This publication presents case studies that illustrate the strong links and inter-dependencies between water, food and energy, from the perspective of a range of organisations worldwide. It was produced to inform discussions of the High-Level Panel on the Water, Food and Energy Nexus, held during the 6th World Water Forum 2012. The forum highlighted the need to integrate strategies on water, food and energy and increase resource productivity, as well as improve grassroots participation for sustainable development.

Case studies presented in the report addressed policy processes for ensuring water, food and energy security in African countries, issues associate with management of the Machángara River Basin in South America, drip irrigation in India, dam building in South-East Asia, and irrigation and hydropower in Asia.

Each case study outlines the background and how the case relates to the nexus between water, food and energy; objectives and a summary of actions taken; and results including lessons learnt.

This report outlines the first coherent strategy drawn up by the UN to address dryland management, taking into account environmental concerns and the well-being of dryland communities. It examines the relationship between drylands and climate change, food security and livelihoods, and highlights ways in which the UN is working to mainstream drylands into policymaking processes.

Climate change is already having an impact on crop yields and nutrition in areas that rely on rain-fed agriculture, according to the report, and these impacts will intensify by 2020 in parts of Sub-Saharan Africa, Asia and Latin America. The impacts of climate change may be most pronounced in Sub-Saharan Africa and South Asia, suggesting that those already vulnerable will be affected the most.

A key message is that the international community has an opportunity to address the underlying causes of dryland degradation. The report concludes that global cooperation must be intensified if the ten-year strategic plan of the UN Convention to Combat Desertification — whose aim is to tackle desertification and degradation — and the Millennium Development Goals are to be achieved.

This paper aims to assess the suitability of using self-reported food security indicators to assess the welfare impact of the 2007–2008 global food crisis. It tests the usefulness of data from the Gallup World Poll (GWP) — a survey of self-reported food insecurity conducted before, during, and after the crisis — as an alternative to modelling estimates produced by the UN Food and Agriculture Organization, the US Department of Agriculture, and the World Bank.

The results suggest that although trends vary across countries, global self-reported food insecurity fell between 2005 and 2008, with the most reasonable estimate indicating 60–250 million fewer food-insecure people over that period. This trend contrasts with what was estimated by modelling-based methods. It is driven by rapid economic growth and limited food price inflation in China and India, among other heavily populated countries.

This perspective article highlights some of the most proactive and innovative ideas related to water management and policy, including the concepts of 'virtual water' — water used to produce food that is traded — and the 'water footprint'. The authors discuss a range of issues, including water pricing, sustainability, water quality and alternative resources.

The one bright note in global warming is seemingly that higher carbon dioxide levels will make food crops grow faster. More crops should equal more food. But, as this feature article emphasises, the story is not that simple.

Initial tests have shown that plants grown in high carbon dioxide environments could be less nutritious — with lower protein levels and a different type of protein produced. Other scientists have found a drop in key micronutrients such as chromium, selenium and zinc in high carbon dioxide environments.

Mitigating these changes can involve increasing nitrogen levels to offset protein deficiency, although not all scientists agree on this.

What is clear is that there is very little research in this area and past studies have only looked at carbon dioxide concentrations of 550 parts per million, which is lower than levels predicted by the end of this century.