A large underwater wave associated with this year’s El Niño weather phenomenon is progressing along the western coastline of the Americas, sparking concerns among scientists regarding how climate change is amplifying the effects of this naturally occurring event.
Known as the Kelvin wave, this occurrence is not surprising. However, it is unfolding in the context of human-induced climate change, which has already elevated the temperatures of both the oceans and the atmosphere.
A smaller wave arrived in British Columbia earlier this summer, with another anticipated within the next one to two weeks, as noted by Bill Merryfield, a research scientist at Environment and Climate Change Canada.
Merryfield highlighted, “We observed sea level rises exceeding 30 centimeters in certain areas in June. The upcoming wave appears to be more potent.”
The Kelvin wave, like El Niño itself, is a natural meteorological phenomenon. 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, enabling water to move eastward. When these Kelvin waves reach the South American coast, the buildup of water splits and flows along the coastlines of the Americas, eventually reaching Canada.
Monitoring sea-level data from Tofino on Vancouver Island’s Pacific coast demonstrates the impact of the earlier Kelvin wave in June.
Rather than behaving like a massive tsunami, the Kelvin wave causes a temporary elevation in sea levels.
Describing it as a broad, shallow bulge extending hundreds of miles across the ocean surface, University of California climate scientist Daniel Swain explained that it raises the ocean’s height by approximately a foot.
Merryfield emphasized that the effects are most prominent during king tides, especially high tides resulting from the combined gravitational pull of the sun and moon.
When combined with the 30-centimeter sea level rise due to El Niño, potential winter storms leading to storm surges could escalate the situation, posing significant challenges.
The compounding impacts of the Kelvin wave, intensified northward winds, winter storms, climate change-induced sea level rises, and intensified extreme weather could exacerbate flooding and erosion along the coastlines. Previous strong El Niños have caused considerable erosion on California’s beaches.
Authorities in California are taking precautionary measures by adding emergency sand on beaches in anticipation of the Kelvin wave raising water levels by six to twelve inches.
Merryfield cautioned that the effects of the Kelvin wave and El Niño could extend beyond the current season. During El Niños, some of the excess heat stored by greenhouse gases in the oceans is released into the atmosphere, potentially leading to 2027 becoming the warmest year on record by a substantial margin.
This projection aligns with similar warnings from other climate research organizations and scientists.
