The objective of the XIIIth World Water Congress is to enhance the world’s knowledge and raise global consciousness of the impact of global changes on water resources. The Congress will bring together wide-interest participation, exhibitions and scientific communications about our planet’s water resources. This Congress will represent an important global meeting point for open dialogue between public and private partners, between users and decision makers and between developing, emerging and developed countries. In order to contribute to this global reflection and action, the Congress will organise numerous debates, presentations and exhibitions among key water stakeholders. The interactions between water resources and global change are numerous and complex. Much is at stake for the future. The global change concept is made of three interdependent fields: The intrinsic natural variability of the environment is a permanent characteristic today as it has been in the near and the distant past. Water is a key player in this variability, acting all over the Earth’s surface as a medium of matter transport, a sculptor of landscapes and a source of life and evolution. The impact of human societies that modify their environment to their needs, particularly for crop and animal production in order to secure their food supplies. The evaluation and the integrated management of water resources represent decisive factors in these vital priorities for humanity. Current climate change, visible since approximately one century ago, and its predominantly anthropological origins today receive general consensus from the scientifi c community. Global warming, a premier instance of global change, is strongly impacting the extent of glacier and snow cover; it also has a probable effect on precipitation and water flow regimes; and on the frequency and intensity of extreme events such as floods and droughts.