On this page we will present you a couple of facts about climatic change and how this affects not only the oceans, but also life on land. It is interesting to see, that water, land and air (atmosphere) are influencing each other heavily. Therefore, a change of climate in our atmosphere due to the gases produced by industry, traffic but also anthropologically, will directly affect the oceans as well, even though we immediately associate this kind of pollution with "air" and "climate". Find out below how this issues are interrelated and how we could be affected by them.

Ocean Temperatures / Water Circulation / Coastal Areas / People / Coral bleaching

Ocean Temperatures:

The general warming of temperatures due to climatic change will increase the average water temperature in our oceans. And when the temperature of saltwater rises, the capacity of the water to absorb and store carbon dioxide decreases. It is estimated that about one quarter of all anthropologic carbon dioxide emissions are being absorbed (through photosynthesis) by the terrestrial flora and fauna. But another quarter are being absorbed by the oceans either through chemical or biological processes. Consequently, an increase in water temperatures would lessen the absorption of carbon dioxide, the main greenhouse gas. However, it is difficult to estimate the percentage of "rejected" carbon dioxide. But even now, the oceans are a huge storage room for carbon dioxide. The oceans contain fifty times the amount of carbon dioxide than does the atmosphere and twenty times more than the biosphere. Vice versa, it is a unique feature of the oceans, that they are capable to contain a large amount of cold and deep water oversaturated with carbon dioxide from escaping to the atmosphere by means of a thin layer of warmer surface water.

Water Circulation:

Another factor which affects the oceans capacity to absorb carbon dioxide is dependent on water circulation. It is assumed, that a change in climate would also affect the present patterns of water circulation around the world, because the climate directly affects water circulation and currents. Some scientists suggest that when the surface temperature increases, the thermocline (the layer of water between the warmer surface water and the colder, deeper waters, e.g., you can feel this when you go swimming or diving) will become more stable and thus resistant against the vertical mixing of the two separated layers. A more resistant borderline, however, would decrease the supply of carbon dioxide from the atmosphere to the colder waters where phythoplankton absorbs the gas, once again slowing the absorption of anthropologic gases.

Coastal Areas:

Climatic change and consequently warmer water temperatures will influence the sea level and thereby affect coastal areas in their very existence. Scientific models suggest that if there are no serious attempts to reduce greenhouse gases, the sea level will have risen about 20 centimetres by the year 2030, and by the end of the century about 65 centimetres. The reason for this is the heat-related expansion of H2O and the melting of the polar caps. But the real danger lies in the potential breaking off of the huge glaciers in western Antarctica. Should this area crumble due to increasing temperatures, sea levels would rise approx. by about five meters. A case study like this is, of course, somewhat speculative. But even a much slighter rise in sea levels would lead to horrendous problems. Coastal areas would be flooded, countries like Egypt and Bangladesh would lose much of their fertile territory to the oceans, island states like Tuvalu, the Maldives and Kiribati would partially disappear under water, coastal acquifiers would be rendered useless and dikes (for expl. in the Netherlands) would be severely damaged or destroyed. Together with yearly floods, rainperiods and monsoons, a rise in sea levels would prove a deadly package.

People:

By the time melting polar caps would lead to a dangerous rise in sea levels, the world's population is likely to have doubled or more. Naturally, such a development would only exacerbate the problems. Millions, if not billions would be affected in such a way, that their traditional way of life, if not their lives themselves would be threatened. The political, economic, social and sanitary consequences would be grizzly. A rise in temperatures in general would also allow bacteria and viruses to spread northwards, many of whom breed in water.

Coral bleaching:

Coral bleaching appears to be a major threat to coral banks around the world in 1997/98. Vast areas in prime diving spots such as the Maldives, the Seychelles, the Great Barrier Reef or the Cocos Islands belonging to Costa Rica have suffered from this phenomenon. Coral bleaching happens, when the symbiosis between coral polyps and their host algea is ruptured. The polyps then reject the algea giving the corals their distinctive bright colours. Having expelled the subletting party, the chalk skeletton of the corals starts simmering through the color of the algea. The consequences are a decrease in photosynthesis and thus a reduction of carbon dioxide and organic matter. In addition, the algea further the production of chalk by absorbing carbon dioxide from the water. The main factor causing coral bleaching is the increasing water temperature in the wake of El Nino. There is a high correlation of coral bleaching and water temperatures above 30 degrees celsius. Warm water increases the productivity of the algea, leading to increasing oxygen, which, in a high concentration, becomes poisonous and a danger to the polyps. Without the algea, however, no structured coral reefs can grow. But almost all coral reefs in the world have been hurt and not all recovered, once the warmer water receeded.

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Update: May 1, 2000