The oceans and the atmosphere are tightly linked, and together form the most dynamic component of the earth’s climate system. Oceans store heat. When the earth’s surface cools or is heated up by the sun, the temperature change is greater and faster over land than over the oceans.
Winds and currents are constantly moving the ocean’s waters. The Gulf Stream Drift, for example, is powered by cold, dense, salt-laden water sinking off the north polar coastal regions and moving south in the depths, pushing the surface warm water from the tropical and subtropical Atlantic (including some from the Gulf of Mexico) up north to bathe the shores of Western Europe, producing a climate that is surprisingly mild for that latitude.
Global warming and melting of the polar ice-caps freshens the surface water, reducing its density and preventing it from sinking. As a result, the Gulf Stream slows down, or may even reverse, bringing severe winters to northern Europe while the rest of the earth heats up.
All over the world ocean waters are warming as a result of global warming putting stress on marine ecosystems and sea life, already under siege from pollution, overfishing and habitat destruction. Warmer oceans also mean that ice caps are going to be melting faster, the rising sea-level will put underlying coastal areas at risk of being submerged. Sea levels are predicted to rise 7 to 23 inches by the end of the century, plus 4 to 8 inches if recent melting in Greenland and Antarctica continues. Many scientists consider these conservative estimates.
Apart from this there is going to be a direct influence on global weather patterns with increase in hurricanes and typhoons. We have already seen evidence of this. Additionally, winters in northern Europe and Scandinavia have grown wetter, while those in southern Europe and the Middle East have become dryer. European farmers have encountered an earlier and longer growing season. The habitats and life cycles of many marine and terrestrial species have changed. There have been changes to the monsoon in India and the Pacific Southwest as well.
Food for thought: The planet's weather not only supports its varied species of life, it also supports global economy. The biggest economic sectors directly affected by climate change are agriculture and the fishing industry. The warming up of our oceans is a bigger threat to human survival than anything else we currently face. A continued increase in ocean temperatures will see the top predator species of the food chain extinct with oceans reverting back to the primordial soup stage of early creation.