A substantial underwater wave linked to this year’s El Niño weather pattern is progressing along the western coast of the Americas, prompting concerns among scientists about how climate change is amplifying the effects of this natural phenomenon.
Known as the Kelvin wave, this occurrence is not surprising. However, it is occurring in the context of human-induced climate change, which has already led to ocean and atmospheric warming.
Earlier this summer, a smaller wave reached British Columbia, and another is anticipated to arrive in the next one to two weeks, as stated by Bill Merryfield, a research scientist at Environment and Climate Change Canada.
Merryfield highlighted that the previous wave brought sea level increases of over 30 centimeters in some areas in June. The upcoming wave is expected to be even more potent.
The Kelvin wave is a natural weather event similar to El Niño. In regular years, winds blow from east to west along the Pacific Ocean’s equator, pushing water from South America towards Asia. During El Niño years, these winds weaken or change direction, allowing water to move eastward.
When these Kelvin waves reach South America’s coast, the accumulated water splits and travels up and down the Americas’ coasts, eventually reaching Canada.
Sea-level data collected in Tofino, on Vancouver Island’s Pacific coast, demonstrates the impact of the previous Kelvin wave in June. Rather than creating a tsunami-like wave, the Kelvin wave temporarily elevates sea levels.
According to University of California climate scientist Daniel Swain, this effect is more like a broad, shallow bulge in the ocean surface, raising it by about a foot.
The impacts of the Kelvin wave are most noticeable during king tides, especially high tides resulting from the combined gravitational pull of the sun and moon. The additional sea level rise from El Niño during king tides, coupled with potential winter storms causing surges, can lead to significant challenges.
Local authorities on California’s beaches are taking emergency measures to mitigate the anticipated rise in water levels due to the Kelvin wave, expecting an increase of six to twelve inches.
The compounding effects of the Kelvin wave, intensified northward winds, winter storms, and climate change-induced sea-level rise and extreme weather could exacerbate flooding and erosion along the coast. Previous strong El Niños have caused widespread erosion on California’s beaches.
Merryfield cautioned that the impacts of the Kelvin wave and El Niño could extend beyond the current season. During El Niños, some of the excess heat stored in the oceans from greenhouse gases is released into the atmosphere, potentially making 2027 the warmest year on record by a significant margin. Similar warnings have been issued by various climate research organizations and scientists.
The potential consequences of the Kelvin wave and El Niño are significant, highlighting the need for continued monitoring and preparation for impacts on coastal regions.