Our Changing Weather !

Perhaps the most important stretch of water that influences the world weather is the Great Southern Ocean between Tasmania and Antarctica.  It accounts for as much as seventy-five percent of the ocean heat sink and forty percent of the sea absorption of carbon dioxide.

Science predicts that changes to salinity may cause the ocean circulation to move in new directions and this would have a profound effect on the Southern Oceans ability to absorb heat and carbon, and change traditional weather patterns.   It could make the Australian land mass wetter - or drier  !

Teams of scientists on the Australian Research Vessel Investigator have been profiling both the temperature and salinity of the water at 108 locations.   This work includes the positioning of measuring equipment that reports the conditions at a depth of four thousand meters and delivers monthly readings.

The evidence shows that since the 1970's the bottom water - near the seabed - has become lighter and fresher.  That accelerated in 2010 and this may have been a response to the breaking off of half of the Merz Glacier Tongue in eastern Antarctica.

The latest readings show that this is changing back to becoming saltier and denser in the deepest part of the ocean, but these levels are nowhere near where they were in the 1970's - or even the 1990's. There is a distinct change in the southern ocean and this is visible to the naked eye with the contraction of seas ice cover that decreases each year.

It stands to reason that if the glaciers are melting faster they are depositing great chunks of ice formed with fresh water into the oceans and as this melts it dilutes the natural salinity.  This infusion of fresh water speeds up the circulation flow and delivers a new weather pattern.

The waters of the great Southern Ocean are important for Australia's climate but they also have a profound influence on the world weather.  Antarctic waters are also a moderator of the world climate. The oceans take up about 93 percent of the extra heat trapped in the atmosphere by greenhouse gasses and about a third of the carbon dioxide released by human activity, such as the burning of coal.

It is research carried out by vessels such as the R V Investigator that delivers information from an area with very little other human activity, and yet an area that will deeply influence the world in which we live.   We should also remember that both the polar extremities are the storehouse of this planets stock of fresh drinking water, safely stored in the form of ice and snow.

Humans in other parts of the world would be wise to have more than a passing interest in what is happening in Antarctica !