A massive underwater wave linked to this year’s El Niño weather phenomenon is making its way up the western coast of the Americas, prompting concerns among scientists regarding how climate change is amplifying the effects of this natural event.
Known as the Kelvin wave, this occurrence is not entirely unexpected. However, it is occurring against the backdrop of human-induced climate change, which has already heated up the oceans and atmosphere.
A smaller wave had already reached British Columbia earlier in the summer, with another wave anticipated to arrive in the next one to two weeks, as per Bill Merryfield, a research scientist at Environment and Climate Change Canada.
Merryfield mentioned, “In June, some locations experienced over 30 centimetres of sea level rise. The upcoming wave appears to be more potent.”
The Kelvin wave is a natural weather phenomenon, much like El Niño itself. In typical years, 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 change direction, allowing the water to move eastward. When these Kelvin waves hit the South American coast, they split and travel along the coasts of the Americas, eventually reaching Canada.
Data from sea-level monitoring at Tofino on Vancouver Island’s Pacific coast indicates the impact of the earlier Kelvin wave in June. Rather than a tsunami-like wave, the Kelvin wave causes a temporary increase in sea levels.
University of California climate scientist Daniel Swain described it as a broad, shallow bulge in the ocean’s surface, raising it by about a foot across hundreds of miles.
The effects of the Kelvin wave are most noticeable during king tides, particularly high tides resulting from the combined gravitational pull of the sun and moon. When coupled with a potential winter storm-induced storm surge, the additional sea level rise from El Niño could exacerbate coastal vulnerabilities.
These compounding factors, including the Kelvin wave, intensified northward winds, and winter storms, on top of climate change-induced sea level rise and extreme weather intensification, may aggravate flooding and erosion along the coast.
Past strong El Niños have caused extensive erosion on California’s beaches. Authorities there are taking preemptive measures by placing emergency sand on beaches, expecting the Kelvin wave to elevate 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. While oceans help regulate global warming by absorbing excess heat from greenhouse gases, El Niños release some of this stored heat into the atmosphere.
This phenomenon could lead to 2027 setting records as the warmest year globally. Similar warnings have been issued by various climate research organizations and scientists.