It is the understanding of the Committee that, for the purposes of this Convention, the terms "widespread", "long-lasting" and "severe" shall be interpreted as follows:
a) "widespread": encompassing an area on the scale of several hundred square kilometres; b)"long-lasting": lasting for a period of months, or approximately a season;
c) "severe": involving serious or significant disruption or harm to human life, natural and economic resources or other assets.
It is further understood that the interpretation set forth above is intended exclusively for this Convention and is not intended to prejudice the interpretation of the same or similar terms if used in connexion with any other international agreement.
Understanding relating to article II
It is the understanding of the Committee that the following examples are illustrative of phenomena that could be caused by the use of environmental modification techniques as defined in article II of the Convention: earthquakes; tsunamis; an upset in the ecological balance of a region; changes in weather patterns (clouds, precipitation, cyclones of various types and tornadic storms); changes in climate patterns; changes in ocean currents; changes in the state of the ozone layer; and changes in the state of the ionosphere.
It is further understood that all the phenomena listed above, when produced by a military or any other hostile use of environmental modification techiques, would result, or could reasonably be expected to result, in widespread, long-lasting or severe destruction, damage or injury. Thus, military or any other hostile use of environmental modification techniques as defined in article II, so as to cause those phenomena as a means of destruction, damage or injury to another State Party, would be prohibited.
It is recognized, moreover, that the list of examples set out above is not exhaustive. Other phenomena which could result from the use of environmental modification techniques as defined in article II could also be appropriately included. The absence of such phenomena from the list does not in any way imply that the undertaking contained in article I would not be applicable to those phenomena, provided the criteria set out in that article were met.
Understanding relating to article III
It is the understanding of the Committee that this Convention does not deal with the question whether or not a given use of environmental modification techniques for peaceful purposes is in accordance with generally recognized principles and applicable rules of international law.
Understanding relating to article VIII
It is the understanding of the Committee that a proposal to amend the Convention may also be considered at any conference of Parties held pursuant to article VIII. It is further understood that any proposed amendment that is intended for such consideration should, if possible, be submitted to the Depositary no less than 90 days before the commencement of the conference.
Note: These Understandings are not incorporated into the Convention but are part of the negotiating record and were included in the report transmitted by the Conference of the Committee on Disarmament to the United Nations General Assembly in September 1976 (Report of the Conference of the Committee on Disarmament, Volume I, General Assembly Official records: Thirty-first session, Supplement No. 27 (A/31/27), New York, United Nations, 1976, pp. 91-92).