“The additional fresh water made the ocean surface less dense and it stopped sinking, effectively shutting down the thermohaline circulation,” Schlesinger said. “As a result, Greenland cooled by about 7 degrees Celsius within several decades.

The currents flowing through the ocean, a process called thermohaline circulation, can have an impact on climate. Cold winds blowing over the oceans chill the waters beneath them. These winds also increase evaporation rates, further removing heat from the water.

The ocean’s thermohaline circulation has long been recognized as potentially unstable and has consequently been invoked as a potential cause of abrupt climate change on all timescales of decades and longer.

Ocean currents act as conveyer belts of warm and cold water, sending heat toward the polar regions and helping tropical areas cool off, thus influencing both weather and climate. The ocean doesn’t just store solar radiation; it also helps to distribute heat around the globe.

Global warming could potentially cause a thermohaline circulation shutdown and subsequent regional cooling, but because Earth will continue to warm as a result of greenhouse gas emissions, it would not produce another Ice Age.

Lecture notes from one of Columbia University’s 2007 “The Climate System” class suggests this process takes between 100-1000 years. This paper says Thermohaline Circulation overturns deep water every 600 years or so.

Currents Tutorial Thermohaline circulation begins in the Earth’s polar regions. When ocean water in these areas gets very cold, sea ice forms. The surrounding seawater gets saltier, increases in density and sinks. This process is known as thermohaline circulation.

This heat is transported by ocean currents. In this way, the ocean currents help regulate Earth’s climate by facilitating the transfer of heat from warm tropical areas to colder areas near the poles. The global wind patterns cause the surface currents to form in the uppers layer of the ocean.

These deep-ocean currents are driven by differences in the water’s density, which is controlled by temperature (thermo) and salinity (haline). This process is known as thermohaline circulation. In the Earth’s polar regions ocean water gets very cold, forming sea ice.

It takes about 500 years for the conveyor belt to turn over the ocean’s waters and make one complete trip around Earth.

Thermohaline circulation begins in the Earth’s polar regions. When ocean water in these areas gets very cold, sea ice forms. Surface water is pulled in to replace the sinking water, which in turn eventually becomes cold and salty enough to sink. This initiates the deep-ocean currents driving the global conveyer belt.

The currents flowing through the ocean, a process called thermohaline circulation, can have an impact on climate. What is thermohaline circulation? Cold water, in general, is denser than warm water.

At this point the two branches of the thermohaline circulation finally begin to mix with the lighter, warmer waters above and work their way back to the surface. Scientists estimate that the trip from the North Atlantic to the deep water upwelling sites in the Pacific takes about 1,600 years.

The thermohaline circulation, often referred to as the ocean’s “conveyor belt”, links major surface and deep water currents in the Atlantic, Indian, Pacific, and Southern Oceans. Multiple mechanisms conspire to increase the density of surface waters at high latitudes. Cold winds blowing over the oceans chill the waters beneath them.

The ocean’s global circulation system plays a key role in distributing heat energy, regulating weather and climate, and cycling vital nutrients and gases. Density differences in ocean water drive the global conveyor belt. This global circulation system is also called thermohaline circulation.