Oceans, being an important part of global ecosystem, both affect and are affected by the climate change. Their role in this change is conditioned by their role in storing huge amounts of heat, moisture and carbon dioxide, which leads them to influence climate and modulate natural and anthropogenic climate change. Climate change has to be considered by humanity with respect to activities connected with exploitation of ocean riches. At this point, it is impossible to predict exactly how climate will change on earth in the next few years, but it is clear that it is dependent on complex interactions between land, air and oceans.
Oceans “are crucial in shaping climate because they store and move heat around the planet, and they’re a major source and storehouse for gases (such as carbon dioxide) that affect climate”, although scientists have not yet discovered the exact amount of gas oceans are capable of absorbing (NASA). The climate change that will affect oceans will most probably be manifested in the proliferation of hurricanes and increase in their strength. Hurricanes are expected in the first place in coastal North America and the Far East.
Next, if temperatures in parts of the oceans that are regularly covered by ice fall below freezing temperature, this may adversely impact the neighboring land. Thus, a rise in the level of the oceans will leave the shores submerged under water. This will affect both coastal areas and islands, being detrimental to the island biodiversity. In small islands in particular, fauna that lives there will see their natural habitat shrinking, which may lead to a drop in populations. Islands that lie at a low level may go under water entirely.
Warming of the ocean can also be detrimental to the coral reefs that derive some of their energy from algae residing inside their tissue. On the contrary, a rise in temperature can drive out algae, leading to the “bleaching” of coral reefs. At the same time, warming can be expected to benefit coral reefs as “it could also expand areas of warm water that corals need to grow” (NASA). These are relatively small-scale effects that are supposed to come from the disruptions in the oceanic climatic conditions. More serious effects will result from the disruptions of the oceanic currents that play a major role in defining the earth’s climate.
At this point, the oceans include a special mechanism called the Conveyor that embraces large oceanic currents moving around the earth that “distribute vast quantities of heat around our planet, and thus play a fundamental role in governing Earth’s climate” (Gagosian 2003). This mechanism, for instance, includes the Gulf Stream that carries warm water from the equator to Northern Europe and North America, making the waters around this area warm up. In case the Conveyor suffers disruptions, the northern regions may not receive the usual amount of heat, which will lead to substantial climatic changes.
A similar demonstration of oceanic role in climate change is the El Nino phenomenon that affected the Humboldt Current. El Nino has led to drought in the Western Pacific, floods in East Africa and similar disruptions (Rahmstorf 1997). In the North Atlantic in particular, an influx of fresh water could dilute the salty and dense waters brought from the tropical areas, thus hampering normal exchange of temperatures. As a result, the region can cool even when the whole Earth is warming up. Cooling would lead to persistently cold winters that could stay in the area for decades or even centuries, thus affecting biodiversity.
Small ecosystems like small islands would be especially threatened since they represent fragile systems where variety of species can be put at risk with a minor change. Thus, oceans have an important role in climate change. Warming up, oceans will submerge coastal areas and island shores, ‘bleach’ coral reefs, and generate hurricanes on a larger scale. Most importantly, disruptions in the Conveyor mechanism including oceanic currents will cause long-lasting changes in climate, affecting biodiversity.