Possibility of weakening "global ocean circulation" circulating seawater on a global scale due to global warming

ByKarl-Ludwig Poggemann

In the sea, which account for 70% of the surface area of ​​the Earth, sea water on a scale of several hundred years to 1000 years is circulated across the polar regions and near the equatorOcean general circulationThere is a phenomenon called called. This ocean current is believed to affect the calming of the earth's climate by circulating the heat that the earth receives from the sun together, but this current owing to global warming in recent years We are getting weaker.

Arctic sea - ice decline weakens the Atlantic Meridional Overturning Circulation: Nature Climate Change: Nature Research
http://www.nature.com/nclimate/journal/v7/n8/full/nclimate3353.html

Global Ocean Circulation Appears To Be Collapsing Due To A Warming Planet
https://www.forbes.com/sites/trevornace/2017/08/03/global-ocean-circulation-appears-to-be-collapsing-due-to-a-warming-planet/#7322ca8cf6f4

This research was jointly conducted by research teams at Yale University and Southampton University. The ocean general circulation is remarkable mainly in the Atlantic Ocean, the Pacific Ocean and the Indian Ocean, but one of them is the large current flowing across the Atlantic Ocean and the Arctic Ocean "Atlantic Meridional Overturning Circulation (AMOC)" current The fact that global warming has a negative influence is becoming emphasized.

The seawater heated by receiving the sun's energy near the equator moves to the north pole at a speed of several cm per second, producing AMOC. AMOC, a "warm current" of warm seawater, brings a temperate climate to the European countries located in the latitudinal part, reaching the cold waters around Greenland. Cooled sea water becomes smaller in volume and at the same time it becomes heavier due to the sea water density becoming higher due to salt released when "sea ice" made of sea is formed, and then slowly begins to sink to the bottom of the ocean . This flow occurs in a chain-like manner, and global currents are produced. This flowThermal salt circulationIt is called ocean current caused by force in the windWind cycleTogether, it is the driving force of the ocean general circulation.


It is a phenomenon that has been clarified this time that the flow of AMOC is weakened by the decrease of sea ice, which is one of the motive forces that generate thermal salt circulation. This is also highlighted from the following heat map showing the changes of the surface and sea temperature. This shows how much the average temperature in various parts of the Earth has changed from 1900 to 2012, and the red color means that the average temperature is rising. You can see at a glance that the temperature is rising on a global scale, that is, global warming is occurring, but you can see that the temperature is as it is, or rather it is slightly lower in a wide area of ​​the North Atlantic Ocean . In other words, it seems to imply that the heat is not carried because the circulating force warmed by the equator is weakening.


In 2004, the movie that depicts climate change due to changes in AMOCDay after Tomorrow"Has been released. In this work, the shocking scene that Manhattan in New York gets waved by the wave became a topic because torrential and tsunami occurred due to weathering of the earth caused by weakening ocean current. The impact of actual climate change is not thought to occur at the level of several years like this movie, but what kind of influence the ocean current change will actually have on the earth, who has yet to answer the question It is a situation that we have no choice but to wait for the time to come.