Hot tub sales would have been dismal back in the dinosaur era, when the steaming ocean provided a free alternative.
In fact, in some places it was too hot to dip a toe.
A new study of ancient sediments and fossils indicates tropical Atlantic water ranged from 91 to 107 degrees Fahrenheit between 100 million and 84 million years ago. The same region today is typically 75 to 82 degrees.
Hot tubs get very uncomfortable for most people above about 104 degrees.
"These temperatures are off the charts from what we've seen before," said Karen Bice, a paleoclimatologist at Woods Hole Oceanographic Institution.
The atmosphere had more heat-trapping carbon dioxide back then.
Bice reported the findings today at the annual meeting of the American Association for the Advancement of Science (AAAS) in St. Louis. The work will be detailed in the journal Paleoceanography.
Scientists don't know what might have caused ocean temperatures to get so high. Climate models that consider increases in carbon dioxide can't account for it, Bice said.
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