Combining oceans and coasts with the weather and climate of Earth

Planet Earth is known as the only planet in the universe that we humans can live on. This is possible because of the surrounding oceans and how they work together with the land mass and the atmosphere (the invisible gas that surrounds the earth).

Earth is made up of four big oceanic basins (oceans), namely the Atlantic, Indian, Pacific and Southern Oceans. And when we look at the Earth from outer space, it looks like a blue circle because the oceans cover more than 70% of the earth’s surface. Oceans can also store about 97% of the earth’s water supply.

But not everyone knows what important role the oceans play in our daily lives. The oceans move salt and heat around the planet by using different mechanisms or methods.

One such important mechanism is THC or thermohaline (“thermo” refers to heat and “haline” to salt) circulation also known as the ¬Great Ocean Conveyor Belt.

The THC connects all the oceanic basins where warm tropical waters are moved towards the pole and the cooler polar waters are moved towards the equator.

A combination between the THC and flowing water on the ocean’s surface ensure that the waters are moved around to all the oceans in the world.

The role of the atmosphere and the continental masses during this movement is important.

South Africa is a maritime nation

South Africa is a maritime nation because it is surrounded by three out of the four major oceans. The Atlantic Ocean is near the West Coast, the Indian Ocean is close to the East Coast and the Southern Oceans lie further south of South Africa.

This makes South Africa a peninsula in the big oceanic environment because its mainland flows into the sea.

South Africa also owns the Prince Edward and Marion Islands in the Southern Ocean, halfway between Cape Town and Antarctica as well as a polar research base in Antartica. These three oceanic basins have different purposes on the Southern African sub-continent, particularly for South Africa.

The West, East and South Coast currents and climates

The West Coast of South Africa has dry and desert land but very productive -oceans. The oceanic movement is characterised by the Benguela water stream of the Atlantic Ocean that flows slowly northwest.

The Benguela washes out cold water along the ¬coast because an upwelling under the water brings bottom waters to the surface.

Because these surface waters are cold, not enough moisture is moved to the atmosphere to bring rain and that is why the land is dry.

The upwelling is very productive and is the cause for rich fishing grounds that benefit the fisheries on the coast.

The east coast of South Africa has the warm and fast-flowing Agulhas water stream that is close to green and lush pieces of land. Unfortunately, the fisheries on the East Coast are not as rich.

The land along the east coast is so green because the warm Agulhas waters supply moisture into the atmosphere, which in turn produces clouds that can bring rain in the summer time.

The South Coast of South Africa is a region between the west and east coast. It gets rainfall through¬out the year due to the influence of the Agulhas and Benguela water streams.

Projected scenarios for South Africa’s winter rainfall

Future predictions show that the wetter regions (East Coast) of southern Africa will become even ¬more wet, with the dry regions (West Coast) becoming drier.

When you look at when World Oceans Day (and the Soccer World Cup) is celebrated, it is important to describe future predictions for the winter (May and June) rainfall. During winter, the South Atlantic high-pressure cell is weakened by the passing eastward-moving mid-latitute cyclones that bring rain to the Western Cape and the South Coast region of South Africa. From 2030 to 2050 the Western Cape will have 5% to 30% less winter rain than it is having now and this makes the winter shorter.

This will in turn lead to droughts and affect the agriculture of the ¬region. The coastline around South Africa, from the Orange River on the West Coast, to Kosi Bay on the East Coast, is more than 3?000 km long.

These coasts pro¬vide several goods and services to the people of the continent. These coasts have not been managed properly because there are not enough policies that say how the South African coasts and oceans should be looked after and used.

This is why the Integrated Coastal Management Act (ICM Act) of 2008 was brought in.

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