Additionally, global warming poses a severe threat (Figures 1 and 2). Observational records and climate projections provide abundant evidence that freshwater resources are vulnerable and have the potential to be strongly impacted by climate change, with wide-ranging consequences for human societies and ecosystems. It affects the function and operation of existing water infrastructure (reservoirs, structural flood defenses, and urban drainage and irrigation systems) as well as water management practices. The adverse effects of climate change on freshwater systems also aggravate the impact of other stresses such as population growth, changing economic activity, changes in land use and urbanization. Globally, demand for water will grow in the coming decades, primarily due to population growth and increasing affluence; on a regional level, large changes in demand for irrigation water as a result of climate change are expected. Therefore, the provision of a water supply and sanitation, securing food for growing populations and maintaining ecosystems are all enormous challenges.