Ocean waves are getting bigger as Earth gets warm, study says

In a groundbreaking study, novel research has revealed a concerning trend — waves are surging to greater heights and surf reaching at least 13 feet (approximately 4 metres) is becoming more frequent off the coast of California.

This escalating wave height has been attributed to the warming of the planet, as evidenced by meticulous analysis of seismic records dating back to 1931, an approach devised by Oceanographer Peter Bromirski at the Scripps Institution of Oceanography.

The study stands as a testament to the profound impact of climate change on oceanic dynamics and coastal regions, reported the Associated Press.

Seismic records unveil waves' escalating stature

The methodology employed by Bromirski is distinctive in its use of seismic records to chart the transformation in wave height.

As waves crash against the shore, they generate a reverberation of energy through the seafloor, a signal captured by seismographs designed to detect seismic activity.

The intensity of this signal correlates with the height of the waves.

Conventionally, wave height data relied on buoys deployed by the National Oceanic and Atmospheric Administration (NOAA), but these records only extended back to 1980, limiting the ability to comprehensively analyse historical trends.

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Unearthing decades of data: A gruelling endeavour

To extend the timeline of investigation, Bromirski enlisted a team of undergraduate students to scrutinise seismic data spanning decades.

This painstaking endeavour involved digitising voluminous paper records, a process that unfolded over several years.

Despite its labour-intensive nature, this undertaking yielded invaluable insights into the evolution of wave heights along California's coast over nearly a century.

The results of this study were striking. Average wave heights during winter months have augmented by up to a foot since 1970, a period that coincides with the onset of accelerated global warming.

Moreover, occurrences of swells measuring at least 13 feet have doubled in frequency between 1996 and 2016, in contrast to the period from 1949 to 1969.

A notable revelation was the absence of prolonged periods of exceptionally low wave heights prior to 1970, a phenomenon that has become virtually non-existent in subsequent years.

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Implications for coastal communities 

These escalating wave patterns are not confined to the realm of statistics.

They manifest in tangible ways, with cascading consequences for coastal regions. Erosion, coastal flooding, and damage to vital infrastructure have surged, particularly when coupled with the rising sea levels attributed to climate change. Bromirski emphasised that these changes amplify the likelihood of destructive events and their frequency, contributing to a heightened risk landscape.

Oceanographer Gary Griggs, from the University of California Santa Cruz, who spoke to the Associated Press, noted that while a one-foot increase in wave height over half a century might not seem dramatic, it aligns with the broader trends seen in the world’s oceans.

(With inputs from agencies)

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