A massive underwater wave associated with this year’s El Niño weather event is making its way up the western coast of the Americas, sparking concerns among researchers about how climate change is amplifying the effects of this natural occurrence.
Known as the Kelvin wave, this phenomenon is not unexpected. However, it is occurring against the backdrop of human-induced climate change that has already heated up the oceans and atmosphere.
A smaller wave reached British Columbia earlier this summer, with another one projected to arrive in the next one to two weeks, as stated by Bill Merryfield, a research scientist at Environment and Climate Change Canada.
The Kelvin wave, like El Niño, is a naturally occurring weather pattern. During regular years, winds blow from east to west across the equator in the Pacific Ocean, pushing water from South America towards Asia. However, in El Niño years, these east-to-west winds weaken or reverse, allowing water to move eastward.
When these Kelvin waves hit the South American coast, the piled-up water splits and flows along the coasts of the Americas, eventually reaching Canada.
Sea-level data collected in Tofino on Vancouver Island’s Pacific coast demonstrates the impact of the earlier Kelvin wave in June. Instead of creating a tsunami-like wave, the Kelvin wave results in a temporary rise in sea levels.
According to University of California climate scientist Daniel Swain, this effect causes a broad, shallow bulge in the ocean surface, raising it by about a foot.
The consequences of the Kelvin wave are most noticeable during king tides, particularly high tides that occur due to the combined gravitational pull of the sun and moon, resulting in higher-than-normal tides.
When combined with a king tide and potential winter storms, the additional sea level rise caused by El Niño can create significant challenges, as explained by Merryfield.
Moreover, the compounding effects of the Kelvin wave, intensified northward winds, and winter storms, along with existing climate change impacts, could exacerbate flooding and erosion along the coast. Previous strong El Niños have caused extensive erosion on California’s beaches.
Authorities in California are taking preemptive measures by placing emergency sand on beaches, expecting the Kelvin wave to raise water levels by six to twelve inches.
Merryfield cautioned that the impacts of the Kelvin wave and El Niño may extend beyond the current season. During El Niños, some of the ocean’s stored heat is released into the atmosphere, potentially leading to 2027 being the warmest year on record.
Various climate research organizations and scientists have echoed similar warnings about the implications of El Niño on global warming and future climate trends.