The principal objective of the symposium will be to exchange recent research achievements in the use of isotopic techniques in hydrology, climate change studies, marine and terrestrial ecosystems. The symposium will be an important forum for the exchange of knowledge on the present state of marine and freshwater environments, use of isotopes in water resources investigations and management, and climate change studies. The meeting will involve leading scientists in the field of climate change and hydrology, as well as representatives from other United Nations bodies and international organizations that focus on climate change and other important rnvironmental issues.