This satellite-based image shows Hurricane Katrina approaching the Gulf Coast in August 2005.
It's certainly not what officials had in mind when they curbed industrial aerosol pollutants, but a new study suggests that doing so has had a big effect on Atlantic Ocean temperatures -- and in the case of the U.S. can be linked to warming seas that fueled hurricanes like Katrina.
"When industrial pollution peaked over the Atlantic, this effect played a big role in cooling the ocean beneath," Paul Halloran, a study co-author and ocean scientist with the British government's Met Office weather service, said in a statement accompanying the study. "As pollution was cleaned up -- for example after the clean air legislation of the '90s -- the seas warmed."
Earlier studies found a link between sea temperatures, hurricanes and droughts. But the new study, published in the peer-reviewed journal Nature, goes beyond that to bring into the picture aerosols from the burning of fossil fuels. Those industrial aerosols can cause corrosive acid rain.
"Our study is the first to identify how significant these human emissions of aerosols are because they capture aerosol interactions with clouds," co-author Ben Booth told msnbc.com.
It turns out more aerosols make clouds brighter and longer lasting, thus reflecting sunlight back up and cooling seas. Less do the opposite, warming seas.
Using a computer model to track aerosol emissions, cloud impact and ocean temperatures, the researchers found that while volcanic eruptions also contribute aerosol pollution, the manmade effect has been much more significant.
If you're thinking that nations should increase manmade aerosols to battle hurricanes by cooling the Atlantic, the researchers say not so fast.
"While cool phases correspond to periods with lower hurricane activity in the North Atlantic," Booth said, "they are also linked with widespread persistent African drought (1970s and 1980s) -- with all the associated food and mortality related impacts."
"I think this is a very important point that we need to get across when we communicate these results," he added.
Other studies have shown that droughts in Africa and even South America are tied to changes in ocean temperature, Booth said.
"Our study focuses on how we understand these changes, previously thought to be natural oscillations," he added, and it suggests "that much of this could have been driven by human emissions and volcanic events."
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