Topic POL within MARCOPOLI

During most of the year, the earth’s surface in polar regions receives little or no solar radiation. Consequently, temperatures are low year-round. For many millions of years, extensive ice caps have been forming both on land and on the ocean. Nowadays, even a slight warming of the polar regions and melting of ice shields can cause global changes to climate and the environment, such as a worldwide rise in sea levels. Hence, the polar regions are of extraordinary significance for nature and humans.

Land, ocean and atmosphere in the polar regions are strongly interconnected through numerous special physical and chemical processes. Under the cold conditions of the past millions of years, the polar system was stable. Rising temperatures, caused, for instance, by higher concentrations of greenhouse gases in the atmosphere, lead to system instability. Changes such as melting glaciers and warming polar oceans affect the global climate balance. The Antarctic Circumpolar Current is linked to northern ocean systems through oceanic currents. The cold, high-density waters of the polar seas drive the global atmospheric and oceanic circulation. With rising temperatures in the polar seas, those currents, powering global climate, will diminish, and the far-reaching environmental effects will be felt globally, including at temperate latitudes.

The characteristics of sea ice, seasonally variable, affect both atmosphere and oceans worldwide. Sea ice provides habitat for many marine organisms, and despite the extremely harsh environmental conditions, biomass production associated with sea ice is very high. Especially diatoms, optimally adapted to the cold conditions, inhabit a system of brine channels in the sea ice. The inland ice shields of the polar regions are integral components of the climate system. On the one hand, they respond quickly to changes in climate; conversely, alterations of the ice shields have effects on the climate globally. At the same time, the inland ice shields preserve the climate history of the past. Ice cores represent unique archives in that the formation and preservation of ice, thousands of years old, is clearly connected to processes in the atmosphere from that time. Marine ecosystems and organisms of the polar regions have evolved the best possible adaptations to permanently cold conditions. They survive severe food shortages and large seasonal temperature fluctuations.

Regional processes in the polar regions can trigger large-scale dynamic mechanisms, which is why the polar regions are under particular observation. Hence, understanding the processes operating in those regions, and evaluating their significance within the system Earth, is essential.