Global Warming & Ocean Currents

Christian Dunn May 9, 2006 The Effect of Global Warming on Ocean Currents Component of the Greenland Ice Lab Although its exact cause is unknown and debatable, the warming of the earth that is occurring today which is often referred to as Global Warming is likely to result in significant change in the biosphere of the Earth. One change that is of worry to climatologists and is imminent if warming trends continue is a disruption of ocean currents. Ocean currents would be disrupted significantly in a century and completely halted in an estimated two centuries at the current rate of warming1. Ocean currents play a significant role in providing warmth to Europe and over a year’s average, provides one third as much warmth to Europe as the Sun does2, and if these currents were disrupted, the average temperature in Europe would decrease massively, virtually freezing the continent. Freshwater from melted ice from the Arctic Ocean and ice caps in the area because of warming temperatures would directly impact and eventually cool temperatures in areas which gain heat from the ocean currents, mainly Europe. When ocean currents function as they currently are, warm water from the south flows northward. The warm, northerly flowing water stays on top of the deeper waters in the ocean because of its warmth and lower salt content which makes it less dense. When the reaches cooler, northerly parts of the ocean, it gives up most of its heat to Europe and becomes very cool and dense. In addition, this cool water becomes very salty because some water evaporates on its movement north. This dense water sinks very deep and then flows south, where it then rises again and is warmed and continues on its cycle northward again. The reason global warming would disrupt this cycle is because the warming temperatures would melt glaciers and ice caps which would release a great amount of fresh water into the ocean. An influx of fresh water in the ocean would mean that the water which sinks in cool areas because of its saltiness would be less salty, and if 1

Ruth Curry and Cecilie Mauritzen. Norwegian Meteorological Institute. Oslo. Dr. John Gribbin. Ocean Forces Threaten Our Climate. Online Available at www.firstscience.com/site/articles/gribbin.asp. Article Published 2005. Viewed 5/9/2006. 2

Christian Dunn May 9, 2006 that water lost so much of its saltiness to being mixed with fresh water that it did not sink enough or at all, the ocean current would be disrupted or halted. While it is unknown whether the conditions in the future will change enough to disrupt ocean currents, it is a possibility. Stefan Rahmstorf, a professor of ocean physics at Potsdam University in Germany believes the chance of an ocean current shutdown is 30%3. Any possibility of an ocean current shutdown poses a danger of the continent of Europe being cooled significantly as a result of a global warming trend.

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John Roach. Global Warming May Alter Atlantic Currents. National Geographic News. Article Published 6/27/2005. Viewed 5/9/2006.