A massive underwater wave linked to the current El Niño weather phenomenon is making its way along the western coast 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 surprising. However, it is occurring in the context of human-induced climate change, which has already heated up the oceans and atmosphere.
A smaller Kelvin wave reached British Columbia earlier this summer, and another one is anticipated to arrive within the next one to two weeks, as stated by Bill Merryfield, a research scientist at Environment and Climate Change Canada. Merryfield noted that a previous wave brought sea level rises of over 30 centimeters in some areas in June, and the upcoming wave is expected to be even more potent.
The Kelvin wave, like El Niño, is a naturally recurring weather phenomenon. During normal years, winds blow from east to west across the equator in the Pacific Ocean, displacing water from South America towards Asia. In El Niño years, these easterly winds weaken or reverse, allowing water to move eastward. When these Kelvin waves hit the South American coast, the water accumulates and redistributes along the Americas’ coasts, eventually reaching as far as Canada.
Sea-level data from Tofino on Vancouver Island’s Pacific coast illustrates the impact of the earlier Kelvin wave in June. Rather than a towering tsunami-like wave, the Kelvin wave causes a temporary increase in sea levels, resembling a broad, shallow bulge spanning hundreds of miles in ocean surface height.
The effects of the Kelvin wave are most pronounced during king tides, especially when combined with winter storms, resulting in elevated sea levels that can lead to significant problems. The compounding impacts of the Kelvin wave, intensified northward winds, winter storms, and ongoing climate change, which is already elevating sea levels and exacerbating extreme weather events, may exacerbate flooding and erosion along the coastlines.
Merryfield cautioned that the ramifications of the Kelvin wave and El Niño may extend beyond the current season. During El Niño events, some of the excess heat stored in the oceans due to greenhouse gas emissions is released into the atmosphere, which could contribute to 2027 becoming the hottest year on record by a substantial margin. Similar warnings have been echoed by various climate research organizations and scientists.
The Kelvin wave and its broader implications highlight the complex interplay between natural phenomena and human-induced climate change, underscoring the importance of understanding and addressing these interconnected challenges.
