World's oceans becoming stormier, extreme waves increasing around globe: Study

The world's seas are becoming stormier, with extreme ocean winds and wave heights increasing around the globe, a study has found. Researchers from the University of Melbourne in Australia analysed wind speed and wave height measurements taken from 31 different satellites between 1985-2018, consisting of around four billion observations. The measurements were compared with more than 80 ocean buoys deployed worldwide, making it the largest and most detailed dataset of its type ever compiled.

The study, published in the journal Science, found that extreme winds in the Southern Ocean have increased by 1.5 metres per second, or 8 per cent, over the past 30 years. Extreme waves have increased by 30 centimetres, or 5 per cent, over the same period. As the world's oceans become stormier, researchers warned this has flow on effects for rising sea levels and infrastructure.

"Although increases of 5 and 8 per cent might not seem like much, if sustained into the future such changes to our climate will have major impacts," said Ian Young from University of Melbourne.

"Flooding events are caused by storm surge and associated breaking waves. The increased sea level makes these events more serious and more frequent," said Young.

"Increases in wave height, and changes in other properties such as wave direction, will further increase the probability of coastal flooding,'' he said.

Understanding changes in the Southern Ocean were important, as this was the origin for the swell that dominates the wave climate of the South Pacific, South Atlantic and Indian Oceans, researchers said. "Swells from the Southern Ocean determine the stability of beaches for much of the Southern Hemisphere," Young said.

"These changes have impacts that are felt all over the world. Storm waves can increase coastal erosion, putting costal settlements and infrastructure at risk," he said.