Providing the water needed to produce food for more than 9 billion people by 2050 seems simple: agriculture must produce more food with less water. However, three complex issues are involved: First, water, food production and rural development do not have a simple correlation. Second, there are interactions between processes at local, basin and global scales. Third, change involves people in complex networks of institutions. The Challenge Program on Water and Food brings together agriculturalists, hydrologists and development specialists in a global-to-local programme that focuses on change through institutions. We believe that this scale, complexity and involvement are necessary to deliver plausible change.

Providing the water needed to produce food for more than 9 billion people by 2050 seems simple: agriculture must produce more food with less water. However, three complex issues are involved: First, water, food production and rural development do not have a simple correlation. Second, there are interactions between processes at local, basin and global scales. Third, change involves people in complex networks of institutions. The Challenge Program on Water and Food brings together agriculturalists, hydrologists and development specialists in a global-to-local programme that focuses on change through institutions. We believe that this scale, complexity and involvement are necessary to deliver plausible change.

Global challenges have exacerbated a search for solutions to poverty and environmental degradation. Integration it was argued would help address the twin challenge. Integrated Water Resources Management (IWRM) was supposed to be that magic bullet and was embraced by scientists because of the clinical efficiency with which it argued for integrated analysis of sectors and resources and of systems and scale conditions. This paper argues that effective implementation of the Water-Energy-Food (WEF) Nexus can be supported by robust science. The corollary that robust science automatically leads to effective implementation is not always known to be true. The nexus approach sheds light on the challenges of implementation by introducing concepts of trade-offs and thresholds and consequently emphasizes the importance of transdisciplinary approaches to sustainable development. This paper reviews the results of recent research to offer tentative answers to the following questions: (a) Why is the governance dimension important to undertake an integrated analysis of water-energy-food challenges? (b) What does the nexus approach connote in normative and institutional terms? (c) What does implementation mean in nexus terms? (d) How can we establish if the nexus approach is an improvement over business as usual? and (e) What tools are available that would enable translation of results of scientific research to create an evidence base that would enable decision makers to act in support of sustainable development?

Water scarcity is already a reality. More food will be required for a growing and wealthier and urbanized population that will put more pressure on water resources. With several water-related limits reached or breached - groundwater decline, shrinking rivers and threatened fisheries - we must ask, 'Will there be enough water to grow enough food? It is possible to produce the food needed, but if present practices continue it is not probable that we will solve the many poverty and environmental challenges confronting us. To share a scarce resource and to limit environmental damage in the face of climate change, it is imperative to limit future water use. Important pathways to growing enough food with limited water are to increase productivity of water in irrigated and rainfed areas, improve water management in low-yielding rainfed areas, and to consider our own food consumption patterns. In pockets of poverty in Sub-Saharan Africa and Asia, expanding access to water through a range of water management solutions holds the key to food security and poverty reduction. For sustainable water use, water managers must consider agriculture as an ecosystem and how other ecosystem services are impacted through water. These actions will require serious changes in how we think about water and food, and how we govern water and land resources.

Water scarcity is already a reality. More food will be required for a growing and wealthier and urbanized population that will put more pressure on water resources. With several water-related limits reached or breached - groundwater decline, shrinking rivers and threatened fisheries - we must ask, Will there be enough water to grow enough food? It is possible to produce the food needed, but if present practices continue it is not probable that we will solve the many poverty and environmental challenges confronting us. To share a scarce resource and to limit environmental damage in the face of climate change, it is imperative to limit future water use. Important pathways to growing enough food with limited water are to increase productivity of water in irrigated and rainfed areas, improve water management in low-yielding rainfed areas, and to consider our own food consumption patterns. In pockets of poverty in sub-Saharan Africa and Asia, expanding access to water through a range of water management solutions holds the key to food security and poverty reduction. For sustainable water use, water managers must consider agriculture as an ecosystem and how other ecosystem services are impacted through water. These actions will require serious changes in how we think about water and food, and how we govern water and land resources.

With reference to the world.

Water scarcity is already a reality. More food will be required for a growing and wealthier and urbanized population that will put more pressure on water resources. With several water-related limits reached or breached - groundwater decline, shrinking rivers and threatened fisheries - we must ask, 'Will there be enough water to grow enough food? It is possible to produce the food needed, but if present practices continue it is not probable that we will solve the many poverty and environmental challenges confronting us. To share a scarce resource and to limit environmental damage in the face of climate change, it is imperative to limit future water use. Important pathways to growing enough food with limited water are to increase productivity of water in irrigated and rainfed areas, improve water management in low-yielding rainfed areas, and to consider our own food consumption patterns. In pockets of poverty in Sub-Saharan Africa and Asia, expanding access to water through a range of water management solutions holds the key to food security and poverty reduction. For sustainable water use, water managers must consider agriculture as an ecosystem and how other ecosystem services are impacted through water. These actions will require serious changes in how we think about water and food, and how we govern water and land resources.