A massive underwater wave linked to this year’s El Niño weather pattern is making its way up the western coast of the Americas, causing 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 but is occurring in the context of human-induced climate change that has already heated up the oceans and atmosphere. A smaller wave reached British Columbia earlier this summer, with another expected to arrive within the next one to two weeks, as noted by Bill Merryfield, a research scientist at Environment and Climate Change Canada.
The Kelvin wave, like El Niño itself, is a naturally occurring weather phenomenon. In a typical year, winds blow from east to west along the equator in the Pacific Ocean, pushing water from South America toward Asia. However, during El Niño years, these east-to-west winds weaken or reverse, allowing water to move eastward.
When these Kelvin waves hit the South American coast, they split and travel up and down the Americas’ coastlines, eventually reaching Canada. Sea-level monitoring data from Tofino on Vancouver Island illustrates the impact of the previous Kelvin wave in June.
Rather than creating a tsunami-like surge, the Kelvin wave temporarily elevates sea levels, resulting in a broad, shallow bulge in the ocean surface. This effect could raise sea levels by about a foot, according to University of California climate scientist Daniel Swain.
The impacts of the Kelvin wave are most noticeable during king tides, especially high tides occurring when solar and lunar gravitational forces combine to produce above-average tides. When combined with the 30-centimeter sea level rise from the Kelvin wave, along with potential storm surges during winter storms, the consequences could be significant.
El Niño can also enhance northward winds, pushing more water toward the shore, further elevating sea levels along the British Columbia coast. These combined effects, including the Kelvin wave, intensified winds, and winter storms, on top of climate change-induced sea level rise and extreme weather conditions, could exacerbate flooding and erosion along the coast.
Past strong El Niños have caused widespread erosion on California’s beaches, prompting local authorities to take emergency measures such as adding sand to beaches. The Associated Press reports that the Kelvin wave could 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. During El Niños, some of the excess heat stored in the oceans due to greenhouse gas emissions is released into the atmosphere, potentially leading to 2027 being the warmest year on record by a significant margin. Other climate organizations and scientists have echoed similar warnings.
These developments underscore the complex interplay between natural weather phenomena and human-induced climate change, emphasizing the need for continued research and proactive measures to address these challenges.
