A massive underwater wave associated with this year’s El Niño weather pattern is making its way along the western coast of the Americas, sparking concerns among scientists about how climate change is amplifying the effects of this naturally occurring event.
Known as the Kelvin wave, this phenomenon is not unexpected. However, occurring against the backdrop of human-induced climate change, which has already heated up the oceans and atmosphere, it raises additional worries.
A preliminary wave reached British Columbia earlier this summer, with another one anticipated to arrive within the next one to two weeks, as outlined by Bill Merryfield, a research scientist at Environment and Climate Change Canada.
Observations in June revealed sea level increases exceeding 30 centimeters in some areas, with expectations of a more robust wave in the upcoming event.
The Kelvin wave, similar to El Niño itself, is a natural weather occurrence. In regular conditions, winds blow east to west along the Pacific Ocean’s equator, pushing water from South America towards Asia. However, during El Niño years, these east-to-west winds weaken or reverse, enabling water to move eastward.
As these Kelvin waves hit the South American coast, they disperse and travel along the Americas’ coasts, eventually reaching Canada. Sea-level measurements from Tofino on Vancouver Island displayed the impact of the previous Kelvin wave in June.
Rather than a towering tsunami-like wave, the Kelvin wave causes a temporary elevation in sea levels, akin to a broad, shallow bulge spanning hundreds of miles and raising the ocean’s surface by about a foot.
Merryfield highlighted that the most noticeable effects occur during king tides, particularly when these coincide with a surge in sea levels from the Kelvin wave, potentially aggravated by winter storms. The combined impacts could lead to heightened flooding and erosion along the coast.
In anticipation of the Kelvin wave’s effects, authorities in California are taking preventive measures, expecting water levels to rise by six to 12 inches. Past strong El Niños have caused significant erosion on California’s beaches.
Merryfield cautioned that the repercussions of the Kelvin wave and El Niño could extend beyond the current season. During El Niños, the oceans release stored heat into the atmosphere, potentially setting the stage for 2027 to be the warmest year on record by a significant margin, aligning with warnings from various climate research bodies and scientists.