Researchers tracking the size of waves in the Pacific Ocean over nearly a century say they are getting bigger because of climate change. While this might sound like a surfer’s dream, there could be catastrophic implications for flooding along the Pacific Northwest coastline.
A study from UC San Diego Scripps Institution of Oceanography researcher emeritus Peter Bromirski, published in the Journal of Geophysical Research-Oceans, used seismic records dating to 1931 to determine wave height.
The results add to a growing body of scientific research that suggests storm activity in the North Pacific Ocean has increased under climate change. For example, a 2000 study tied an increase in wave height in the North Atlantic to global warming.
The study says if climate change accelerates, wave heights could have significant implications for flooding and erosion along California’s coast, which is already threatened by sea level rise — something a UBC oceanographer says could also happen in B.C.
Peter Sutherland, adjunct professor at UBC’s Department of Earth, Ocean and Atmospheric Sciences, says communities along the coastline on Vancouver Island or Haida Gwaii, for example, may need to prepare for much larger storm waves in the winter.
Sutherland, also a research scientist at the Institut Français de Recherche, said unlike California’s sandy coastline, Vancouver Island’s rocky shore may help slow erosion. He said similar research has shown that waves in B.C. have increased by about a centimetre a year since 1985.
“So that’s nearly 40 centimetres on top of a wave that might already be eight or 10 metres high,” Sutherland said.
“I think this could affect Haida Gwaii or other B.C. communities that are closer to water level,” he added. “But I don’t think it’s as severe as in California because there’s a lower population and our shorelines are typically more robust, except for some small locations.”
For the U.S. study, Bromirski had to filter out earthquakes, which are simple to detect because they are much shorter in duration than the ocean waves caused by storms, according to the UC San Diego website.
When waves reach shallow coastal waters, some of their energy is reflected back out to sea, Bromirski said. When this reflected wave energy collides with waves approaching the shoreline, it creates a signal that is converted into seismic energy that can be detected by seismographs, he said.
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