When Hurricane Isaias approached the Gulf Coast on October 9, Climate Central released a rapid attribution analysis claiming human-caused warming had “supercharged” the Gulf waters beneath the storm and added approximately 7 mph to its winds. The claim was quickly repeated by WSMV-TV and other news outlets.
There is a problem with this increasingly common style of climate journalism. The attribution claim appeared while the hurricane was still occurring, before there was time for the sort of careful post-storm analysis normally expected when assigning causes to a complex meteorological event.
Warm ocean water is certainly necessary for hurricanes. Tropical cyclones are heat engines, drawing energy from warm water through sensible and latent heat transfer. But saying warm water fuels hurricanes is very different from claiming that an anomalously warm Gulf made a particular hurricane's winds precisely 7 mph stronger.
Meteorologist Chris Martz examined that question using two long-running National Oceanic and Atmospheric Administration (NOAA) datasets. His analysis does not prove that sea-surface warming has no influence on hurricanes, but it raises an important question about the confidence being attached to claims about individual storms.
The first distinction is simple but frequently lost in reporting: a sea-surface temperature anomaly is not the actual temperature of the water. It is the departure from an average.
The Gulf is naturally very warm during the heart of hurricane season. In late August, September, and early October, its absolute water temperatures routinely exceed the threshold necessary to sustain powerful hurricanes. A Gulf running above its climatological average therefore does not mean hurricanes suddenly have access to fuel that was previously unavailable.
Martz tested whether warmer-than-average Gulf temperatures historically corresponded to stronger Gulf hurricanes. He used NOAA's National Hurricane Center HURDAT2 hurricane database, extending back to the 19th century, and NOAA's Extended Reconstructed Sea Surface Temperature version 5 dataset.
He identified 269 tropical cyclones that reached hurricane strength while in the Gulf between 1854 and 2025. For each, he compared the storm's maximum sustained winds while in the Gulf with the average sea-surface temperature anomaly along its Gulf track.
The result was striking.
Martz calculated a Pearson correlation of just +0.036 and a correlation value (R²) of just 0.001. In that simple historical comparison, Gulf sea-surface temperature anomalies explained approximately one-tenth of one percent of the variation in maximum hurricane wind speed. The relationship between water temperature and hurricane strength was not statistically significant, not even a blip.
The wide scatter of the data is equally instructive. Some extremely powerful Gulf hurricanes occurred with sea-surface temperatures below the modern 1991-2020 average. Conversely, some hurricanes traveling across unusually warm Gulf waters remained relatively weak.
This should not be surprising. Hurricane intensity depends on much more than sea-surface temperature. Hurricane formation is a complex process.
Vertical wind shear can tear apart a developing hurricane. Dry air can disrupt convection. Atmospheric stability, upper-level outflow, storm structure, forward motion, and ocean heat content below the immediate surface all matter. Internal processes such as eyewall replacement cycles can cause substantial changes in intensity even when the surrounding environment remains favorable.
That complexity is precisely why the rush to assign a specific climate-change contribution to a hurricane while it is still making headlines should make journalists cautious.
Climate Central's analysis is model-based attribution with a false conclusion. The estimated 7 mph increase is not something that was measured by a hurricane hunter aircraft or weather buoy. There is no second Hurricane Isaias moving through an otherwise identical Gulf without anthropogenic warming against which the real storm can be compared. The counterfactual hurricane only exists in model output, not reality.
That does not make attribution modeling worthless. It does mean its results should be reported for what they are: estimates dependent upon assumptions about how the storm would have behaved in a hypothetical climate.
Martz's analysis has limitations as well. A simple historical correlation cannot isolate every variable controlling hurricane intensity, nor does it by itself disprove a thermodynamic influence from long-term ocean warming. But that is precisely the point. Hurricane intensity is a multivariable problem, which makes the media's confident reduction of a particular storm to a single climate number all the more questionable.
Instead, the attribution process increasingly seems to work backward. A damaging weather event occurs. A rapid model estimates how much worse climate change supposedly made it. The resulting number becomes a headline, and the qualification that this is a modeled counterfactual often disappears somewhere between the scientific analysis and the evening news.
There is nothing wrong with studying whether long-term climate change affects hurricanes. There is something wrong with presenting uncertain attribution estimates as though scientists had placed Hurricane Isaias on a laboratory scale and measured the additional wind supplied by carbon dioxide.
The public deserves the distinction between observation and modeling, between correlation and causation, and between what scientists know and what they estimate.
Climate attribution should follow the evidence. Increasingly, the headlines seem to be arriving well before any evidence does.
Anthony Watts ([email protected]) is a senior fellow for environment and climate at The Heartland Institute.
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