A massive underwater wave associated with the current El Niño weather pattern is making its way along the western coast of the Americas, sparking concerns among scientists about the amplifying effects of climate change on this natural phenomenon.
Known as the Kelvin wave, this occurrence is not a surprise. However, it is occurring against the backdrop of human-induced climate change, which has already warmed the oceans and the atmosphere.
Earlier this summer, a smaller wave reached British Columbia, with another wave expected to arrive within the next one to two weeks, as per Bill Merryfield, a research scientist at Environment and Climate Change Canada.
Merryfield noted that some locations already experienced over 30 centimeters of sea level rise in June, indicating that the upcoming wave could be even more potent.
The Kelvin wave is a naturally recurring weather event, much like El Niño itself. In normal circumstances, Pacific Ocean winds blow from east to west along the equator, pushing water from South America toward Asia. However, during El Niño years, these winds weaken or even reverse, allowing water to move eastward.
When these Kelvin waves hit the South American coast, the accumulated water has no further eastward path, leading to its split and spread along the Americas’ coasts, eventually reaching Canada.
Sea-level monitoring data from Tofino on Vancouver Island’s Pacific coast reflects the impact of the previous Kelvin wave in June. Rather than a tsunami-like wave, the Kelvin wave causes a temporary elevation in sea levels, creating a broad, shallow bulge across a vast expanse of the ocean surface.
The effects of the Kelvin wave are most noticeable during king tides, high tides resulting from the combined gravitational pull of the sun and moon. When coupled with a winter storm-induced storm surge, the additional sea level rise from El Niño can have significant repercussions.
These effects, compounded by stronger northward winds and winter storms due to El Niño, on top of the ongoing climate change-induced sea level rise and extreme weather intensification, could exacerbate coastal flooding and erosion. Previous strong El Niños have caused extensive erosion on California’s beaches.
Authorities in California are taking preemptive measures by adding emergency sand to beaches in anticipation of water levels rising between six to twelve inches due to the Kelvin wave.
Merryfield cautioned that the impacts of the Kelvin wave and El Niño may extend beyond the current season. El Niños release stored oceanic heat into the atmosphere, potentially leading to 2027 becoming the warmest year on record by a significant margin.
Various climate research organizations and scientists have echoed similar warnings about the far-reaching consequences of the Kelvin wave and El Niño.