published on 6 September 2009 in energy
Oil fields beneath the ice
As global warming is causing the ocean ice to disappear, the Arctic Sea bottom has become the object of the most highly detailed cartographic study ever. One of the newest findings is a chain of volcanoes along the Gakkel Ridge which could imply varying boundaries among the nations looking on to the Arctic Sea: Canada, Denmark, Greenland, Norway, Russia and the United States (Alaska). The continental platform extension of these countries will determine each one’s territorial rights for the exploitation of oil and gas fields.
At present the Arctic is the fastest warming area on Earth and our knowledge of what lies beneath is changing just as rapidly.
The Arctic, a water and ice world
As opposed to the Antarctic, which is a continent, the little land that rises above sea level is made up mostly by islands and archipelagos. Therefore there are no vast glaciers or ice caps, but only a huge extension of ice floating on the Arctic Sea. Whereas glaciers and ice caps vary very little in size throughout the seasons, marine ice undergoes substantial changes of areas ranging from 15 to 20 million square kilometers on the polar seas which can be seen very clearly in satellite pictures. Marine ice rarely lasts for over a year and ice sheaths that last longer than that can be found only in the Arctic Sea.
Marine ice forms in a different way from glacier ice. It forms directly from sea water freezing when air temperatures stay below -1.8° C for a number of days. Its seasonal formation is spectacular: it begins with pin shaped or very thin layers of ice which float on the surface giving the sea a “greasy” appearance also known as grease ice. The ice crystals gather together forming thicker ice sheaths that collide with one another because of the waves thus becoming rounded in shape with upturned edges that make them look like pancakes which is why they are called pancake ice. As the temperatures stay below freezing, the sheaths bind together to form one big ice surface or pack. Its thickness ranges from 1 to 5 or 7 m. and increases continuously thanks to sea water freezing on its underside or snow falling on the surface.
Water currents, winds and storms keep the ice pack moving causing it to fracture, overlap and collide thus forming a tortured landscape made of jutting crests and large fractures that make its exploration extremely difficult.
The Arctic Sea’s summer ice cap is down to almost half its size and we can see this very clearly in the many satellite images that we can find on the web. Also the Greenland ice cap is melting rapidly. Marine ice that expands and contracts with the seasons has covered the Arctic Sea for almost three million years and now it has become very vulnerable to climate changes. Climate models from 10 years ago foresaw that Arctic ices would melt completely by the summer of 2100, but this date has been subsequently moved up to 2050 and then 2030.
Ice decrease will bring about an increase in navigation which nowadays is limited to warm current areas that keep the coast ice free. Winds and currents push the ice towards the Canadian Archipelago where there is a shortcut passage between the Pacific and the Atlantic Oceans: the northwest passage. Faster ice fusion has allowed this passage to be navigable at the end of the summer season every year since 2006.
During the last glacial era, sea levels sunk by about 110 m. compared to present day levels and a lot of land which is now submerged once used to be above sea level. For instance, there used to be a natural land bridge that connected Alaska to Siberia! This happens because during glaciation vast amounts of water are drawn away from the oceans and seas to become trapped in the ice caps and continental ice shelves. Therefore, during each glacial era, sea levels have shrunk considerably throughout the planet.
It is estimated that as much as one fourth of the world’s known oil and gas resources are under the Arctic Sea, most of which should be on the continental shelves. These deposits formed by algae and plancton date back to 100 million years ago when the Earth was warmer and the Arctic had no ice. In an era between the Triassic and Tertiary ages some arctic lands were almost tropical not only because global temperatures were warmer but also because they were located at warmer latitudes that in subsequent geological times have moved further north.
At present the Arctic Sea has some substantial oil fields which according to experts could amount to as much as one fourth of the world’s untapped reserves. If the nations looking on to the Arctic Sea succeed in expanding their boundaries northwards, they will be able to exploit these deposits that started forming 100 million years ago. Some experts estimate that there may be approximately 90 billion barrels of crude oil and 47,000 billion cubic meters of natural gas. Others are less optimistic and believe that natural gas may be plentiful but oil could be a lot less and fields locations may fall already within each country’s territorial waters. Marine ice fusion makes Arctic waters navigable and sea beds accessible to mining explorations.
A matter of boundaries
The United Nations Convention on the Law of the Sea says that every state has the right to establish the breadth of its territorial sea up to a limit of 12 nautical miles and the exclusive economic zone extends to 200 nautical miles to the outer limit of its continental shelf. According to this treaty, if a state wants to extend its territorial water limits beyond 200 nautical miles it must prove that the sea bed is an extension of its continental shelf.
Nowadays maps are drawn up with the aid of highly sophisticated technological instruments that can discover facts which may be different from what is expected: some areas are shallower or deeper than expected. These data are vitally important to establish a nation’s sovereignty over territorial waters because the continental margin comprises the submerged prolongation of the land mass of the coastal State, and consists of the seabed and subsoil of the shelf, the slope and the rise and even the thickness of sedimentary rocks. The only area that will remain international is the Gakkel Ocean Ridge because it is a geological element that is still in the process of being formed.
Edited by Elisabetta Monistier