When the waves bounce off the coast, they collide with waves coming in from the ocean and cause a wave of energy on the seabed that can be recorded by seismographs designed to detect earthquakes. The bigger the impact, the bigger the wave.
Until now, scientists have relied on a network of buoys from the National Oceanic and Atmospheric Administration (NOAA), but those data off the California coast only date back to 1980.
They found that the average size of waves in winter has grown to about 30 centimeters since 1970, when global warming is thought to have started to accelerate. Peaks of about 4 meters also occur more frequently, at least twice as often between 1996 and 2016 than between 1949 and 1969.
The study, published Tuesday in the Journal of Geophysical Research: Oceans, adds to the evidence that climate change is causing enormous changes to the world’s oceans. Other studies have shown that waves not only get bigger, they also get stronger.
The damage from strong storms and big waves is already evident. Last winter, strong storms and large surf in California caused cliffs to collapse, damaged piers and flooded part of the state’s scenic Highway 1.
Oceanographer Gary Griggs of the University of California Santa Cruz noted that while a 12-inch increase in wave height over a 50-year period isn’t huge, the findings are consistent with what scientists know about what happens. in the world’s oceans as they warm: becoming increasingly violent from more extreme storms and causing damage to coastlines.
Griggs, who was not involved in the study, said the new report adds to scientific data showing how fast the world is warming and sea levels are rising.
“We know that hurricanes are more intense and last longer, and now we have waves that are increasing in strength. All of that is consistent,” she said. “The challenge (…) is how to respond to that.”
Source: VOA
