What is thermohaline circulation and what causes it?
This very large, slow current is called the thermohaline circulation because it is caused by temperature and salinity (haline) variations. As a result, both the surface and deep waters flow from west to east around Antarctica. Is the ocean conveyor belt thermohaline circulation?
What is meant by thermohaline circulation?
Thermohaline Circulation Density differences in the ocean can drive currents, with dense water sinking and moving from the Poles towards the equator. Density and wind-driven currents that transport heat (thermo) and salt (halo) are collectively referred to as the thermohaline circulation, which is also called the meridional overturning circulation.
What causes Thermohaline currents?
surface currents are caused by wind while thermohaline currents are caused by density differences caused by salinity and temperatures. Compare and contrast western boundary currents to eastern boundary currents.
Is the thermohaline circulation changing?
Is the thermohaline circulation changing? The Thermohaline Circulation influences the climate all over the world. A shutdown or slowdown of the thermohaline circulation is a hypothesized effect of global warming on a major ocean circulation. A 2015 study suggested that the Atlantic meridional overturning circulation (AMOC) has weakened by 15-20 ...
What would happen without thermohaline circulation?
- If global warming shuts down the thermohaline circulation in the North Atlantic Ocean, the result could be catastrophic climate change. The environmental effects, models indicate, depend upon whether the shutdown is reversible or irreversible.
What would happen if the ocean circulation stopped?
If it continues to slow, that could have profound consequences for Earth's inhabitants. Studies suggest it would mean much colder winters and hotter summers in Europe, changing rainfall patterns in the tropics, and warmer water building up along the U.S. coast that can fuel sea level rise and destructive storms.
Why do we need thermohaline circulation?
Thermohaline circulation plays an important role in supplying heat to the polar regions. Therefore, it influences the rate of sea ice formation near the poles, which in turn affects other aspects of the climate system (such as the albedo, and thus solar heating, at high latitudes).
What will likely happen to temperatures in Europe if thermohaline circulation stops?
If the currents were to stop completely, the average temperature of Europe would cool 5 to 10 degrees Celsius. There would also be impacts on fisheries and hurricanes in the region. The currents in the North Atlantic are part of a global pattern called thermohaline circulation, or the global ocean conveyor.
Will the thermohaline circulation stop?
At the moment, despite the warming, ice is not melting in Antarctica, but only near the Arctic. This pattern will tend to slow down or even shut down thermohaline circulation. If ice were to melt in Antarctica as well, then thermohaline circulation may not be affected in the same way.
How would shutting down thermohaline circulation affect Western Europe?
Shutting down the thermohaline circulation would reduce the amount of warm surface water flowing from the Gulf of Mexico to Europe and this would cause western Europe Page 3 experience colder temperatures.
What can affect thermohaline circulation?
Since freshwater is less dense than saline water, a significant intrusion of freshwater would lower the density of the surface waters and thus inhibit the sinking motion that drives large-scale thermohaline circulation.
How will climate change affect thermohaline ocean currents?
Warming temperatures result in weakened currents. If the water at the poles is not as cold and dense, it simply won't be able to circulate as well. Additionally, the melting of the Greenland continental ice sheet is pouring freshwater into the salty ocean, again altering the density of the water masses.
Could the day after tomorrow really happen?
While most of The Day After Tomorrow is safely in the realm of science fiction, there is some real science to back up concerns about potentially irreversible changes in our climate within a couple of decades that would affect our communities, health, infrastructure, and ecosystems.
When was the Earth warmer than it is now?
Even after those first scorching millennia, however, the planet has often been much warmer than it is now. One of the warmest times was during the geologic period known as the Neoproterozoic, between 600 and 800 million years ago. Conditions were also frequently sweltering between 500 million and 250 million years ago.
Can we live without the ocean?
Without healthy oceans, our life on Earth would be severely challenged, unpleasant and perhaps impossible. The oceans are the life support system of all living beings. That's because life on Earth can thrive without land, but it cannot exist without an ocean.
How does ocean circulation affect climate?
Ocean currents act much like a conveyer belt, transporting warm water and precipitation from the equator toward the poles and cold water from the poles back to the tropics. Thus, currents regulate global climate, helping to counteract the uneven distribution of solar radiation reaching Earth's surface.
What would happen if the thermohaline circulation shut down?
If global warming shuts down the thermohaline circulation in the North Atlantic Ocean, the result could be catastrophic climate change. The environmental effects, models indicate, depend upon whether the shutdown is reversible or irreversible.
Where does the circulation pattern move?
Like a great conveyor belt, the circulation pattern moves warm surface water from the southern hemisphere toward the North Pole. Between Greenland and Norway, the water cools, sinks into the deep ocean, and begins flowing back to the south.
Is thermohaline shutdown reversible?
The environmental effects, models indicate, depend upon whether the shutdown is reversible or irreversible. “If the thermohaline shutdown is irreversible, we would have to work much harder to get it to restart,” said Michael Schlesinger, a professor of atmospheric sciences at the University of Illinois at Urbana-Champaign and a co-author ...
Does Greenland have a thermohaline circulation?
Paleoclimate records constructed from Greenland ice cores have revealed that the thermohaline circulation has, indeed, shut down in the past and caused regional climate change.
What is the THC circulation?
Thermohaline circulation ( THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. The adjective thermohaline derives from thermo- referring to temperature and -haline referring to salt content, factors which together determine the density of sea water. Wind -driven surface currents (such as the Gulf Stream) travel polewards from the equatorial Atlantic Ocean, cooling en route, and eventually sinking at high latitudes (forming North Atlantic Deep Water ). This dense water then flows into the ocean basins. While the bulk of it upwells in the Southern Ocean, the oldest waters (with a transit time of around 1000 years) upwell in the North Pacific. Extensive mixing therefore takes place between the ocean basins, reducing differences between them and making the Earth’s oceans a global system. On their journey, the water masses transport both energy (in the form of heat) and matter (solids, dissolved substances and gases) around the globe. As such, the state of the circulation has a large impact on the climate of the Earth.
How does water affect the climate of the Earth?
As such, the state of the circulation has a large impact on the climate of the Earth.
What happens when the ocean water gets cold?
When ocean water in these areas gets very cold, sea ice forms. The surrounding seawater gets saltier, increases in density and sinks. Winds drive ocean currents in the upper 100 meters of the ocean’s surface. However, ocean currents also flow thousands of meters below the surface.
Why does sea water get colder?
In the Earth's polar regions ocean water gets very cold, forming sea ice. As a consequence the surrounding seawater gets saltier, because when sea ice forms, the salt is left behind. As the seawater gets saltier, its density increases, and it starts to sink. Surface water is pulled in to replace the sinking water, ...
How does thermohaline circulation affect the ocean?
Thermohaline circulation is highly depended on water density whereby the denser cold water will sink deep into the ocean and start the circulation cycle. When the earth is warm due to global warming, ice sheets at the pole will melt. The melting of ice sheets adds volume to the freshwater making the salinity level lesser than usual preventing the cold waters from sinking. This disrupts the ocean current pattern.
What is the Atlantic Meridional Overturning Circulation?
The Atlantic Meridional Overturning Circulation (AMOC) is the ocean current pattern helping to regulate the weather system carries warm water from the Southern Hemisphere and the North and to the North Atlantic. AMOC is a part of the thermohaline circulation that comprises of the warm gulf stream. In simple term, since the salinity and temperature of the water vary (slightly) from places affect the density of the water, this ocean stratification allows water to be transported from one region to the other.
What would happen if the currents in the North Atlantic were stopped?
If they were to stop, this would not be the first time that the global ocean conveyor was halted.
What would happen if the ocean currents stopped?
If the currents were to stop completely, the average temperature of Europe would cool 5 to 10 degrees Celsius. There would also be impacts on fisheries and hurricanes in the region.
How does melting ice affect ocean currents?
How Melting Arctic Ice Affects Ocean Currents. Worldwide, seawater moves in a pattern of currents known as thermohaline circulation, or the global ocean conveyor. The currents flow because of differences in water density and move between the deep and surface ocean. In the North Atlantic, water heated near the equator travels north at the surface ...
Why does cold water sink to the ocean?
As it cools, it becomes more dense and, because cold water is more dense than warm water, it sinks to the deep ocean where it travels south again. More warm surface water flows in to take its place, cools, sinks, and the pattern continues. However, melting Arctic sea ice and melting Greenland glaciers could change this pattern of ocean currents, ...
Why is the Arctic sea ice melting?
Recent research shows that Arctic sea ice is melting due to climate warming. The melting ice causes freshwater to be added to the seawater in the Arctic Ocean which flows into the North Atlantic. The added freshwater makes the seawater less dense. This has caused the North Atlantic to become fresher over the past several decades and has caused ...