Climate change adaptation should ideally progress through various stages: • Recognition among all basin states of the possibility of water stress in the basin • A basin-wide study, including exchange of relevant scientific and other information, to identify scenarios about the likely magnitude of the stresses over a reasonable time horizon • Agreement among all basin states, within the bounds of agreed upon uncertainty ranges, on the magnitude and geographical distribution of the stresses • Agreement on measures needed at basin and national levels • Agreement on implementation, including actions to be taken by an existing basin-wide management authority, creating a new authority, or expanding the powers of an existing authority.