A massive underwater wave linked to the current El Niño weather phenomenon is making its way along the western shores of the Americas, sparking concerns among scientists about how climate change is amplifying the effects of this natural event.
Known as the Kelvin wave, this occurrence is not unexpected. However, occurring amidst the backdrop of global warming caused by human activities, it is compounding the impacts of El Niño. A smaller wave reached British Columbia earlier this summer, with another anticipated to arrive in the next one to two weeks, as mentioned by Bill Merryfield, a research scientist at Environment and Climate Change Canada.
The Kelvin wave, like El Niño, is a naturally recurring weather event. In normal circumstances, winds blow from east to west across the equatorial Pacific Ocean, pushing water from South America towards Asia. During El Niño years, these winds weaken or change direction, allowing water to move eastward instead.
When the Kelvin waves hit the South American coast, the water accumulates and subsequently travels along the coasts of the Americas, extending all the way up to Canada. Data from sea-level monitoring at Tofino on Vancouver Island showcased the impact of a previous Kelvin wave in June.
Contrary to a massive tsunami-like surge, the Kelvin wave temporarily elevates sea levels. Described by University of California climate scientist Daniel Swain as a broad, shallow bulge in the ocean’s surface, it can raise sea levels by approximately a foot.
The implications on the West Coast, particularly during king tides, are significant. When combined with high tides and potential winter storms, the rise in sea levels caused by El Niño can pose risks. The compounding effects of the Kelvin wave, intensified northward winds, winter storms, and climate change-induced sea-level rise may exacerbate coastal flooding and erosion.
Authorities in California are taking preemptive measures, such as placing emergency sand on beaches, in anticipation of the Kelvin wave raising water levels. The impacts of the Kelvin wave and El Niño could extend beyond the current season, with potential implications for global temperatures in the coming years.