Energy, Water, and Oysters on the Shell
by: Paul Kando
One could easily write several books about the relationship of energy and water. Consider this but part of one page.
photo credit: University of Florida
Apalachicola Bay is the cradle of Florida's oyster industry but, due to the shrinking supply of water from rivers that start in Georgia, the oysters are in decline. The fishery's collapse began last summer after decades of dwindling river flow. Overharvesting in the bay after the 2010 BP Gulf oil spill only worsened matters. So did persistent drought. Last year the Apalachicola River stayed at record low levels for nine months. Researchers fear the fresh water shortage may make it impossible for the bay to recover.
For generations the US had the dubious honor of being the world's greatest greenhouse gas polluter until, in 2009, China surpassed it, consuming 2,417,126,000 tons of oil equivalent and emitting 10 billion tons of atmospheric carbon, compared to the US with 2,216,324,000 tons of oil equivalent and 6 billion tons of carbon. Russia, India, Japan, Germany, Brazil, France and Canada are distant runners-up. All told, 2011 world CO2 emissions topped 34 billion tons.
But what does this have to do with oysters? - They begin life in estuaries with the right blend of saline and fresh water. And fresh water is a finite resource. The same amount is available to today's 7 billion people as there was for the 250 million that lived in Julius Caesar's days. Worldwide about 64% of precipitation evaporates, 42% of river flow runs off in floods and 19% is inaccessible. Greenhouse gas (GHG)-caused planetary warming severely impacts Earth's water cycle. Over 80% of the world's energy consumption -- 12.3 billion tons of oil-equivalent in 2010 vs. 5 billion tons in 1970 -- is of GHG emitting fossil fuels. Consequently fresh water stored in polar and glacier ice melts, more water evaporates from sea and land, only to precipitate in deluges of the kind that caused European rivers to swell, producing record-breaking floods this spring and inundated Calgary just weeks ago. Damaging amounts of water routinely fall without mitigating a growing fresh water shortage. Once glaciers melt away, rivers normally fed by slowly melting ice and snow are deprived of summer flow. Once-fertile lands gradually become deserts.
We have altered the planet's climate and chemistry, its snow cover, permafrost,
sea and glacial ice extent, and ocean volume: all fundamental elements of the
hydrological cycle. We have accelerated major processes like erosion, applied
massive quantities of nitrogen that leaks from the soil into ground and surface
waters and, sometimes, literally siphoned all water from rivers, emptying them for
human uses before they reach the ocean. We have diverted vast amounts of fresh water
to harness fossil energy, dammed major waterways and destroyed aquatic ecosystems.
These changes put us on an unsustainable trajectory
, writes Charles Vörösmarty in
the New Scientist. He is co-chair of the Global Water System Project, a research
group that hosted a recent international conference of scientists in Bonn, Germany
to assess man's impact on freshwater resources.
All but 2.5 percent of the total volume of water on Earth is saline. An estimated third of today's seven million world population already has limited access to fresh water, according to conference delegates. Mankind uses an area the size of South America to grow irrigated crops and another, the size of Africa, to raise livestock. To make this possible, forests the size of England (with their CO2-sequestering capacity) are destroyed every year. Two-thirds of major river deltas are sinking due to groundwater extraction.
Since the 1970s oceanographers have been tracking dead zones, low oxygen areas in oceans and large lakes caused by excessive, fossil-sourced nutrient pollution that deplete the oxygen supply of most marine life in near-bottom water. In 2004 there were 146 dead zones reported, each half a square mile to 27,000�square miles in size. A 2008 study counted 405 worldwide. World population is projected to reach nine billion around 2040. The majority will face severe water shortages if pollution and waste continue unabated. This self-inflicted problem is entirely avoidable, according to the Bonn conference's closing declaration.
According to UN data, Earth has about 35 million cubic kilometers of fresh water, 70% of it locked up in ice and permanent snow cover. Any melt-water that drains into the ocean becomes saline. Much of the rest is stored in groundwater aquifers accumulated over millennia which, once pumped dry, cannot be quickly replenished by rainfall. Only about 0.3% is found in lakes and rivers. Experts say some 3,800 cubic kilometers of fresh water is extracted from aquatic ecosystems around the world annually, in large part as a result of global warming. Huge amounts, including many drinking water-wells, are permanently polluted by tar-sands and shale oil extraction and fracking for natural gas. Our extractive economy abuses as much water as it uses.
A looming water crisis evokes images of emaciated desert dwellers in faraway places, not affluent Apalachicola Bay with its dwindling oyster catch. How long before the bay's diminished fresh water flow also affects Florida's other popular fish that begin life in that estuary's perfect blend of saline and fresh water -- grouper, snapper, blue crab, shrimp? How long before shortages there exacerbate overfishing - and more -- in Maine?