From Ancient Egypt to today’s California, human societies have strongly relied on access to fresh water resources, which is essential to support livelihoods and provide favorable conditions for socio-economic growth. Over centuries, humans have increasingly altered the hydrological regime by: i) building dams and reservoirs to accumulate water storage, ii) diverting water flows to supply cities, industries and agriculture, iii) changing river basin characteristics through deforestation, urbanization, and drainage of wetlands.
More recently, the hydrological regime has also been (indirectly) influenced by the alteration of the regional or global climate caused by greenhouse gas emissions and land cover changes. While societies have significantly shaped the hydrological regime, the hydrological regime in turn has shaped societies. Individuals, communities and institutions continuously adapt to hydrological change through a combination of spontaneous processes, such as migration, and formal responses, including changes in water governance and allocation. Hence, while much scientific progress has occurred from Ancient Egypt to today’s California, these reciprocal effects and mutual feedbacks between social and hydrological systems – along with climate change in a globalized and highly interconnected world – can generate unexpected water crises and keep challenging the development of sustainable policies of water management. This seminar addresses these points by describing both scientific advances and remaining puzzles in the study of dynamic human-water systems in a rapidly changing planet.