US ocean-sensor cuts could weaken El Niño and AMOC monitoring

Scientists warn of a blind spot forming at sea

Funding cuts to the Ocean Observatories Initiative, or OOI, are set to remove most of a network of ocean-sensing moorings that scientists say has become critical for tracking climate and ocean changes in both the Pacific and Atlantic. Researchers interviewed by New Scientist argue that the rollback will hinder monitoring of El Niño, reduce the quality of weather forecasting, and weaken efforts to watch for changes in the Atlantic Meridional Overturning Circulation, or AMOC.

The OOI consists of five mooring arrays off the US west and east coasts and near Greenland. In 2023, the US National Science Foundation described the program as necessary for monitoring “critical organs of the Earth” and announced $220 million in funding. But last month, according to the report, the NSF said the arrays would be largely removed from the water following funding cuts by the Trump administration.

What the network has already done

The article grounds the warning in concrete examples. In 2013 and 2014, as the jet stream shifted north, a mass of unusually warm water known as “the blob” spread across a vast swath of the north Pacific. OOI instruments moored off Alaska, Washington, and Oregon alerted scientists and the fishing industry to the arrival of water that was as much as 4 degrees Celsius hotter than normal.

During the El Niño phase of 2015 and 2016, sensors attached to OOI mooring wires showed that the blob was expanding into the deep sea below 250 meters. Those data helped demonstrate that the event fueled toxic algal blooms that shut California’s $60 million Dungeness crab fishery for the season.

These examples matter because they show the network’s value not only for academic climate science, but for commercial planning and regional risk management. Ocean change is not an abstract future issue when fisheries, drought patterns, and marine ecosystems are affected in real time.

Why removal matters now

The loss of most OOI moorings comes at a moment when scientists are already watching for an imminent El Niño and continuing to assess the stability of Atlantic circulation. The source says the cuts will diminish the accuracy of weather forecasting, including precipitation patterns linked to drought in the western United States. They will also hinder monitoring of any weakening in the AMOC, a system that helps keep Europe temperate.

That combination of impacts makes the decision unusually consequential. The moorings do not simply produce archival environmental data. They inform forecasts and help interpret fast-changing conditions that can influence fisheries, water planning, and regional economic activity.

The economics of cutting observation

One of the strongest arguments in the article is financial rather than purely scientific. The OOI costs about $56 million a year to operate. By contrast, the US commercial fishing industry generates billions of dollars annually, and weather and climate disasters caused $183 billion in damage in 2024, according to the final federal tally before the government stopped maintaining it in 2025.

John Abraham of the University of St. Thomas put the issue bluntly in the article: “We’re flying blind, and it will end up costing us more.” That captures the core policy tradeoff. Observation programs can look expensive in budget documents, but the cost of not seeing large-scale ocean changes clearly may be higher when communities and industries have less time to prepare.

A climate capability that is hard to rebuild

Ocean-observing systems also have a practical vulnerability: once they are removed, expertise, maintenance rhythms, and data continuity are difficult to restore. A gap in long-running measurements can reduce the value of future datasets because trends become harder to compare across time.

That is especially important for phenomena like AMOC variability and marine heat events, where long records are often necessary to distinguish background noise from structural change. Cutting the network now risks losing more than hardware in the water. It risks interrupting the continuity needed to understand whether the ocean is entering a new regime.

• The NSF said most OOI moorings will be removed following funding cuts.
• Scientists say the move will weaken monitoring of El Niño, marine heat events, and AMOC changes.
• OOI data previously helped track the Pacific “blob” and related harmful algal blooms.
• Researchers argue the savings could be outweighed by damage to forecasting and resource planning.

The warning from scientists is therefore not just that less data will be collected. It is that the US may lose a strategically important early-warning capability at a time when ocean-driven climate and weather risks are becoming more economically and politically significant.

This article is based on reporting by New Scientist. Read the original article.