A substantial underwater wave linked to this year’s El Niño weather phenomenon is making its way up 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 unexpected but is occurring against the backdrop of human-induced climate change that has already heated up the oceans and atmosphere. A previous smaller wave hit British Columbia earlier in the summer, and another wave is anticipated to arrive within the next one to two weeks, as confirmed by Bill Merryfield, a research scientist at Environment and Climate Change Canada.
The Kelvin wave, like El Niño itself, is a naturally occurring weather event. In regular circumstances, winds blow from east to west along the equator in the Pacific Ocean, driving water from South America towards Asia. During El Niño years, these east-to-west winds weaken or change direction, allowing 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 up and down the coasts of the Americas and eventually reaching Canada. Sea-level data collected in Tofino on Vancouver Island’s Pacific coast illustrates the impact of the earlier Kelvin wave in June.
Rather than creating a massive tsunami-like wave, the Kelvin wave temporarily elevates sea levels. According to University of California climate scientist Daniel Swain, it creates a broad, shallow bulge in the ocean surface over hundreds of miles, raising the height by about a foot.
Merryfield highlighted that the effects of the wave are most noticeable during king tides, especially high tides resulting from a combination of the gravitational forces of the sun and moon. When this sea-level rise coincides with a king tide and a winter storm-induced storm surge, the impact can be significant.
El Niño’s effects, such as strengthening northward winds along the coast, could further elevate sea levels along the British Columbia coast. This, combined with the Kelvin wave, intensified northward winds, winter storms, and the ongoing impact of climate change on rising sea levels and extreme weather, may exacerbate flooding and erosion along the coastline. Past strong El Niños have caused widespread erosion on California’s beaches.
Authorities in California are taking preemptive measures, such as placing emergency sand on beaches, in anticipation of the Kelvin wave raising water levels by six to twelve inches. Merryfield cautioned that the impacts 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 the warmest year on record by a significant margin.
The implications of the Kelvin wave and El Niño could have far-reaching effects, as warned by Merryfield, as the oceans release stored heat due to greenhouse gas emissions, potentially making 2027 a record-breaking year in terms of warmth.