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.

This special issue brings together contributions from a wide range of specialists looking at aspects of the global water and food system and its impact on poverty.

This Brief considers the impacts of global change (in terms of climate, demography, technology, and so on), on agriculture and natural resources in developing countries, with a focus on Africa.

Conflicting demands for food and water, exacerbated by increasing population, increase the risks of food insecurity, poverty and environmental damage in major river systems. Agriculture remains the predominant water user, but the linkage between water, agriculture and livelihoods is more complex than “water scarcity increases poverty”. The response of both agricultural and non-agricultural systems to increased pressure will affect livelihoods. Development will be constrained in closed basins if increased demand for irrigation deprives other users or if existing agricultural use constrains non-agricultural activities and in open basins if agriculture cannot feed an expanding or changing population or if the river system loses capacity due to degradation or over-exploitation.

This paper analyses water availability and use within and between the Challenge Program on Water and Food basins. It describes the main features of water demand and supply in the basins and indicates where there are deficits and opportunities for development of water resources. A typology of basin water resources status uses a range of global spatial datasets. The main outcomes of basin activities on water availability are identified. Interbasin assessment of water availability is very challenging for such very large basins, due in large part to difficulties in collecting and integrating local data sets.

Major water issues in the Mekong River Basin concern not total water availability, but the impact of changed flows on ecology, fish production, access to water and food security.

Global population growth exerts stresses on river basins that provide food, water, energy and other ecosystem services. In some basins, evidence is emerging of failures to satisfy these demands. This paper assembles data from nine river basins in a framework that relates water and food systems to development. The framework provides a consistent basis for analysis of the water and food problem globally, while providing insight into specific conditions within basins. The authors find that successes occur when demand is met by increased productivity, while failure occurs when factors conspire to prevent development of land and water resources.

In 2008, the CGIAR Challenge Program for Water and Food (CPWF) was in transition from the first five years of operation to a streamlined and refocused second phase. Beginning in 2009, CPWF research-for-development engages fewer river basins and targets clearly defined ‘Basin Development Challenges’ within specific geographical areas of each basin.<br/><br/>The 2008 report summarises major research accomplishments, governance and management changes, progress in other areas (communication and capacity building) and finance.

Established in 2002, the CPWF was designed as a 15-year research-for-development program. Phase 1 ran from 2004–2008 and Phase 2 runs from 2009–2013.<br/><br/> This year’s Annual Report is structured to provide the reader with a broad overview of CPWF’s direction in Phase 2, while reporting on key activities from 2009. The report also show how Phase 1 research has been used in the design of Phase 2 and how the program will be structured and managed in Phase 2.

One of the CPWF's research approaches was to examine in detail the issues of development, poverty and water productivity in 10 river basins worldwide in the Basin Focal Projects. This Special Issue has papers from nine of these basins: the Andes system of basins in South America; the Limpopo, the Niger, the Nile and the Volta in Africa; the Karkheh in Iran; and the Ganges, the Indus, the Mekong and the Yellow in Asia. A second Special Issue of the same journal looks at cross-basin analyses.