Global Warming Problems -- The Oceans

OCEAN ACIDIFICATION: While the vast majority of general interest in regards to the effects of global warming has been focused on the vagaries of weather and unsettled seasons of change; more ominous, though unfelt, changes are being ignored. The acidification of the oceans can have a much greater effect on not only the biodiversity of the seas but also to our ability to harvest their bounty to feed a hungry world.

In some regions of the oceans mussels are so dense that they obscure the bottom making harvesting relatively easy.

Everyone understands how uncomfortable a hot, sweaty day can be, but hardly anyone understands that an increase in ocean acidity will have an effect on their future well-being. The oceans cover over two-thirds of the planet's surface and provide both livelihood and sustenance for much of the world's population. Yet, for thousands of years, we have abused it as though it were a cesspool; and now we are filling it with carbon dioxide to the detriment of all of the creatures that reside beneath the waves.

Nearly 50% of all carbon dioxide produced in the past 200 years has ended up in the oceans due to the 'cleansing' action of wind and rain. The last extreme acidification of the oceans occurred some fifty-five million years ago, at which time there was a mass extinction of vast numbers of deep-sea creatures around the world. It then took well over 100,000 years for the oceans to return to their normal alkalinity.

The oceans presently have a natural alkalinity pH of about 8.2. When carbon dioxide dissolves in seawater through both wind-action and rain, it forms a weak acid that accumulates in huge volumes causing a lowering of the overall pH of the oceans. Presently the oceans' pH has dropped 0.1 since pre-industrialization levels 200 years ago. Since this is a logarithmic scale, similar to the Richter earthquake scale, a pH lowering of 0.1 equals a 30% increase in acidity. Even if carbon dioxide emissions were somehow stopped instantly, it would still take thousands of years for the oceans to neutralize the acidity and fully recover.

Marine environments, especially shell fish and coral reefs, that depend on carbonate levels are detrimentally effected. As acidity rises, carbonate levels drop, followed by coral reefs and shells dissolving; and, lastly, then their death knell. Even extremely hearty species, such as the mussel, would find such acidic conditions fatal. The risk of such catastrophic damage arising from ocean acidification can only be avoided by a dramatic decrease in the emissions of carbon dioxide.

OCEANIC CONVEYOR BELT (Thermohaline Circulation): Often referred to as the 'Oceanic Conveyor Belt', the thermohaline circulation is the global engine that drives the circulation of the seven seas. This circulation is driven by temperature-induced variances in the density of the sea water. The density of sea water is controlled by its temperature (thermal) and its salinity (haline). Cold salty water sinks while warm salty water rises. When the salinity of sea water decreases, the oceanic conveyor slows down and can actually come to a halt. This was the catastrophic concept behind the movie Day After Tomorrow -- though the cataclysmic consequences that were depicted in the movie would realistically take hundreds of years to take place, assuming no intervention took place.

The Atlantic conveyor belt transports warm and salty water from the tropics to the North Atlantic. The sea water is then cooled and sinks down into the deep ocean. This cold deep water is subsequently conveyed back southward. This thermohaline circulation is the source of the warmer sea surface temperature along the coast of western Europe and contributes to the relative mild winters Europe has experienced over the past hundred years, following the Little Ice Age.

The salinity of sea water decreases as sea ice and glaciers melt, and rivers flow down to the oceans: Fresh water reduces the overall percentage of salt in the seas. As salinity decreases so does density. Cold fresh water -- lacking the density of salt water -- will not sink; thereby stopping the engine that drives the oceanic conveyor belt. Since the warm tropic waters will stop moving north, the northern continents will begin to cool until another ice age moves down from the arctic. It is believed that European winter temperatures were as much as 10 degrees colder during oceanic conveyor belt shutdowns (such as the Little Ice Age).

RISING SEA LEVELS: While the sea levels have risen more than 390 feet since the last ice age, the oceans have been fairly constant for the past 6,000 years. Recently the world sea levels have begun rising again at a rate of 3 millimeters per year, which translates into 1 foot per 100 years. This change may be a sign of global warming. This increase in water volume is mainly due to expansion caused by an increase in water temperature. Surprisingly, only about 15% of the volume increase is attributable to melting glaciers and ice flows.

While the present-day melting of ancient glaciers and ice caps is a constant evening-news topic, it needs to be understood that if all of these ice formations melted overnight, the projected rise in sea level would be less than 2 feet. In addition, if all of the worlds ice bergs and ice shelfs -- which float on the surface of the sea -- were to melt, they would not raise sea level by any measurement since their floating mass is already factored into the observed sea levels.

Since the Greenland and Antarctic ice sheets, which contain over 95% of the world's ice, lie well above the permafrost zone, even with present day global warming factors, they cannot melt in less than several thousand years; making it highly unlikely that they will contribute in any meaningful way to the rise of sea levels in the next couple hundred years.

Another news-touted cataclysmic event is the sinking of coral islands: These hand-wringing harbingers of doom always seem to overlook the fact that these islands are made of coral; and that they exist today above sea level only because the sea level was once high enough that these coral creatures lived and thrived under the sea; and that much of the loss of coral land mass was the result of erosion during and following the devastation caused by cyclones such Gavin, Hina, and Keli.

This predictable sea level rise of one foot per century will lead to serious difficulties for poorly-planned shore-based cities such as New Orleans and Venice: These doomed cities, that already have failed storm-surge defences, will need billions more pumped in as the sea levels continue to rise over their banks in mankind's vain attempt to fight nature.

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