Summit County Citizens Voice

Global warming could result in reversal of deep water circulation

New research confirms that major ocean circulations are very sensitive to shifts in salinity. GRAPHIC COURTESY NASA.

By Summit Voice

SUMMIT COUNTY — By tracing the age of isotopes in seafloor sediments, researchers say they’ve been able to pinpoint times when ocean circulations were dramatically different than today, including a period about 20,000 years ago. when the flow of deep waters in the Atlantic was reversed.

The findings, published in the journal NATURE, may offer some clues as to what might happen in the oceans as global temperatures heat up in the coming decades. The reversal happened when the climate of the North Atlantic region was substantially colder and deep convection weakened. At that time the balance of seawater density between the North and South Atlantic was shifted in such a way that deep water convection was stronger in the South Polar Ocean.

Similar changes in seawater salt concentration are expected to occur in the North Atlantic in the course of climate warming over the next 100 years.

The Atlantic Ocean circulation (termed meridional overturning circulation, MOC) is an important component of the climate system. Warm currents, such as the Gulf Stream, transport energy from the tropics to the subpolar North Atlantic and influence regional weather and climate patterns. Once they arrive in the North the currents cool, their waters sink and with them they transfer carbon from the atmosphere to the abyss. These processes are important for climate but the way the Atlantic MOC responds to climate change is not well known yet.

The data from the new study will help climate researchers develop more accurate models of what might happen with ocean currents in the coming century.

Filed under: Environment, global warming, Summit County Colorado Tagged: | climate, Environment, global warming, Gulf Stream, ocean currents, Southern Ocean, Summit County Colorado, Summit County News, Thermohaline circulation