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Nexus Concept

27 Mar 14

The Nexus Approach vs IWRM - Gaining Conceptual Clarity

The key difference between the Nexus and IWRM is that IWRM starts with the water resource when considering the interrelationships between water, food and energy. In an idealized form the Nexus approach seeks to look at all three elements as an interrelated system. A policy paper by UNSGAB.

This comparison of the Integrated Water Resource Management (IWRM) apporach with the nexus approach shows that not one is replacing the other. The IWRM and Nexus approaches are very closely related. The ultimate objectives of both are to promote better resource use to allow societies to develop in ways which are sustainable – environmentally, socially and economically.


Today it has become commonplace to discuss the linkages between water, food and energy security in terms of a nexus with some suggestions that IWRM has now been super-ceded by Nexus thinking. In fact the two concepts are closely related and although the nexus terminology may be relatively new the fundamental idea behind it is not. Both IWRM and the Nexus are based on the view that segmented sectorial planning and decision making is likely to lead to unsustainable development pathways and inefficiencies in the development of resources and their allocation between uses and users. Therefore, both concepts see the need to promote greater co-ordination between inter-linked resource producing and consuming sectors and to clearly recognize the consequences of decisions made in one sector for the other sectors. Both concepts also have the same emphasis on changing the way policy and decision making occurs in order to improve human welfare and social equity, allow sustainable growth and protect essential environmental resources. They are both part of the general approach to sustainable development and today underpin work on the Green Economy and Green Growth.

Integrated Water Resource Management (IWRM)


is the United Nations General Secretary’s Advisory Board on Water and Sanitation. To assist the international community, the United Nations Member States and the international organizations to achieve the MDG related to water and sanitation, United Nations Secretary-General Kofi Annan announced the establishment of UNSGAB on occasion of World Water Day 2004. The Board, inter alia, focus their work on: help to mobilize resources for water and sanitation towards achievement of MDGs and JPOI; publicly mobilize support and advocate for actions and ensure political visibility; assess progress made towards the water and sanitation goals; and advocate for improving the capacity of Governments and the international system.


Integrated Water Resources Management is an approach set forth in Agenda 21 (1992) and as such it can be considered to be the water element within the broader sustainable development framework. Agenda 21, which devoted a chapter to the critical links between effective water management, food production and sustainable rural development, focused on the use of resources to best support social equity, economic development and environmental objectives (1). This focus is also at the heart of the Nexus approach.

As its name would suggest IWRM adopts a water sector lens and takes improved water resources management as its point of departure. In part IWRM involves the need for co-ordinated planning and decision making within the water sector to account for the linkages within the natural system between upstream and downstream, surface and ground water uses. However, the concept also reaches out of the water box to look at the relationships within economic and social systems which have implications for resource use. In its paper on IWRM the Global Water Partnership (GWP) was explicit in its recognition that “national energy and food policies may have a profound impact on water resources-and vice versa” (2).

GWP defined IWRM as a process which promotes the coordinated development and management of water, land and related resources in order to maximise economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems and the environment. However, the diagram employed to illustrate the need for cross-sectorial integration shows quite clearly the water-centric nature of IWRM and this is the key difference between the IWRM and the Nexus approaches. Whereas IWRM is predominantly concerned with the efficient(most effective) use of the limited water resource base, Nexus thinking stresses that “by addressing externalities across sectors, overall resource use efficiency can be improved” (3).

Water, Energy and Food Security Nexus

Under the IWRM rubric much attention had been focused on the need to consider land and water management in an integrated way in order to help ensure both water and food security. What was relatively new was the general realization that energy use and security also had to have a place in co-ordinated management approaches. It is of course true that for many years specific cases illustrating the linkages between water, food and energy have been cited, such as the impact of subsidised energy prices for irrigated agriculture on the demand for water. However, with concerns over climate change and the search for low carbon alternative energies it was increasingly acknowledged that the relationships between water, food and energy went beyond such specific examples and needed to be treated in a more holistic way.

Although there were academic studies on the complex interrelated problems of water, energy and food security, it was not until 2011 that nexus approaches rose up the international political agenda. The World Economic Forum, for example, addressed the issue in its 2011 Water Security Report (4) and in November 2011 more than 550 people representing diverse stakeholder groups gathered at a conference in Bonn, Germany, to explore the ways that the nexus approach might be employed to achieve sustainability and promote the transition to a green economy. The results and messages of this conference were a specific German contribution to the UN Conference on Sustainable Development “Rio2012”.

Basically the nexus approach is a decision making framework which employs systems thinking to identify cross-sectorial impacts (externalities), explore feasible trade-offs and help policy makers achieve greater policy coherence as efforts are made to move development pathways which are resource efficient, equitable and sustainable. It is an approach which can be applied at all levels of governance from the local to the international.

As Bazilian et al (2011) (5) point out in reality the approach taken to the nexus normally depends upon the perspective of the policy maker. So, for example, if a water perspective is adopted then food and energy systems are users of the resource, but from a food perspective energy and water are inputs. In a sense IWRM, when considered in all its dimensions, can be seen as the nexus approach using a water perspective. However, to achieve the nexus objective of improving overall resource efficiency there is a need to develop much more robust analytical tools to ensure that all the impacts and trade-offs are clearly identified; this is not of course a trivial task especially given the uncertainties about the economic, social and environmental futures.


The IWRM and Nexus approaches are very closely related. The ultimate objectives of both are to promote better resource use to allow societies to develop in ways which are sustainable (environmentally, socially and economically). They both start by identifying, fragmented, un- coordinated sectorial decision making as a key problem leading to wasteful, inefficient resource use which is ultimately unsustainable and then they both seek to develop processes/frameworks which will promotes integration across sectors.

The key difference between them is that IWRM starts with the water resource when considering the interrelationships between water, food and energy. In an idealized form the Nexus approach seeks to look at all three elements as an interrelated system but data and modelling constraints make this a hugely challenging task. In reality nexus thinking normally start from one perspective and the fact that this could be energy or food security makes the concept appear much more relevant to these sectors than IWRM.



Integrated Water Resources in Practice: Better water management for development, edited Roberto Lenton & Mike Muller.


Global Water Partnership Technical Advisory Committee, Integrated Water Resources Management, TAC Background papers, No 4, 2000


Background paper for the Bonn 2011 Conference, The water, energy and food security nexus


World Economic Forum, 2011, Water Security: The Water-Food-Energy-Climate Nexus Island Press, Washington


Brazilian, M., et al, Considering the energy, water and food nexus: Towards an integrated modelling approach, Energy Policy (2011)

Related Resources


IWRM and the Water, Energy and Climate Nexus

Presentation held by Nathan Cammerman In September 2009 at the 12th International Riversymposium in Brisbane, Australia

Related News

World Water Day 2014

“In the water sector, the food-energy-water nexus is slowly replacing the concept of Integrated Water Resources Management, “ says Jeremy Allouche, member of the IDS Water Justice Programme and the STEPS Centre.

Further Reading

20 Mar 12

UN Secretary General Ban Ki-moon highlights “nexus approach” while urging that environmental, social and economic aspects of development be integrated

08 Nov 11

The water, food, energy nexus approach puts a great deal of emphasis on increasing efficiency within production; however, it also must be applied to consumption in order to lower increasing demand from population and economic growth, according to Holger Hoff, senior research fellow at the Stockholm Environment Institute and lead author of the nexus background report for the Bonn2011 Conference.

22 Nov 11

How Human Rights Based Approaches (RBA) contribute towards better development outcomes for water, energy and food security from the perspective of governments and civil society organisations

NEXUS in the Media

16 Jun 14

The Guardian

The dramatic spike in resource use over the last two decades, particularly in the emerging economies of Brazil, Russia, India and China, has exacerbated the threat of resource scarcity. And the world’s failure to curb emissions of greenhouse gases means that the impacts of climate change will be felt strongly across food, water and energy - the three dimensions of the “nexus”. It is unsurprising there are increasing calls for innovative ways of approaching these problems. In recent years, the nexus approach has attracted significant interest from international organisations, the private sector and other global players as a way of tackling the interdependencies between water, energy and food security. The urgent need for joined up approaches to policy and practice lies at the heart of nexus thinking. It’s an approach which applies at all levels of society; from local competition over access to water for irrigation or livestock, to global connections between policy on biofuels, food and water security. - By Michael Bradshaw, Declan Conway and Hayley Leck

10 Jun 15


In this STEPS Center working paper, the authors argue that the governance of water, energy and food security has privileged control-orientated solutions

29 Mar 16

IFAD Social Reporting Blog

“Producing more food with less water and energy”

30 Mar 16

Humanitarian News

“Producing more food with less water and energy”


  • IFPRI International Food Policy Research Institute
  • WEF World Economic Forum
  • WWF World Wide Fund for Nature

Bonn2011 Nexus Conference – in the context of Bonn Perspectives

  • Bonn Perspectives

initiated by

  • BONN
  • BMZ

funded by

  • European Regional Development Fund EFRE
  • NRW Ministerin fr Bundesangelegenheiten, Europa und Medien des Landes Nordrhein-Westphalen
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