A massive underwater wave associated with this year’s El Niño weather phenomenon 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 natural occurrence.
Known as the Kelvin wave, this event is not surprising. However, occurring against the backdrop of human-induced climate change, which has already heated up the oceans and atmosphere, it is causing heightened worry in scientific circles.
A smaller wave reached British Columbia earlier this summer, and another is anticipated to arrive within the next one to two weeks, as indicated by Bill Merryfield, a research scientist at Environment and Climate Change Canada.
Merryfield noted, “We already observed sea level rises of over 30 centimeters in some areas in June. The upcoming wave appears to be even stronger.”
The Kelvin wave, like El Niño itself, is a naturally occurring weather pattern. In regular years, easterly winds blow across the equator in the Pacific Ocean, pushing water from South America towards Asia. However, during El Niño years, these winds weaken or change direction, enabling water to move eastward instead.
When these Kelvin waves reach the South American coast, they encounter a barrier, causing the water to split and flow along the coasts of the Americas, eventually reaching Canada.
Data from sea-level monitoring at Tofino on Vancouver Island’s Pacific coast reflects the impact of the previous Kelvin wave in June. Rather than creating a massive tsunami-like wave, the Kelvin wave temporarily elevates sea levels.
Describing it as a broad, shallow bulge extending hundreds of miles across the ocean’s surface by about a foot, University of California climate scientist Daniel Swain likened the effect to a gentle swell.
Merryfield highlighted that the most significant impacts are felt during king tides, especially when combined with sea level rises caused by El Niño and potential storm surges during winter.
The compounding effects of the Kelvin wave, intensified northward winds, and winter storms, along with the ongoing climate change-induced sea level rise and extreme weather patterns, could exacerbate coastal flooding and erosion. Previous strong El Niños have caused widespread erosion on California’s beaches.
Local authorities in California are taking proactive measures by adding emergency sand to beaches in anticipation of the Kelvin wave raising water levels by six to twelve inches.
Merryfield cautioned that the implications of the Kelvin wave, and El Niño in general, could extend beyond this season. During El Niños, some of the excess heat stored in the oceans from greenhouse gases is released into the atmosphere, potentially leading to 2027 being recorded as the warmest year on record. Similar warnings have been issued by various climate research organizations and scientists.