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Warming Oceans, Stronger Swells: Big Wave Surfers Ride More Powerful Waves

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A surfer rides a wave at Mavericks on Dec. 17, 2018, in Half Moon Bay, California. (Ezra Shaw/Getty Images)

For roughly three decades, Grant Washburn has looked out his window each morning and considered the height of the waves crashing against California’s ragged coastline, before dutifully noting the conditions in white, wire-bound calendars.

His meticulous record keeping of the conditions at one famous Bay Area surf break in particular — Mavericks, near Half Moon Bay, where waves can rise to the size of a four-story apartment building — has established Washburn as a sort of elder statesman and historian among local surfers.

Washburn’s surf journal documents the swell conditions and wave heights at Mavericks dating back to the early 1990s. When the monster waves are breaking, Washburn etches a drawing in his calendar.

Washburn knows more than most about the range of conditions — tide, weather and interval between peak waves — that must align perfectly for the towering blue giants to rise above the reef.

“Mavericks is an example of a place that is really specifically a measuring stick for what’s going on in the deeper Pacific, because it doesn’t break unless a certain ocean swell hits it,” he said. “And when that’s happening, it’s indisputable.”


This past December and January, Washburn drew a hell of a lot of waves .

Grant Washburn’s Surf Journals Chronicling Powerful Swells This Past Winter (Grant Washburn)

As they grew, so did the level of chatter among the surfers who ride them and have been observing larger and more powerful swells at spots like Mavericks.

Mark Sponsler, a revered surf forecaster and founder of the site stormsurf.com, has described a “golden age” for big wave surfing caused by hotter temperatures and ocean water.

As temperatures and ocean waters warm, evaporation increases, which pumps more energy into the jet stream, generating more ferocious storms over the open ocean, the genesis of Mavericks towering waves.

Bianca Valenti, a San Franciscan and one of the best big wave surfers in the world, charged at Mavericks’ monster waves more than a dozen times this past winter.

“This doesn’t feel normal,” she said recently. “It’s so crazy. It feels like a tipping point, somehow. Like how the fires this season just seemed to last for so long.”

Oceanographers from UC Santa Cruz have actually quantified in research published in the journal Nature how the energy in ocean waves has increased over a period of roughly eight decades as a consequence of climate change.

“Upper-ocean warming, a consequence of anthropogenic global warming, is changing the global wave climate, making waves stronger,” the researchers wrote.

The research team, led by Borja Reguero, coastal scientist at UC Santa Cruz, used a novel indicator for rising sea levels and climate change, using the transport of potential energy from wind to waves. (In science-speak this is called “wave power.”)

Reguero’s research shows that global annual wave power increased by an average of 0.4% per year from 1948 to 2017, with an annual rise of 2.3% since 1994.

Basically, bigger storms are creating bigger waves, and Washburn’s adding more drawings to his calendar.

Discussion of wave power, essentially wave energy, existed in the scientific literature previously, but Reguero’s group was the first to use this parameter as a way of identifying a long-term trend as a climate change effect.

Reguero’s study is especially important for California, a state that doesn’t experience hurricanes but suffers from eroding cliffs, disappearing beaches, and disrupted marine ecosystems like kelp forests, all of which are exacerbated by more powerful waves battering the coastline.

“This is really important in California, where wave action is essentially the main driver of coastal dynamics,” Reguero said.
These kinds of wind-driven waves contribute to coastal flooding, swamping beach cities like Del Mar in Southern California and Bay Area shoreline cities like East Palo Alto, transporting sediment, reshaping headlands, bays and open coastal areas.

Ocean researchers looking at satellite measurements and buoys have long known that waves, particularly in the North Pacific, were changing.

“But we now have more concrete proof that climate change is affecting global waves,” Reguero said.

Warming Could Improve Big Wave Spots. Everywhere Else? Not So Much

The impacts of climate change on California surfing is complicated, varied, and different from break to break. And in a lot of places, rising tides could actually drown out some surf breaks, while the changing direction of ocean waves might cause some swells to miss some breaks altogether.

The impact of humans could also play a part. Coastal cities might respond to rising tides by building seawalls and other protections, which could destroy the conditions in some locations.

It’s easy to guess where public officials would land if given the choice of balancing the need to protect coastal communities against the quality of a surf break or two. But the equation is more complicated for cities like Santa Cruz, with some of the best, most consistent waves in the world, a surf-crazed city that has built an identity around the sport.

Nik Strong-Cvetich, chief executive officer of Save the Waves, an organization that advocates for protecting surf ecosystems, including the local flora, fauna and surrounding communities, has been examining climate as a threat in Santa Cruz.

“Climate change is probably improving big wave spots,” Strong-Cvetich said. “But it’s overall probably deleterious for the sport of surfing in California. There are probably more spots that will be lost than improved, on the whole. Probably for surfing, it’s negative, even if it’s a little better for big wave surfing.”

Back in 2015, Dan Reineman, a surfer and environmental scientist at CSU Channel Islands, surveyed more than a thousand California surfers about the conditions that make their local breaks most optimal.

Using that information as input in sophisticated climate models, he estimated that more than a third of surf spots in California are endangered or threatened by rising sea levels, with only a small percentage improving.

“There is a really strong connection in surfing between the quality of waves, the way they break, and the depth of the water,” Reineman said. “On a day-over-day basis, the tide is what makes the biggest difference in that depth. Add climate change-driven sea level rise to that equation and everything is just going to be deeper.”

That’s a big deal in a state with millions of surfers. (Reineman’s research notes a 20-year-old California surfing census that counted 1.1 million surfers in the state.)

“Surfing waves are one of the most important resources on our coast,” Reineman said.

When Ryan Seelbach, a professional surfer from San Francisco, first started engaging with Reineman’s research and other science around climate and waves, he realized Santa Cruz could be altered by climate change.

“With that much more water pouring over the reef, it has a big impact,” he said. “I remember thinking to myself, ‘Wow, Santa Cruz is going to get heavily impacted. There’s just not too many places you can surf there at higher tide.”

A Seemingly Endless Season of Pristine Surf Days With Towering Waves

Surfing at Mavericks this winter was unbelievable with a week-after-week filled with incredible surf days, thanks in part to La Niña conditions that held a ridge of high pressure over California, deflecting storms that might normally have soaked the Bay Area to the north. Wind from the storms drove swells south directly at the Northern California coast.

On a typical year, Mavericks is surfable only a handful of days.

A notoriously fickle surf break near Half Moon Bay, the conditions at Mavericks are only good for surfing during a significant northwest swell, often generated by raging storms and winds on the other side of the world in the Northern Pacific, and mostly only during winter months.

Some years, there’s nothing. Just the open ocean. Many days, the water over the rocky reef is as tranquil as a lake.

But on good days? When the conditions are right, waves at Mavericks rise into blue monsters, well above 50 feet, some of the largest surfable waves in the world.

This past winter, surfers like Valenti and Washburn had the opportunity to surf Mavericks for dozens of days, both describing the season as one of the best of their careers.

“Mind-blowing. This is the best winter that I can remember, ever,” Valenti said.

She and other surfers of her caliber are more organized, better funded and trained, and hold a brighter spotlight than at any time in the sport’s history. Talent is peaking as swells serve up taller and more powerful sets.

It would be overstating the case to say that Valenti and her adrenaline-chasing, sun-soaked Bay Area big wave surfing colleagues are stoked about the situation. They are, after all, land-living creatures touched by climate change in all the same ways as anyone else in the region.

It’s not much fun to surf when a blanket of wildfire smoke hangs over the entire coastline of California.

But are they excited for the opportunity to surf the biggest and most powerful waves any human has ever had the courage to paddle?



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