Strong winds are driving the ocean's biggest waves to dizzying new heights.
That's the potentially ominous finding of new research that analyzed more than 30 years' worth of global wind and wave measurements to see how they changed over time. The University of Melbourne researchers behind the work, published April 25 in the journal Science, say the supersized waves could compound the effects of rising sea levels, leading to more frequent flooding and accelerated coastal erosion.
"These changes will have impacts that are felt all over the world," Ian Young, an engineering professor at the university and a co-author of the study, said in a statement.
To study how the ocean's winds and waves have changed, Young and another researcher at the university took a close look at data collected by 31 wind- and wave-measuring satellites launched into space by NASA, the European Space Agency and other organizations. The researchers compiled 4 billion measurements collected between 1985 and 2018 and checked them against data from 80 buoys floating in oceans around the world.
The numbers paint a picture of strong winds getting stronger and big waves getting bigger — particularly in the Southern Ocean around Antarctica. Between 1985 and 2018, the fastest winds over the Southern Ocean became 8 percent faster, speeding up by about 3.4 miles per hour. Over the same time period, those winds drove the highest waves almost a foot — or five percent — higher.
Young acknowledged that the changes seemed small but said they were reason for concern nonetheless. "If sustained into the future, such changes to our climate will have major impacts," he said in the statement. The Southern Ocean sets the pace for the South Pacific, South Atlantic and Indian Oceans — and, indeed, the scientists saw small upticks in wind speed and wave height as far up as the North Atlantic.
Michael Mann, a professor of atmospheric science at Penn State University in State College, said the findings aligned with his own research on climate change's effects on the world's oceans. He said warming oceans could be making storms — and the winds associated with them — more intense.
"There is the potential for more extreme winds associated with individual storms, and greater wave heights as a result," he told NBC News MACH in an email.
Young said it was too early to decisively tie faster winds to the warming climate. He added that the increase in wind speeds could have been caused by cyclical variations in climate, such as the El Niño-Southern Oscillation, a temperature change in the Southern Pacific that occurs every two to seven years.
No matter what their cause, the amped-up winds and waves could aggravate the effects of climate change, adding destructive strength to storms already fueled by rising seas. If these powerhouses pummel the coasts, they're more likely to cause coastal flooding and erosion. Offshore, they could imperil ships and help break apart melting ice sheets.
For Mann, the results fit into a larger story of climate-related extreme weather, including droughts, heat waves and floods, all with potentially disastrous results. "More extreme weather, wind speeds and wave heights of course place greater stress on our infrastructure and pose greater threats to property and life," he said in the email.
Will ocean waves and winds continue to strengthen? No one knows for sure, but ongoing research by Young and his collaborator, University of Melbourne researcher Agustinus Ribal, might yield an answer. The scientists plan to use the 40 billion measurements they compiled to refine climate models so that they will be able to predict ocean waves going forward.
Additional reporting by David Freeman.
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