THE NORTH AND SOUTH POLE
A video of the polar climate. https://www.youtube.com/watch?v=ruMQRCRMAnI
Every winter, the oceans around the poles freeze to form the sea ice. Due to the salinity of the sea water, the surface begins to freeze from 28,76°F (-1, 8°C). The sea ice of the poles is an important element in the climate due to the albedo.
When talking about the surface of the sea ice, so do not confuse
the extent (09/21/07: 4,14 millions Km²) and the area
(09/21/07 : 2,92 millions Km²).
Because of global warming the surface of the Arctic sea ice is decreasing year to year and see more and faster in recent years. In September 2007 the melting of sea ice reached a record with an area of only 4,14 millions km², so 1,2 million km² (about twice the surface of France) less than the previous record set in September 2005 with an area of 5,32 millions km². This shows that within two years, the surface of sea ice has lost 22%. The rate of melting of ice since 1979 is 10% per decade. The rate of melting of ice since 1979 is 10% per decade. The decrease in the surface of the pack ice that was concentrated in the eastern Arctic therefore off the coast the Eurasian continent, as this is where the ice is the younger and thus slimmest and the most sensitive.
Ice from the sea ice shrinks not only on the surface but also in thickness. Reducing the coverage of sea ice in the Arctic Ocean is about 40%, and is thus changed from about 3,1 m to 1,9 m between 1950 and 1997. In 6 years (from 2001 to 2007) the thickness of the pack ice is even decreased from 1,9 m to 1 m.
The Arctic sea ice also evolves according to the climatic phenomenon the Arcti Oscillation (AO) which has links with the strength of the polar vortex.
Created and updated with the data NOAA
Une vidéo de l'Antarctique https://www.youtube.com/watch?v=Ymxi5wsqtEU
Unlike the Arctic, the maximum surface of the Antarctic pack ice is increasing since 1997. In 2012 it reached a record high of 19,39 millions km2, in 2013 it reached the new record of 19,77 millions km2 and in 2014 it exceeded 20 million km2. See here the records of its surface since 1979 including the first 8 records that occurred in the last 15 years.
Because of the cold greater than in the North Pole, the surface and the thickness of the Antarctic pack ice is greater than that of the Arctic which gives a stronger polar vortex over Antarctica.
The evolution of the Antarctic ice evolves according to the climatic phenomenon the Antarctic Oscillation (AAO) which has links with the power of the polar vortex and direction of winds.
Created and updated according to NOAA data
BETWEEN THE SEA ICE OF THE NORTH POLE AND SOUTH POLE
After analyzing methane drilling ice cores in Greenland Grip in 1992 and that of Antarctica that showed a good time resolution in the evolution of temperatures of the poles. The concentration of methane shows large and rapid changes at the poles made during the passage of warming or cooling during the last glacial period (from -100,000 to -12,000 years before the present). It's 24 "Dansgaard-Oeschger" (D / O) events that occurred during the last glacial period. These events are sudden warming of 46,4-60,8°F (8-16°C) which are developed in less than 300 years. Which is fast compared to an input or an output of an ice age which is about 10,000 years. These oscillations have occurred approximately about every 1470 years during the Dansgaard-Oeschger events, but during the Holocene, the result has waited more than 3000 years to manifest. Some scientists estimate that this could occur when the minimum or the maximum of solar activity of Suess and Gleissberg cycles occur simultaneously. But evidence has not yet been found.
Following the analysis of Thomas Blunier and colleagues temperature changes in the Arctic and Antarctica have evolved the opposite.When Greenland starts to warm up during Dansgaard-Oeschger events, Antarctica has a reverse behavior and cools.
The cause of this opposite evolution between the two poles could be due to ocean currents because during the Dansgaard-Oeschger events sedimentary data show that ocean circulation is disrupted. Because the melting of the ice of the north pole during the warming would slow the thermohaline circulation because rejected fresh water would disrupt the thermohaline diving in North Atlantic which would destabilize the Gulf Stream, the main current of the North Atlantic. So when the Gulf Stream brings no more heat to the North, the North Pole cools and the heat that is stored in the Southern Ocean warms the south pole with a lag. Changes in Antarctica are more progressive and less important than that of the North Pole. Then when it ocean current restarts, it warms again Greenland and reverse for the Antarctic.
In 1988, analyzing the marine sediments of the North Atlantic, the German geologist Hartmut Heinrich found detritus scraped by glaciers. These events would have occurred six times during the last glacial period. All of them are written H0, H1 to H7 for the latter.
Evolution of temperature in Antarctica and Greenland
As shown in this diagram, the minimum extension
of the pack ice during the