Ocean wind speeds and wave heights are growing

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Extreme ocean winds and wave heights are increasing around the globe, with the largest rise occurring in the Southern Ocean, research shows.

Researchers from the University of Melbourne’s infrastructure engineering department, analyzed wind speed and wave height measurements taken from 31 different satellites between 1985-2018, consisting of approximately 4 billion observations.

They compared the measurements with more than 80 ocean buoys deployed worldwide, making it the largest and most detailed dataset of its type ever compiled.

“Storm waves can increase coastal erosion, putting costal settlements and infrastructure at risk.”

The researchers found that extreme winds in the Southern Ocean (also called the Antarctic Ocean) have increased by 1.5 meters (about 5 feet) per second, or 8 percent, over the past 30 years. Extreme waves have increased by 30 centimeters (about 1 foot), or 5 percent, over the same period.

As the world’s oceans become stormier, Professor Ian Young warns this has flow on effects for rising sea levels and infrastructure.

“Although increases of 5 and 8 percent might not seem like much, if sustained into the future such changes to our climate will have major impacts,” Young explains. “Flooding events are caused by storm surge and associated breaking waves. The increased sea level makes these events more serious and more frequent.

“Increases in wave height, and changes in other properties such as wave direction, will further increase the probability of coastal flooding.”

Young says understanding changes in the Southern Ocean are important, as this is the origin for the swell that dominates the wave climate of the South Pacific, South Atlantic, and Indian Oceans.

“Swells from the Southern Ocean determine the stability of beaches for much of the Southern Hemisphere,” Young says. “These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting costal settlements and infrastructure at risk.”

Researchers around the world are now working to develop the next generation of global climate models to project changes in winds and waves over the next 100 years.

“We need a better understanding of how much of this change is due to long-term climate change, and how much is due to multi-decadal fluctuations, or cycles,” Young adds.

The research appears in Science. Young and coauthor Agustinus Ribal also explain the work here.

Source: University of Melbourne