Introduction
Coastlines that separate deep ocean from dry continent are blessed with an astonishing array of moods -- angry, serene, tense, placid, explosive, confused. How could sunrise glowing upon the waters of Cape Cod Bay be any more peaceful? How could the winter waves of a frothy-mawed monster rage any more wildly against the cliffs of California's Forgotten Coast?
No other environment varies as rapidly or continuously as the coast. Waves redefine beaches second by second. Tides roll the boundary between land and sea back and forth between their fingers every day. Since the ice ages began two million years ago, sea levels around the world have risen and fallen by hundreds of feet, as if the oceans were breathing in and then out. And over hundreds of millions of years, the earth's interior has repeatedly shrugged in its sleep, crumpling up mountain ranges and displacing shorelines by many miles. Change, whether measured in seconds or millennia, is the norm for coastal environments.
For years I've reveled in an aerial view of the earth. Sometimes, flying west at sunset, it seems that the world is small and that daylight could last forever. But my flying career got off to a rocky start. It was 1972. I'd spent many evenings walking the beaches of central California, sieving sand with my fingers, pondering the waves at my feet. I was mesmerized by the ocean, seduced by its water. When I climbed a 200-foot cliff behind the beach north of Point Arguello, my imagination flew west toward the horizon. I came up with the bird-brained idea of leaping off that cliff, nominally supported by a hang glider I'd just purchased secondhand -- no questions asked, no instructions given. The first and final sortie involved multiple crashes at 40-foot intervals on my way down the cliff. I found myself lying on a beach, upside down, tangled in guy-wires, shaking with laughter at my foolishness. The beach sand felt good between my unbroken toes.
An inauspicious beginning, to be sure, but the ill-fated flight nevertheless struck a chord that continues to resonate. An earthbound bond was broken and I've never looked back. I've since learned to fly a little better, and with this book I want to share that aerial vantage point. I want to retell from the air the stories of an endlessly energetic ocean whose tides, waves, surges and storms have been shaping shorelines for billions of years.
Once there were no oceans. Four and a half billion years ago, six sextillion metric tons of meteors, comets, and assorted space debris coalesced into a sterile ball called Earth. Heat first generated by this compaction gradually dissipated while heavy minerals like iron and nickel migrated inward to form the planet's core. That initial burst of warmth would have lasted only a few tens of millions of years, but new fires of radioactive decay provided an internal source of heat that continues to this day. In the beginning, the earth was a lonely lump of molten matter with a barren surface that gradually solidified into crust. There were no shorelines because there were no oceans. No seas, no lakes, no rivers. No free water.
Then, as the crust cooled, minerals reorganized, releasing a variety of gases including hydrogen and oxygen that formed H20. Unlike our smaller neighboring planets, Earth's mass (and therefore its gravity) was sufficient to prevent solar winds from ripping away most of these nascent gases. Volcanoes belched sulphurous gusts, creating a toxic but moisture-bearing primordial atmosphere. Clouds formed and rain began to fall. Ice-ball asteroids slammed into the young earth, adding more water to puddles that grew into lakes, maybe into seas. Water was accumulating, a first step toward forming oceans and shorelines as we know them today.
