Fresh Water Is Being Added To The Oceans At The Polar Regions Due To The

Fresh water is being added to the oceans at the Polar Regions due to the melting of ice, while the fresh water is being lost from the tropical regions due to evaporation and other losses. The modelling of the action of the oceans is complex and there are uncertainties in the models. However, scientists have discovered a certain hysteresis like action in the response of the oceans to the forcing action of the additional energy being absorbed from the Sun.
Scientific examination of sediments from deep oceans and ice cores indicates that it is very likely that the Great Ocean Conveyor Belt did indeed malfunction at some point about twelve thousand years back.This stoppage of the ocean mixing mechanism resulted in what is known as the Little Ice Age, when for about a thousand years the North Atlantic became very cold and as a result of the climate change, the Vikings were forced to migrate from the Polar Regions to those parts of Europe which are closer to the tropics. In the present age too, it is very likely that a stoppage of the Great Conveyor Belt coupled with an increased global warming as a result of the greenhouse gas effect will result in an overall warmer Earth, which is warmest at the tropics but coldest at the Polar Regions. It must, however, be realised that the modelling of ocean action and the Earth's response to greenhouse gasses is complex and the oceans are also subject to random fluctuations which are not very well understood.
Conclusion
From the previous discussion and in the light of the discussions presented in current scientific literature, it may be concluded that there is a general global warming as a result of the gaseous emissions from the burning of fossil fuels. These greenhouse emissions act in a manner that is similar to that of a greenhouse in trapping solar energy within the Earth's atmosphere. However, there is evidence that this general global warming is further interfering with the mechanisms such as the Great Ocean Conveyor Belt action, which nature has established to maintain the global climate. Thus, although the Earth's oceans are able to absorb the effects of humanity's luxuries, there are limits to such capabilities and it is desirable that serious efforts should be made to limit fossil fuel emissions which bring about serious threats to the global climate system by attempting to develop alternative energy sources and limiting fossil fuel emissions.
References / Bibliography

---. Climate Change: Assessing the Impacts - Identifying Responses: Highlights of the First Three Years of the UK Climate Impacts Programme. [London]: Department of the Environment, Transport and the Regions, 2000.
---. Climate Change: Critical Concepts in the Environment.