Apocalyptic Planet-Part Four: Seas Rise

As I write this title, it seems a bit counter intuitive that one of the first things I saw this morning was a newspaper discussing many small cities around the Texas Panhandle which are running out of water.  And on the TV news as I write this, the city of Amarillo announces measures being taken to curtail water use, followed by a detailed discussion, explaining how one of these smaller towns plans to address the lack of water.  Drought expands while ice melts and seas rise.

Childs explains sea behavior by comparing it to pouring water back and forth among a bunch of pans.  Ocean behavior varies from place to place.  Louisiana has been losing seacoast at the rate of twelve meters per year and large parts of the Nigerian coastline has lost as much as thirty meters per year, one of the fastest losses on earth–erosion.  The moon causes tides twice a day changing sea levels on the average of two meters each time.  Historically most sea level changes are long term changes.  A major cause of sea level change is temperature.  Half the current sea level rise can be attributed to thermal expansion.  Water warms and spreads out.  Not only does heat expand near the sea surface, but now also expands into depths not previously affected.  Findings by two oceanographers, Purkey and Johnson, indicate an increase in ocean heat 16 per cent greater than previously thought.  Oceans are the largest reservoirs of heat on earth.  Once heated, their size makes them slow to cool.

Purkey also notes that even in the depths of the seas, waves transfer heat.  However, because of the size of the Pacific, an event that occurred forty years ago in the southern Pacific will not reach the northern Pacific for approximately those forty years.  Thus, the warming and subsequent ice melt we see in the north Pacific started in the south Pacific forty years ago.  Another scientist, Carl Wunsch, notes that earth changes remarkably without human intervention.  Nevertheless, he recommends humans do something to reduce carbon dioxide emissions as a precautionary measure in addition to discouraging people from settling in low lying areas.  Unfortunately, rising seas do not bode well for much of the earth’s population who live in exactly these low lying areas:  all of Bangladesh, Venice, Shanghai, New Orleans, Bangkok, the Marshall Islands, and many US coastal cities to name just a few places.

St. Lawrence Island north of the Aleutians provides a perfect example of what is happening.  Sea ice breaks up too early, fish species they used to see are gone replaced by new ones they never saw before, and the population of seals and sea lions has altered.  Cancer rates in the villages there have risen dramatically caused in part by the toxic poisons concentrated in the meat of the seals, whales, and salmon they harvest from our polluted oceans.  In 2008, they brought a lawsuit against Exxon, Chevron, and Mobil, claiming that these companies are the world’s major contributors to global warming.  They want these companies to pay for moving their villages to higher ground.  Sea rise necessitates the move.  They lost in District Court, but the case is under appeal.  The court cited that the chain of events causing their predicament is too long to lay blame in one place.  Childs notes that we really need such places to endure, places where people know how to lead minimalist lives, places where people know how to survive.

Apocalyptic Planet–Part Three: Ice Collapses

It may be difficult for some to believe, but over the last three million years ice dominated earth’s climate. We remain in that long ice age; widespread glaciers still exist.  For most of earth’s long, long existence no ice existed anywhere.  Currently, we are in an interglacial period in which ice has retreated back to the poles and the highest mountain reaches.  Earth as we know it has been shaped primarily by ice and to a lesser extent by volcanoes.  Once ice lay hundreds of feet deep as far south as Chicago and London.  What caused this see saw between Ice Ages and warm, wet periods where the ice retreated or disappeared entirely?  The changing tilt of the earth’s axis. Currently, the earth’s tilt is 23.5 degrees or so.  This tilt causes the seasons in non tropical areas.  Earth’s tilt changes a degree or so over time, causing the alternating periods between extreme ice coverage and warm periods.  At times the change has been so great that no ice remained even on the poles.  Usually, these changes are very slow, over thousands of years.  No longer.

Equatorial glaciers once common in the high equatorial mountains, e.g. Andes, Himalayas, a century ago no longer exist.  Ernest Hemingway once described the glacier on Kilimanjaro as “wide as all the world”.  Now nothing but a few patches of hard snow remain.  The once giant ice fields in northern Patagonia in Chili and Argentina currently lose volume at an ever accelerating rate.  While hiking and kayaking with a filming crew in this area, Childs saw just how rapidly this ice loss occurs.  In one instance a huge ice lake run off from one glacier totally disappeared in two weeks.  In Greenland an iceberg four times the size of Manhattan floated off in 2010 and finally melted in the Gulf Stream.  It narrowly missed shipping lanes and offshore oil wells.  The Larsen B ice shelf in Antarctica the size of Yosemite National Park and 700 feet deep had been stable for more than 12,000 years.  It started coming apart over a decade ago.  It eventually floated off and melted.

Why does any of this matter?  Ice keeps the planet cooler.  Solar radiation bounces off into space.  Currently, ice reflects approximately 30 per cent of incoming sunlight.  Few present animals and people are prepared for the hothouse that would exist if much more ice melts.  This is in spite of the fact that radiation from the sun has actually gone down in the last fifty years.  As the planet warms, more ice melts, more heat remains on earth, more ice melts and the cycle continues.  The current acceleration of ice loss causes many scientists to question:  where is the tipping point?  How can we stop this rapidly accelerating ice loss?

Humans are increasing carbon dioxide levels ten thousand times faster than they changed over the last 65 million years.  Our globe is warming; all climatologists agree.  At what point will it be too late to turn this around?  Indeed, can we turn this around?  And if we do, will some of the ice return?  No one knows.  Nothing like this has occurred before in human history.  All this melting ice causes sea rise.  At the current rate a one meter sea rise by the end of this century is plausible.  Many of the world’s largest cities already have a sea level problem e.g.Bangkok.  Furthermore, the water supply for much of southern and southeast Asia depends on water from rivers and glaciers in the Himalayas.  The world’s largest supply of fresh water depends on this system.  Are we ready for a hotter, drier earth?