Territories
States
States of necessity must have a territory. Within its territory, the state has the right to exercise jurisdiction and the functions of a state. It is a basic principle that states may not exercise or purport to exercise jurisdiction over other states. However, it may exercise jurisdiction over its own nationals.
The number of states has more than trebled since  1945. Most states are former colonies or parts of larger states which have seceded or broken up. The UN General Assembly resolution on the granting of independence to colonial territories and people in 1960 embodied the principle of self-determination as a legal right. There were very few colonial territories left which have not achieved some degree of independence or were not self-governed.
The territory within a  state includes its land, subsoil, water, land under the water, the coasts to certain limits and the air space over the land and sea.
Acquisition
Territory can be acquired in a number of ways. Occupation refers to obtaining the original title to the territory. It arises when a territory which has not been previously occupied or appropriated is occupied for the first time. Land which has not been previously subject to sovereignty may be appropriated.
Lands which are occupied by tribes and nomadic people who enjoy a social and political organization are not regarded as unowned land for this purpose. Â If there is any element of agreements or arrangements with local rulers these, then even if the land is taken by force and plantation, the acquisition is derivative rather than by original appropriation.
Recovery followed by effective occupation may be sufficient to obtain the original title. Effective occupation means the exercise of sovereignty. This implies a display of sovereignty.
Exercise of Sovereignty
What constitutes the exercise of sovereignty and its display will depend on the nature of the territory. Manifestations of territorial sovereignty may take different forms according to the conditions and place.
Sovereignty cannot be exercised continuously at all times. The level of intermittence and continuity compatible with the maintenance of sovereignty differs depending on whether the areas are inhabited or uninhabited and the type of territory involved.
The exercise of minimal sovereignty may be sufficient where other states cannot make out superior claims. This is particularly so in the case of claims of sovereignty over thinly populated or unsettled areas.
Effective occupation must be open and public and involve the continuous and peaceful display of state authority over a prolonged period. Peaceful implies es that sovereignty is accepted without protest from other states.
Evidence of state intention to exercise sovereignty is an important factor. The state with prior intention will usually have the superior claim. The date at which intention is manifested will be critical.
Prescription
Prescription is a means of acquiring territory which is not terra nullius. It may legitimize a dubious state title where there is a display of sovereignty to which other states do not object. Protests from an interested state or a dispossessed sovereign state may disrupt a prescriptive claim.
The length of time required to establish sovereignty by prescription depends on the circumstances. Sovereignty may not be based exclusively on prescription.
Generally, the continuity principles allow states to extend sovereignty over land adjacent to an area of territory outside of control, which is not under the control or sovereignty of other states.This will generally include islands.
Frontiers
Frontiers of newly independent states are to follow the frontiers of old colonial territories from which they emerged. The principles were asserted at the end of the colonial era in South America when provinces of the former Spanish empire agreed to limit their sovereignty in accordance with the limits of the old colonial boundaries and provinces. Frontiers so established may be varied by the acquiescence of one state or by effective control over the disputed areas.
Generally, action to alter frontiers by force will be unlawful. Under contemporary international law, sovereignty may not be acquired by force or conquest.
Conquest is possession taken of enemy territory by military force. It involves the actual taking over of territory with an intention to take it over.
Territory may have been lawfully acquired by conquest in accordance with the principle that applied at the relevant time. Accordingly, it may be that the particular states acquired territory historically by conquest in accordance with the earlier concepts.
Secession involves the peaceful transfer of territory from one state to another. This may be done by treaty or after cessation of possibilities.
Self-Determination
Self-determination has become a well-established principle of Customary International Law, and it is a basic principle. Self-determination requires the free and genuine expression of the will of the persons concerned.
The International Court has recognized the customary law of self-determination existing in the context of non-self-governing territories and people subject to alien subjugation, domination and exploitation. However, it is not clear to what extent self-determination may be exercised by distinct ethnic and religious groups within an existing sovereign independent state.
International Court has taken the view that there is no right of cessation provided that the central authorities respect the internal self-determination of the ethnic group.
States may increase the geographic area by accretion. This is the addition to the territory over time by alluvial deposits and geographical factors. Avulsion is a sudden violent change in the territory to something such as volcanic action.
New states may achieve independence in accordance with principles of self-determination. In this case, sovereignty transfers from another state over the territory concerned is acquired by the new sovereign. Different theories may apply in respect of the basis of sovereignty in such cases.
Arctic
The Arctic is incapable of occupation in the same manner as other places. Several states exercise various sovereign rights over the areas comprising the Arctic. Denmark exercises jurisdiction over Greenland.
Arctic states have adopted certain environmental treaties guaranteeing sustainable development. This includes the Arctic environmental protection strategy. The Arctic Council has dealt with these matters with this since 1997.
The requirement for an Arctic environmental impact assessment was adopted under the  ALTA. The Arctic region continues to be somewhat disputed. It has significant resources, and a number of states lay claim to it.
Antarctica
Antarctica has equally been the subject to territorial claims. The Antarctica Convention of 1959 confirms that Antarctica is to be used exclusively for peaceful purposes.
Military activity is prohibited. A number of initiatives have been adopted regarding environmental protection, include the Madrid Protocol on Environmental Protection to the Antarctic Treaty 1991.
The Antarctic is subject to sovereignty claims by the U.K., Argentina, Chile, France, Australia, New Zealand and Norway. The claims of the first three overlap.
It has been suggested that all states should be allowed to share in the potential wealth of the continent in the same way as the deep sea bed or outer space and should be the common heritage of mankind.
The 1959 Antarctic Treaty was drawn up by states having an interest or claim in the area. It recognizes the importance of preserving the environment and requires that it be used for peaceful purposes.
The treaty placed moratoria on claims of sovereignty. The claims of sovereignty have been suspended since 1961.    No activities or actions are to take place while the treaty is in force, constituting a basis for asserting, supporting or denying a claim to sovereignty in the Antarctic.
There are 50 parties to the convention, including 28 consultative parties who meet every two years. They make recommendations on  various matters which may become binding on parties. There has been a proposal to turn Antarctica into a wilderness reserve where oil extraction, mining and exploitation would be prohibited.
This is embodied in the protocol on environment protection in the Antarctic Treaty, which has agreed upon in 1991. This is a compromise between the states wishing to follow the minerals convention and those wishing for an absolute ban on the exploitation of Antarctica.
Activity other than the mineral resources, relating to mineral resources, other than scientific research shall be prohibited. There is a provision for modification under a special procedure or by review of the conference 50 years after the protocol comes into effect.
Airspace
States are sovereign over their airspace. This includes the airspace above the land and territorial seas.
The 1919 Paris Convention on the Regulation of Aerial Navigation and the 1944 Chicago Convention on International Civil Aviation so confirms this. The Chicago Convention applies to civil aircraft but not to military, customs and police service craft.
The general principle is that aircraft require permission before flying into or over the territory of a contracting state; conditions may be imposed on the use of air space. However, the conventions allow for general permissions subject to conditions.
The International Air Service Transit Agreement relates to fly over and landing for purposes such as refuelling. It includes freedoms and traffic rights, including the
- privilege to put down the passengers, mail or cargo taken on in the territory of the state of the aircraft.
- privilege to take on passengers, mail and cargo destined for the state of nationality of the aircraft,
- privilege to take on passengers, mail and cargo destined for the territory of other contracting states,
- privilege to put down passengers, mail and cargo coming from any such territory.
The convention has been widely ratified. Most air traffic is regulated by bilateral and other multi-lateral agreements.
The International Civil Aviation Organization is an agency of the UN and is the most significant entity in the multilateral agreement. It promotes the development of civil aviation, setting standards in relation to aviation safety and environmental protection.
Outer Space
It is accepted that sovereignty does not extend up infinitely beyond the point of outer space. There is disagreement as to where this boundary occurs. It is generally assumed to be somewhere between 150 and 200 miles upward.
The UN Committee on the Peaceful Uses of Outer Space was established in 1958 and regulates activity in relation to outer space. A number of treaties and principles on state laws have been included under the committee. The basic principle is that outer space may only be used for peaceful means and that it is the common heritage of mankind.
The UN 1963 declaration on the exploration and use of outer space was followed by a series of treaties giving effect to the principles.
The exploration of outer space, including moons and celestial bodies, is to be carried out in the interests of all countries, and irrespective of their economic and scientific development. It is to be the province of all mankind.
Outer space, including the moon and celestial bodies, is not to be subject to a claim of national appropriation by claim of sovereignty, whether by occupation or by any other means. It is prohibited to establish military bases and install nuclear or other weapons of mass destruction in outer space. States must avoid harmful contamination and other adverse changes in the environment resulting from the introduction of extra-terrestrial matter.
The Outer Space Treaty has been revised by a 1979 agreement relating to the activities of states on the moon and other celestial bodies. The moon is not subject to appropriation by any state or claims of sovereignty by use, occupation or otherwise.
The agreement confirms that the states are to achieve an equitable sharing of the benefit derived from those resources having regard to the interests and needs of developing countries. The efforts of countries which have contributed directly or indirectly to the exploration of the moon shall be given special consideration.
There are treaties covering astronauts, satellites and damages caused by them falling back to earth.
A 1968 agreement on the rescue of astronauts and return of objects launched into space and the Convention on international liability for damage caused by space objects supplemented measures dealing with outer space. States are liable for damage caused by their satellites and equivalent objects falling to the ground.