A massive underwater wave related to this year’s El Niño weather phenomenon is making its way along the western coast of the Americas, sparking concerns among scientists over how climate change is amplifying the effects of this natural event. Known as the Kelvin wave, this occurrence is not unexpected but is occurring against the backdrop of human-induced climate change, which has already heated up the oceans and atmosphere.
Earlier this summer, a smaller wave reached British Columbia, and another wave is anticipated to arrive within one to two weeks, as stated by Bill Merryfield, a research scientist at Environment and Climate Change Canada. Observations in June showed sea levels rose by over 30 centimeters in certain locations, and it is anticipated that the upcoming wave will be even more robust.
The Kelvin wave, like El Niño itself, is a naturally occurring weather event. In typical years, winds travel from east to west along the equator in the Pacific Ocean, pushing water from South America towards Asia. However, during El Niño years, these east-to-west winds weaken or change direction, allowing water to move eastward instead.
When these Kelvin waves hit the South American coast, the water accumulation splits and flows along the coasts of the Americas, eventually reaching Canada. The impact of the previous Kelvin wave in June was evident in sea-level monitoring data collected at Tofino on Vancouver Island.
Unlike a massive tsunami-like wave, the Kelvin wave causes a temporary elevation in sea levels. Described as a broad, shallow bulge spanning hundreds of miles, it raises the ocean surface by about a foot, as explained by University of California climate scientist Daniel Swain.
The effects of the Kelvin wave are most noticeable during king tides, particularly when high tides coincide with gravitational forces from the sun and moon, resulting in higher-than-usual tides. When this sea level rise from El Niño combines with king tides and potential storm surges, the consequences can be severe, according to Merryfield.
The compounding impacts of the Kelvin wave, intensified northward winds, winter storms, climate change-induced sea level rise, and extreme weather patterns could exacerbate flooding and erosion along the coast. Past strong El Niños have caused extensive erosion on California’s beaches, leading local authorities to take emergency measures and anticipate a rise in water levels of six to twelve inches due to the Kelvin wave.
Merryfield cautioned that the effects of the Kelvin wave and El Niño could extend beyond the current season. During El Niños, some of the stored heat in the oceans is released into the atmosphere, potentially leading to 2027 being recorded as the warmest year on record by a significant margin, based on predictions from various climate research organizations and scientists.