A critical step in improving the way we manage the earth's ecosystems is to take stock of their condition and their capacity to provide the goods and services we will need in years to come. The Pilot Analysis of Global Ecosystems (PAGE) aims to address this gap. The PAGE compares existing and new information on a global scale about the condition of five major classes of ecosystems: agroecosystems, coastal areas, forests, freshwater systems, and grasslands. The PAGE Freshwater Systems study presented here, analyzes quantitative and qualitative information and develops selected indicators of the condition of the world's freshwater systems. The condition is defined as the current and future capacity of the systems to continue providing the full range of goods and services needed or valued by humans. Specifically the study looks at measures that show the degree of human intervention in the hydrological cycle and what we know concerning three important goods and services provided by freshwater systems: water, food, and biodiversity. These goods and services were chosen partly on the advice of a wide range of freshwater experts and partly because of data availability. Results from the PAGE analysis show that human activities have severely affected the condition of freshwater systems worldwide. Even though humans have increased the amount of water available for use with dams and reservoirs, more than 40 percent of the world's population lives in conditions of water stress. This percentage is estimated to grow to almost 50 percent by 2025 . Surface and groundwater is being degraded in almost all regions of the world by intensive agriculture and rapid urbanization, aggravating the water scarcity problem. In addition, lack of access to clean water continues to be a leading cause of illness and death in much of the developing world. Food production from wild fisheries has been affected by habitat degradation, overexploitation, and pollution to a point where most of these resources are not sustainable without fishery enhancements. Finally, the capacity of freshwater ecosystems to support biodiversity is highly degraded at a global level, with many freshwater species facing rapid population declines or extinction.