Polar territories are due to their climatic conditions, as is known, Ice territories. As such ice is fluctuating; His swings in geological time, and historical included, They are the keys to its status and its dynamics.
Already at the end of the 19th century, maps were published with the extension of the "old and current" terrestrial ice- according to them-, Marine and continental ice. Then, The planet Earth had just left, about twenty or thirty years before, According to latitudes, of a small glaciation. It had not yet been erased, therefore, The direct memory of its historical advances both in the remote lands of high latitudes and in high mountain ranges. Even the Pyrenees, the European Picos and Sierra Nevada experimental, although limited to its situation and altitudes, Such historical era glaciers advances. The geographical knowledge of such areas, although still inaccurate in the last quarter of the nineteenth century with respect to polar regions and high mountains, It already allowed an approach to the cartography of the nuclei and contours of those ice masses. Addition, The theory of great quaternary glaciation, Born and developed some decades before by Alpine naturalists, I asked scholars for their verification or adjustment with specific data.
Already at the end of the 19th century maps were published with the extension of the "old and current" terrestrial ice, Marine and continental ice
The great glaciation of the late Pleistocene and its great swallowing have no comparison with anything that has happened in the terrestrial glacier field in the last 10.000 years or more. Polar areas, although their setbacks attenuated for their extreme climates -as it shows the persistence of its icy regions, marinas and land- They also experienced very notable volume and glacier extension losses. But it was in the remaining terrestrial continental areas where only residual ice cream were left, with variable dimensions because of its different latitudes, geographical positions and altitudes.
In polar areas, glacial phenomena and processes have zonal scale and, in consecuense, The dimensions of the ice have tended, Despite his setbacks, At least permanence or at least a certain inertia. Instead, In its peripheries and in the restricted continental and insular glacier areas, Logically, limited glacier fluctuations have been observed after that great thaw. But these fluctuations of advances and setbacks, although reduced in time and space, They have been several and repeated until today in the millennia after the merger, mentioned above, of the great glaciers masses of the Pleistocene.
The recoil of the ice appears accelerated and has already reached the large deposits of the cold
The multisecular advance of the recent small ice age and its subsequent setback (in which we are) It is registered, therefore, In that fluctuating behavior as his last sample. This historical glacier expansion was widespread in all the icy areas of the Earth and its description is old in geography manuals. The data provided by the historian Le Roy Ladurie They indicate that even in the thirteenth century Europe would have a climate of warm temperatures, that worsened in the XIV, standing in the year 1303 The climate cooling of what has been called small ice age. However, Its development as a really positive glacier phase is placed at later dates, as, After a bi -concible episode in the first half of the 16th century, The cold returned to Europe from 1560 and, particularly, In the nineties of that century. This relapse was reflected in a maximum glacier advance of this small age in the Alps. The positive glacial state stabilized in the seventeenth century, It went through a brief warm return in the early 18th and then intensified later at the beginning of the 19th century, to finally end up abruptly towards 1860. As of this date the withdrawal of ice in the Alps And the Pyrenees is progressive, although with some minor oscillations interspersed.
Today we are, as, In an extension of this withdrawal of the ice, But with characters intensified since the end of the 20th century. The setback appears accelerated and has already arrived - which is what matters to us here- To the great deposits of the cold: namely, to high mountain ranges and polar areas, maybe before unwritten or may be that without known data. Relatively, In the moderate proportions of what has been called a "small" glacier age ", We are now at the time of its great thaw, And this affects virtually all the glaciers of the globe, except for possible regional or local exceptions. This situation is, insist, generalized on the planet from Alaska the Greenland the Aneto or al K2 or al Himalayas or to the Antarctic Islands. It also includes, as, To polar and circumpolar areas, In its clear way it is, But within the general glaciological and climatological evolution of the Earth, naturally. As, also, These areas are the strict landscapes of cold and ice, Such a condition concerns, Not to an ingredient among others of the territory, but to its same geographical key.
This situation is generalized on the planet, From Alaska or Greenland to Aneto, Al K2, to the Himalayas or the Antarctic Islands
Glaciers advance, they move, they progress and regress and this dynamic gives them natural changes. It is their condition to be changeable. This is the essence of polar landscapes. What seemed immutable is, however, In full move. So, The analysis of the waters from the snow and the ice of Antarctica has a special interest, Because it provides revealing data on the atmosphere, especially in great depth perforations, as in Vostok, where ice has offered serial data that backed up for a long time and expressly. If it is time that creates, accumulates, modify and melt the ice, it is also true that ice, well examined, makes time speak, to all that time of your training.
The setbacks of sub -eloting ice have not been detected solely in the current moments. In the boreal zone there was talk of an "Arctic Reheating", Like a cold instability, already at the end of the 19th century and the beginning of the 20th, deduced from temperature rise observations, ice setbacks, Soil defrosting, Decreasing of the River frost period, Increase in warm marine current, Prolongation of migratory bird stay, etc..
The setbacks of the sub -elity ice have not been detected only now. In the boreal zone there was talk of an "Arctic Reheating" already at the end of the 19th century
Now, With concerns derived from a greater awareness of climate change, This type of data has acquired more relief, both in its evolution along millennia and in its current monitoring. So, jump to newspapers, eg, Information arising from NASA images that show the transformation for decades of polar frostwater surfaces: In the Arctic it was observed in 2012 that the extension of the oceanic ice layer had reached its minimum since 1979. But, It was simultaneously verified that the total extension of sea ice around Antarctica had expanded from 1978 a 2010. There was then talk of two opposite geographies, a, north, "Cutting Ice" between continents, increasingly restricted ice in its large inner lake, And another of "Pericontinental Open Ice", almost like an adhered circle around the Antarctica that beats twice a year, with easy expansion in the winter station towards the southern oceans and that retracts and thinns in the summers.
Marine arctic ice shows today real real losses, reducing its surface and opening in greater number and extension of internal channels
In sum, Marine Arctic Ice shows today clearly striking and significant real losses, reducing its surface and opening in greater number and extension of internal channels. Thereby, Some navigators, Heirs of those who have pursued the sea routes of the steps of the Northwest -along with the North American northern coast- and from the northeast -for the coastal seas of Eurasia-, They have returned to the old interoceanic communication initiatives through projects of a complete polar polar ring road along almost impracticable routes so far.
