World Meteorological Organization’s Ocean Observations Physics and Climate Panel, which evaluates the status of global ocean observation systems and recommends strategies to keep such systems sustainable.
“It’s a really important paper because it is addressing the precarity of our current global ocean observing system,” said Hilary Palevsky, a marine biogeochemist at Boston College who was not involved in the study.
Data Degradation
GOOS is a network of observing platforms, ship observations, buoys, and Argo floats that measure various essential ocean variables such as temperature, salinity, nutrients, biodiversity, and more. In particular, the network provides high-quality data on ocean heat content, a measurement of the amount of energy stored in Earth’s oceans. Scientists use ocean heat content to project global sea level rise, tropical cyclones and hurricanes, marine heat waves and their impacts on ecosystems and fisheries, and more.
“If we want to know how much the climate is impacting ocean ecosystems, we have to monitor ocean temperature and ocean heat content changes,” Cheng said.
According to Cheng, much of the information gathered about the health of ocean observation systems like GOOS is simply inventories—counts of how many observations exist. Rarely does anyone evaluate how the number of observations available affects the quality of the data, he said. And with various global threats to data stewardship and funding, making that assessment could be more important than ever.
To see how a hypothetical loss of GOOS observations could affect ocean heat content data, Cheng and the research team ran two experiments. First, they randomly removed 20%, 40%, 60%, and 80% of the available GOOS ocean heat content observations to mimic possible changes to the system. Losing these data degraded measurements of the global annual ocean heating rate in all cases, increasing the relative error of the measurement by about 33%, 57%, 79%, and 97%, respectively.
“That’s a really risky place for us as the global ocean sciences community to have any country play such a pivotal role.”
Next, they removed the datasets by country, creating hypothetical scenarios where a country’s entire contribution was deleted from the network. Removing data from the five countries with the highest contributions (the United States, Australia, Japan, France, and Germany) degraded ocean heating rate measurements significantly in each case. Removing data contributed by the United States, for example, increased the relative error of the global annual ocean heating rate measurement by 163%, making the measurement difficult to distinguish from noise.
Cheng was surprised by the extent to which losing data maintained by the United States affected ocean heat content observations. The United States contributes more than 50% of the ocean observation data in GOOS and provides crucial observational coverage of the Arctic Ocean and the tropics. “We knew it was important, but it’s even more important than we thought,” Cheng said.
“Historically, I had been proud of how much the U.S. has contributed to the ocean observing enterprise globally,” Palevsky said. But, she added, “that’s a really risky place for us as the global ocean sciences community to have any country play such a pivotal role.”
The authors write that their results may be underestimates of how data loss will affect measurement quality because in many cases, observational equipment and data infrastructure are shared between countries, meaning a change to one country’s ability to collect observations could “propagate through the system.”
The team also tested only how a loss of observations would affect ocean heat content data. Other essential variables could fare even worse because they are already limited by having fewer observations than ocean heat content, Palevsky said.
Coordination and Collaboration
Cheng said the results indicate a need for countries to collaborate more closely to ensure long-term global coverage of ocean observations. “This should be done in a much more coordinated way,” he said. The World Meteorological Organization’s Global Telecommunication System (GTS) offers a possible model, he said. To access data from GTS, a country must also contribute data.
“Some of the U.S. contributions don’t have funding to take us all the way to having those conversations [in 2029].”
Scientists, too, could coordinate better by teaming up with each other when heading out on scientific cruises, Cheng said. He imagines a global platform scientists can use to communicate to see whether their research goals and cruise routes match up with those of scientists elsewhere in the world. The ocean observation community meets every 10 years; the next meeting will occur in Qingdao, China, in 2029. Cheng said the gathering will be a good opportunity for “everyone to sit together and create a high-level agreement about how to move forward” toward better coordination. “I think we can achieve this,” he said.
However, 2029 may come too late to address some of the uncertainty facing U.S. ocean research, Palevsky said. “Some of the U.S. contributions don’t have funding to take us all the way to having those conversations [in 2029].”
—Grace van Deelen (@gvd.bsky.social), Staff Writer
Citation: van Deelen, G. (2026), Changes in funding could tank quality of ocean heat content data,
Eos, 107, https://doi.org/10.1029/2026EO260226. Published on 13 July 2026.
Text © 2026. AGU.
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