A massive underwater wave associated with the current 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 event.
Known as the Kelvin wave, it is not an unexpected occurrence but is occurring against the backdrop of human-induced climate change that has already elevated ocean and atmospheric temperatures. A smaller wave reached British Columbia earlier this 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 natural weather event. In normal circumstances, winds blow from east to west along the equator in the Pacific Ocean, pushing water from South America towards Asia. During El Niño years, these east-to-west winds weaken or even reverse, allowing water to move eastward.
When these Kelvin waves reach the South American coast, the accumulated water has nowhere further east to go, causing it to split and travel along the coasts of the Americas and potentially reaching Canada. Sea-level data from Tofino on Vancouver Island’s Pacific coast demonstrates the impact of the earlier Kelvin wave in June.
Contrary to a giant tsunami-like wave, the Kelvin wave temporarily elevates sea levels, creating a broad but shallow bulge in the ocean’s surface by approximately a foot, as explained by University of California climate scientist Daniel Swain.
The effects of the Kelvin wave are most noticeable during king tides, especially high tides resulting from the combined gravitational pull of the sun and moon. When this sea level rise is added to a king tide and potentially a winter storm causing a storm surge, the impact can be significant, according to Merryfield.
The compounding effects of the Kelvin wave, strengthened northward winds, winter storms, climate change-induced rising sea levels, and intensified extreme weather conditions may exacerbate flooding and erosion along the coast. Previous strong El Niños have led to extensive erosion on California’s beaches.
Authorities in California are taking preventive measures by placing emergency sand on beaches, anticipating that the Kelvin wave could increase water levels by six to twelve inches. The impacts of the Kelvin wave and El Niño could extend beyond the current season, potentially making 2027 the warmest year on record due to the release of stored heat into the atmosphere during El Niños, according to Merryfield.
The implications of the Kelvin wave and El Niño may have far-reaching consequences, with the oceans absorbing excess heat from greenhouse gases and potentially leading to record-breaking warmth in the coming years, as highlighted by various climate research organizations and scientists.
