A massive underwater wave associated with this year’s El Niño weather pattern is making its way up the western coast of the Americas, causing concern among scientists over how climate change is amplifying the effects of this natural phenomenon.
Known as the Kelvin wave, this occurrence is not unexpected but is occurring against the backdrop of human-induced climate change that has already led to warming of the oceans and atmosphere. A smaller wave reached British Columbia earlier in the summer, and another one 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 naturally occurring weather event. In regular years, winds blow from east to west along the equator in the Pacific Ocean, pushing water from South America toward Asia. During El Niño years, these east-to-west winds weaken or change direction, allowing water to move eastward.
As these Kelvin waves reach the South American coast, they split and travel up and down the Americas’ coastlines, eventually reaching Canada. Monitoring data from Tofino on Vancouver Island’s Pacific coast demonstrates the impact of the previous Kelvin wave in June.
Rather than a tsunami-like wave, the Kelvin wave causes a temporary elevation in sea levels, creating a broad and shallow bulge across hundreds of miles of the ocean surface. According to University of California climate scientist Daniel Swain, this results in a rise of about a foot or so in the height of the ocean surface.
The effects of the Kelvin wave are most noticeable during king tides, especially high tides occurring when the gravitational forces of the sun and moon combine, leading to higher-than-usual tides. When combined with sea level rise due to El Niño, along with potential storm surges, these factors can significantly impact coastal regions.
The compounding impacts of the Kelvin wave, stronger northward winds, winter storms, and the effects of climate change are likely to exacerbate flooding and erosion along the coast. Previous strong El Niños have caused widespread erosion on California’s beaches, prompting emergency measures like beach sand replenishment.
Merryfield warns that the consequences of the Kelvin wave and El Niño could extend beyond the current season. During El Niños, some of the stored heat in the oceans, which helps moderate global warming, is released into the atmosphere, potentially making 2027 the warmest year on record by a substantial margin.
This projected scenario aligns with similar warnings from various climate research organizations and scientists.