Shell Beach, the Rise of the Ocean and Climate Change

The beach stretches a quarter of a mile from the shore.  It is sparkling white and gives easily underfoot, but it is not sand, you are walking only on tiny shells.  As you approach the shore the crystalline clarity of the water reveals the same brilliant white shells below the surface.  The breeze is cool; the peace is palpable.  This is Shell Beach on Shark Bay in Western Australia.  It is one of only two such places in the world.  

            When you stand on Shell Beach you are standing on some 30 feet of cockle shells.  Cockles are small, edible, saltwater clams.  In this particular area, the Indian Ocean regularly floods the pan, evaporates slowly, and leaves the water much saltier than the open ocean.  These particular cockles thrive in the same water that is too salty for their predators.  Having nothing to eat them, they flourish, completely taking over the bay and its beach.  The shells pile up so deeply that, given time and pressure, they form the type of limestone known as Coquina.

            The timeline for the beach started 10,000 years ago at the end of the last of the Earth’s great Ice Ages.  At that time there was so much water locked up in ice that the oceans were lower.  Facing a water-starved Indian Ocean, the area that is now Shell beach was dry land.  As the Ice Age ended and the world warmed, the oceans rose and Shell Beach was covered with its super saline soup.  The shore line was at about the same spot it now occupies.  Then, around 4,000 years ago the oceans rose dramatically, inundating even the area that is now dry beach.  In the last 2000 years, the water has again receded to the level it occupied immediately after the last Ice Age.

            Now, every Chicken Little on the left is preaching the horrible things that we (meaning Americans, capitalists, Republicans, meat-eaters…name the group you love to hate) are doing to this planet to make the oceans rise.  Well, it seems the oceans did that all on their own, and quite effectively, 4000 years ago.  In the 1600’s we humans weren’t doing much to pollute the air beyond simple flatulence.  So what was happening?

            Actually, the facts produce more questions than answers.  We know that around the middle of the 17th century the earth’s climate was influenced by the Maunder Minimum, a period of greatly reduced sun spot activity.  That same period saw an absence of solar magnetic activity accompanied by a reduction in the radiative output from the Sun.  Coinciding with the Maunder Minimum, three excessively cold periods called the Little Ice Age occurred.  Also during this time, the planet cooled by greater amounts than it is now warming.  Since then, as the radiation from the sun has increased, so has the temperature on Earth.   There is also new evidence from studies in Antarctica that the Little Ice Age, long thought to be primarily a Northern Hemisphere phenomenon actually started at the South Pole. 

            How does a cooling period increase sea levels, as it did at Shell Beach 4000 years ago?  How does cooling in the Southern Hemisphere transfer effect to the Northern?  And how does all of this happen without human intervention?  Evidently we aren’t as important in the grand scheme of things as we thought.  The Earth cools and heats.  It happens slowly.  If we accept our climate as a spontaneously occurring event and stop using it to create politically convenient targets we might be able to plan in accordance with need.  

            Seek out facts, not blame, and keep the faith.