Changes in Ocean Currents

In a recent study on the the Gulf Stream, NASA scientists determined that, contrary to recent rumors, the Gulf Stream is not in immediate danger of shutting down. Their research found no trends in current flow other than an insignificant increase in flow since 1993, which scientists deemed part of the natural heating and cooling cycle of the Atlantic (Telegraph).

In an article published last month, a team of scientists discovered that Apherusa glacialis, a type of crustacean that lives in the cold areas off the coast of Greenland, actually uses ocean currents to migrate to colder areas when warmer summer temperatures cause some of the ice to melt. The scientists called this the "Nemo hypothesis" because of the Disney movie Finding Nemo, in which Nemo's father uses the East Australian Current to travel through the ocean to find his son more quickly. This adaptation gives hope that organisms who thrive in icy environments have a stronger chance of survival despite the imminent increase of temperatures due to global warming. However, one problem that still remains unsolved is what will happen if there is no more ice available elsewhere to which these organisms can migrate.

A recent study was performed on the circulation in the North Atlantic Ocean to discover more information about climate change and change in ocean currents. The data suggest that it could be possible that in past major climate shifts, ocean currents have actually changed before the climate did. Scientists concluded that the ocean current shut down about 600 years prior to the Younger Dryas, a cold snap that occurred about 12 million years ago. This evidence suggests that there may be another factor in regulation of ocean currents and that the change in currents has a subsequent effect on climate. Link to Article

In a study published this past September, scientists have linked the wind patterns in the stratosphere directly to deep ocean currents. The polar vortex is the term used for the winds high above the Arctic. Changes in these winds can easily effect a change in the weak spot of the Gulf Stream, which is located just south of Greenland, causing ocean water to sink, and the ocean currents will change as a result. About every two years, the polar vortex, which usually move counterclockwise, will slow and may even begin to rotate clockwise instead. This shift has a direct effect on the Gulf Stream by causing it to slow down or speed up. Thus, anthropogenic effects on the stratosphere will affect ocean currents indirectly through climate change but also through the effect of the polar vortex on ocean currents directly.


(From Huffington Post)

Ocean currents can also have an effect on Oxygen Levels, as discussed in a recent article reviewing Peter D. Ward's book called "Under a Green Sky: Global warming, the mass extinctions of the past, and what they can tell us about our future" (Read article here). Too much ice melting due to global warming releases cold water into the oceans and disrupts the ocean currents that move the water from deep to shallow and help keep oxygen in the oceans. This disruption lowers oxygen levels and may result in a "Canfield ocean," an environment in which oxygen-using organisms cannot survive.

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