Geologist Gary Griggs wants to take you on a tour of our evolving coast
Should Californians worry about tsunamis? Why do we need coastal fog? Are you living on an ancient sea floor? The answers to these questions and more can be found in “Introduction to California’s Beaches and Coast” by Gary Griggs, director of the Institute of Marine Sciences and Long Marine Laboratory at UC Santa Cruz. Published last year by the University of California Press as part of their California Natural History Guides series, the book is a pocket-sized easy read, designed for the layperson, naturalist or anyone with a curiosity about the natural world.
If anyone knows about the forces that have shaped California’s coastline, it’s Griggs. A trained geologist, he has studied the coast for the past 40 years, taught courses in coastal geology and oceanography, and leads natural history walks along the Monterey Bay. He writes a column for the Santa Cruz Sentinel called “Our Ocean Backyard,” and has co-authored “Living with the Changing California Coast” and “The Santa Cruz Coast: Then and Now.”
Griggs’ expertise makes him an ideal candidate to lead the next event in Bookshop Santa Cruz’s Outdoors series: Coastal Hike and History with Gary Griggs. The two-hour guided hike will take place at 2 p.m. on Saturday, June 25 on West Cliff Drive.
“We live in such a beautiful place; we wanted to find a way to connect books and literature to the outdoors,” says Casey Coonerty Protti, owner of Bookshop Santa Cruz, which has hosted the series for three years. Past authors have included mystery writer Laurie King, artist Tom Killion and poet Ellen Bass.
“Most of our outdoor events have been in the mountains and redwoods,” says Protti. “We really wanted to connect people with the ocean.”
It was this same desire to connect people with the ocean—and the forces that shape our ever-changing coastline—that inspired Griggs to write “Introduction to California’s Beaches and Coast.”
“So many people in California live on the coast and (face) conflicts of land use, coastal erosion and water quality,” says Griggs. “The ocean is a thread in the background, trying to push onto the land—and we try to push it back. After writing my column for the Sentinel and all the talks I’ve given, I realized how much information people would like to have. It was a labor of love in some ways.”
Rather than an academic tone, the book has a conversational cadence that is inviting to the curious mind. Griggs teaches the reader to look at patterns on the coastline—such as ripples, scarps and fossil traces—to reconstruct the story of how the landscape was formed. Though some of the topics may seem frightening (rising sea levels, disappearing beaches and the hazards of oceanfront living), the book arms the reader with knowledge to better understand these conflicts.
From a geological perspective, one thing’s for sure: the California coastline is just a temporary line drawn in the sand.
“What we call the coastline today happens to be where it is in 2011,” Griggs says. “Natural Bridges used to have three bridges, now there is just one. The arch that used to be at Steamers Lane has disappeared. Over the last 100 years, it’s pretty striking to see the changes (that have occurred).”
Though many changes occurred during El Niño, with high tides and large winter storms, Griggs cautions that as sea levels rise due to global warming, Santa Cruz’s coastline will change at a rapid pace.
“The thing that is hard to grasp for a lot of people is that climate change didn’t start in 1900; it’s been there throughout the history of the earth,” explains Griggs. “The thing that’s driving that is the amount of heat we get from the sun, which has to do with the earth’s cycle and orbit. The earth has long periods of warming and long periods of cooling.”
He paints a picture of a much different coast 18,000 years ago, when the last ice age was coming to an end: with 11 million cubic miles of sea ice sitting on land, the sea level was 350-400 feet lower than its present level.
“You could have walked off the current coast of Santa Cruz ten miles and still been on land,” says Griggs. As sea levels rose gradually over the last 10,000 years, the coastline advanced higher onto land—but this didn’t pose a problem to native coastal dwellers.
“Native people didn’t have hotels or malls; they just migrated,” says Griggs. “Today, most of the world’s major cities are along the coastline, with 150 million people living within three feet of sea level.”
Not only is California’s coastline more developed now than ever before, but due to global warming from fossil fuel emissions, sea levels are rising at a rate unprecedented in human history.
Griggs is involved in a National Academy of Sciences committee that is working on a West Coast response to climate change. He’s also actively involved with the City of Santa Cruz, devising a local plan for adapting to rising sea levels.
“Over the last 100 years, California on average has seen about eight inches of sea level rise,” says Griggs. “We’re trying to figure out what is going to happen over the long run.”
The NAS committee has extrapolated data for three different timelines: 2030, 2050 and 2100. They’ve estimated that the sea level will rise eight inches in California by 2030—as much as it has risen over the last century. By 2050, it’s estimated that sea levels will rise 18-24 inches. By 2100, sea levels are predicted to rise approximately four to five feet.
How will the rise affect Santa Cruz? Griggs says the biggest effects will occur where waves are currently eroding landforms, such as Opal Cliffs and Depot Hill. Low-lying areas where the beach is backed by a fixed structure are also at risk, because if the beach can’t move inland it will be drowned by the ocean. Griggs also predicts that sea water will move into the San Lorenzo River mouth and flood laterally.
“All these changes have been gradual; that’s why some people don’t think about it,” says Griggs. “But every city in California is starting to think about it—how to deal with sea level rise, risks, and options to respond. Rather than putting it aside, the best thing is to deal with it and be prepared.”
Bookshop Santa Cruz’s “Coastal Hike and History with Gary Griggs” will take place from 2-4 p.m. on Saturday, June 25 on West Cliff Drive in Santa Cruz. Space is limited and pre-registration is required. Individual tickets are $30 and include a book, hike and snack (Couples rate $45). 423-0900.