Differently from land frontiers, which have physical limits and references for their demarcation, in the sea there are no lines which permit the establishment of visible frontiers. This peculiarity demands the adoption of conventions that are accepted by the international community. In 1982, the resolutions of the United Nations Convention on the Law of the Sea — (UNCLS) were ratified by Brazil. The UNCLS resolutions established important concepts for the regulation of sea limits, i.e. a territorial waters (MT), where the state exercises full sovereignty, including the airspace above; a contiguous zone (ZC), where the coastal state may implement customs, sanitary and control measures as well as restrain legal infractions; and an economic exclusive zone (ZEE), where the state has the sovereign right to explore, exploit, maintain and manage natural resources, whether living or non-living. From the baseline where the MT originates until the external limit of the ZEE, the coastal state exercises its rights over a 200 nautical miles (370 km) area, the so-called “jurisdictional waters”, where sovereignty is exerted in differing degrees. The UNCLS has been ratified by 152 countries. However, there are still non-adherent nations, including great powers. This fact may become a source for conflict in the future. United Nations Convention on the Law of the Sea (UNCLS) The UNCLS established a sea territory (MT) of 12 nautical miles (22 kilometers), measured from the continental base line; a contiguous zone (ZC), adjacent to the MT, which extends to a further 12 nautical miles; and an economic exclusive zone (ZEE), a 188 nautical miles strip, adjacent to the MT (including the ZC). The UNCLS established moreover that states may claim an increase in their ZEE, if certain technical criteria are complied with, to a maximum extent of 350 nautical miles (648 kilometers). Internally, in 1993, Brazil adopted the 1982 and 1988 resolutions of the UNCLS, but only in 1994, with the ratification of the 60th country, did the UNCLS enter into force. DEFENSE WHITE PAPER 45 CHAPTER 2 — THE 21st CENTURY STRATEGIC ENVIRONMENT International Treaties on the Sea, Antarctica and Outer Space