A Florida State University led analysis is throwing cold water on the idea that the Atlantic just warms and cools on its own schedule. The study finds that long term swings in Atlantic sea surface temperatures are largely driven by human influence, not simply natural ups and downs. That is a big deal for South Florida, where warmer Atlantic waters act as high octane fuel for stronger, faster intensifying hurricanes, and where the Gulf of Mexico has recently seen a clear uptick in ocean heat content. The authors and local oceanographers say the pattern, a mix of greenhouse gas warming and changing aerosol pollution, is reshaping how scientists think about seasonal storm risk.
What the study did
The paper, published in Geophysical Research Letters, used a new method called Rotated Low Frequency Component Analysis on large ensemble climate model simulations and observational sea surface temperature records. The goal was to tease apart externally forced changes from internal climate variability. Across multiple model families, the team found that the Atlantic Multidecadal Variability is mostly explained by external forcing, while similar decadal scale swings in the Pacific appear to come mainly from internal variability within the climate system.
FSU authors call the finding actionable
Lead author Michael Diamond, an assistant professor of meteorology at Florida State University, told the Miami Herald that "humans are the driving force behind the warming and cooling of the Atlantic." He added that the result can be read as a kind of good news, since it suggests that policy decisions and emissions choices have the power to alter ocean conditions over multidecadal periods, rather than leaving coastal regions at the mercy of random long term swings.
Why deeper ocean heat matters for storms
University of Miami oceanographer Nick Shay, also speaking to the Miami Herald, cautioned that sea surface temperatures are "basically skin deep" and that the real gauge of hurricane fuel is ocean heat content below the surface. NOAA products built from satellites and altimeters show that the upper ocean has soaked up most of the excess heat in recent decades, which helps explain why parts of the Gulf of Mexico have been trending warmer (NOAA CoastWatch).
Cleaner air had an unexpected effect
The FSU team highlights that two overlapping human influences, rising greenhouse gas concentrations and shifts in aerosol pollution, can create what look like alternating periods of cooling and warming at the surface. Earlier work led by NOAA scientist Hiroyuki Murakami found that declines in anthropogenic aerosols over North America and Europe helped boost Atlantic tropical cyclone activity, a mechanism described in a Science Advances paper.
Takeaway for South Florida
For residents and planners, the message is blunt: Atlantic temperature swings are not just random weather luck; they are shaped by human emissions and air quality trends, and that influences hurricane risk. The Geophysical Research Letters study argues that correctly separating forced signals from internal variability improves prediction and gives policymakers a clearer view of how mitigation and adaptation choices today can alter the odds of future storms.
