WEF Nexus in the Context of Climate Change

Seoyoung Kwon
Aug 11
10 min read

Solar-powered irrigation, hydropower reservoirs supplying water to agriculture, and crops grown for bioenergy may appear to belong to different sectors. In practice, however, they all depend on the same interconnected systems.

Water, Energy and Food.

A decision made in one of these systems can create consequences for the others. Producing more food may require more irrigation water and energy. Increasing hydropower generation can affect the timing and availability of water downstream. Expanding bioenergy crops can create competition for land and water that could otherwise be used for food production.

As climate change places growing pressure on water availability, food production, energy systems and ecosystems, understanding these interconnections is becoming increasingly important. The WEF nexus provides a way to look beyond individual sectors and consider how decisions can strengthen, or undermine the resilience of the wider system

In this blog, we will explore the concept of the Water–Energy–Food Nexus, commonly referred to as the WEF Nexus.

What is the WEF Nexus?

The meaning of the word nexus helps explain the concept:

Nexus [/ˈnek.səs/]: an important connection between the parts of a system or a group of things (Cambridge Dictionary)

The WEF nexus is an approach to understanding and managing the interdependencies between water, energy and food systems.

Water is needed to produce food and generate many forms of energy. Energy is required to pump, treat and distribute water and to produce, process, store and transport food. Food production, in turn, influences water demand, energy use, land use and ecosystem health.

Source: Future Earth, https://futureearth.org/networks/global-research-networks/water-energy-food-nexus/ — **Source:** Future Earth, https://futureearth.org/networks/global-research-networks/water-energy-food-nexus/

Because these systems are interconnected, decisions made within one sector can create trade-offs or synergies elsewhere.

For example, expanding irrigation may improve food production but increase pressure on water resources and energy demand. On the other hand, using renewable energy to power efficient irrigation systems could reduce reliance on fossil fuels while supporting agricultural production, provided that water withdrawals remain sustainable.

The purpose of nexus thinking is therefore not simply to make each sector more efficient on its own. It is to support more coherent planning and decision-making across sectors.

FAO describes the nexus in terms of understanding and managing competing demands across water, energy, food systems and ecosystems, while recognising both the trade-offs and opportunities created by decisions in different sectors.

Impacts of Climate Change on the Water, Energy, Food, and Ecosystem

Climate change is placing growing pressure on each component of the WEF Nexus. Rising temperatures, changing rainfall patterns and more frequent and severe extreme weather events can affect water availability, the reliability of energy systems, food production and the health of ecosystems.

Since the early 2010s, greater attention has been given to explicitly incorporating ecosystems into the WEF Nexus, recognising that healthy ecosystems underpin water, energy and food security while also being affected by decisions made across these sectors.

This expanded approach is commonly referred to as the Water–Energy–Food–Ecosystems (WEFE) Nexus.

Water

Climate change is altering the hydrological cycle, affecting when, where and how much water is available.

Human-induced climate change, as well as naturally occurring climate drivers such as El Niño and La Niña, has a major effect on water. Higher temperatures can increase evapotranspiration, while changing precipitation patterns can alter river flows, groundwater recharge and seasonal water availability.

Source: https://www.bbc.com/news/articles/cy4dgp1p3p1o

Droughts can intensify water scarcity, while heavy rainfall and floods can place additional pressure on water infrastructure and water quality.

For example, In parts of East Africa, there were five failed rainy seasons in a row between 2020 and 2022, as the region suffered its worst drought for 40 years. This displaced 1.2 million people in Somalia alone.

Climate change has made droughts like this at least 100 times more likely, according to the WWA.

Human-caused warming was also the main driver of drought in the Amazon rainforest in the second half of 2023, the WWA found. This was the region's worst drought since modern records began

Climate change can therefore affect both the quantity and quality of water resources, making water-resource planning increasingly complex.

Energy

Climate change is placing growing pressure on the reliability and resilience of energy systems.

Changes in rainfall and river flows can affect hydropower generation, while rising temperatures can increase electricity demand for cooling. Extreme weather events can also damage energy infrastructure and disrupt energy supply.

Recent events have shown how these risks can affect energy systems in practice. In 2022, heatwaves in Europe increased cooling demand and contributed to higher electricity prices, while Hurricane Ian damaged electricity networks in the United States and Cuba. Flooding in Pakistan also damaged power infrastructure, and droughts and floods disrupted the supply of critical minerals used in energy systems.

**Hurricane Ian has knocked out power across all of Cuba, leaving 11 million people without electricity, after it slammed into the island's western tip.**

Source: SkyNews https://news.sky.com/story/hurricane-ian-leaves-11-million-in-cuba-without-electricity-as-it-heads-towards-florida-12706700

Building climate-resilient energy systems is therefore increasingly important for maintaining energy security and supporting the transition to cleaner energy.

Food

Food production is highly dependent on temperature, rainfall and water availability, making it particularly vulnerable to climate change.

More frequent droughts, floods and heatwaves can damage crops, reduce agricultural productivity and increase irrigation demand, while changing temperatures can alter growing seasons and the areas suitable for particular crops. Climate change can also affect livestock through heat stress and changes in feed and water availability, while warmer conditions can influence agricultural pests and diseases.

These impacts extend beyond agricultural production to food security.

The Intergovernmental Panel for Climate Change (IPCC) states with high confidence that 'observed climate change is already affecting food security through increasing temperatures, changing precipitation patterns, and greater frequency of some extreme events.' FAO also identifies climate extremes as a major driver of food insecurity, particularly where climate pressures interact with economic shocks, conflict and disruptions to food supply chains.

Key concepts related to food security exists 'when all people, at all times, have physical and economic access to the sufficient, safe and nutritious food which meets their dietary needs and food preferences for an active and healthy life'.

The IPCC details the four components of food security.

Availability depends on the production of food and its storage, processing, distribution and exchange.
Accessibility involves the ability to obtain food, including purchasing food at affordable prices.
Utilisation is related to the nutrient composition of food, its preparation and the overall state of health, all affected by food safety and quality.
Stability concerns people's ability to access and use food in a steady way.

The IPCC has concluded that observed climate change is already affecting food security through rising temperatures, changing precipitation patterns and increases in some extreme events. Climate extremes are also recognised as an important driver of acute food insecurity, particularly in already vulnerable communities.

Projected changes in crop yields provide an indication of how these climatic pressures may translate into future food-security risks. Modelling presented by Our World in Data shows that the impacts vary considerably by crop and location.

Maize is particularly vulnerable to warming, with global yields projected to decline by approximately 6.4% under a low-warming scenario and by around 24% under an extreme high-warming scenario, in the absence of adaptation. By contrast, projected global impacts on wheat, rice and soybean are smaller or, in some scenarios, positive because of differences in temperature sensitivity and the effects of CO₂ fertilisation.

These differences are particularly relevant to food security because climate-related yield losses are not evenly distributed. Tropical and subtropical regions are generally expected to experience greater adverse impacts, while crops such as maize, millet and sorghum, important staples in many low-income and food-insecure countries, are particularly vulnerable. More frequent drought, flooding and waterlogging may also increase variability in agricultural production and contribute to greater food-price volatility.

Ecosystem

Climate change is altering the structure and functioning of ecosystems around the world. Rising temperatures, changing rainfall patterns and more frequent extreme events can shift habitats, change the distribution of plant and animal species, and place additional pressure on biodiversity. These impacts can be especially severe in sensitive environments such as mountains, wetlands, rivers and lakes.

Climate change can also disrupt ecological connectivity and ecosystem services. Changes in vegetation, water temperature, river flows and glacier retreat can affect species composition, aquatic habitats and the ability of ecosystems to regulate water, support soils and sustain biodiversity.

These impacts are important in the context of the WEFE Nexus because healthy ecosystems underpin water availability, food production and wider resource security. As ecosystems become degraded or less resilient, pressures can therefore spread across the other components of the nexus.

While these impacts can be described separately, they rarely occur in isolation. Water, energy, food and ecosystems are closely interconnected, meaning that a climate impact affecting one component can create cascading effects across the wider system. A change in water availability, for example, can affect energy production and agriculture, while pressures on ecosystems can further influence water quality and food production.

Why Does the Nexus Approach Matter in the Context of Climate Change?

Water, energy, food and ecosystems are closely interconnected, meaning that a climate impact affecting one component can create cascading effects across the wider system.

A decline in water availability, for example, can affect agricultural production and hydropower generation. Changes in agriculture can increase or reduce demand for water and energy. Degraded ecosystems can affect water quality, soil productivity and the resilience of food-production systems.

This is where the WEFE Nexus becomes particularly relevant to climate change.

Rather than asking only how climate change affects individual sectors, a nexus approach also asks,

How do those impacts interact, and how might a response in one sector affect the others?

Source: FAO, https://www.fao.org/land-water/water/agricultural-water-management/

In the case of drought, lower rainfall can reduce surface-water availability and increase dependence on groundwater for irrigation. Pumping more groundwater requires additional energy. Higher pumping costs can increase agricultural production costs, while excessive abstraction can further deplete aquifers. At the same time, lower water availability may affect hydropower generation.

Cross-sector Perspective on Groundwater Pumping

The introduction of affordable groundwater pumps has transformed irrigated economies and now underpins the food security of countries, such as China, India and Pakistan. However, groundwater pumping has accelerated the depletion of water resources and aquifers. Food production has become increasingly vulnerable to energy prices, often resulting in the farmers’ dependency on energy subsidies.

At the same time, farmers are left with little choice but to pump water, as services by public irrigation agencies are often poor and unreliable. The solution commonly advocated is to revise tariff and metering systems and to improve the technical efficiency of pumps. Looking at the problem from a Nexus perspective can help us to understand the wider implications for water, energy and food, and broaden the scope of interventions to include water demand management, investment frameworks for public funding for improved surface irrigation, groundwater management, irrigation technologies, agricultural practices, as well as food procurement and trade policies (e.g. Swain and Charnoz 2012). These interventions are likely to have an impact on the drivers and pressures that have led to overpumping in the first place.

Source: FAO, https://openknowledge.fao.org/server/api/core/bitstreams/86fe97cc-4a38-4511-a37f-8eb8ea8fe941/content

Agriculture provides one of the clearest examples of the interdependence between water, energy and food. It accounts for approximately 72% of global freshwater withdrawals, making food production central to efforts to address water scarcity and improve water-use efficiency.

Water is required for crop production, livestock, fisheries and food processing, while energy is needed to pump and distribute irrigation water, operate agricultural machinery, produce inputs, and process, store and transport food. Agricultural decisions can therefore affect not only food security, but also water availability, energy demand and ecosystem health.

Groundwater irrigation illustrates these connections particularly clearly. Affordable pumps have supported agricultural production and strengthened food security in many countries. However, intensive pumping can also accelerate groundwater depletion and make farmers increasingly dependent on electricity or fuel prices. Policies designed to support agricultural production, such as energy subsidies for pumping, may therefore unintentionally encourage unsustainable water use.

The FAO report uses this example to show why interventions must consider water demand, energy pricing, irrigation services, groundwater management and agricultural practices together

Similarly, efficient irrigation technologies may reduce the amount of water applied to individual fields, but they do not automatically reduce overall water withdrawals. Lower pumping costs or higher productivity may encourage farmers to expand irrigated areas or cultivate more water-intensive crops.

The Nexus approach considers irrigation technology alongside water-allocation rules, crop choices, energy requirements, farmer incentives and basin-level resource limits. By examining these relationships together, decision-makers can identify trade-offs and develop solutions that support food production without undermining long-term water security or ecosystem health

Source: https://uploads.water-energy-food.org/Session-1-presentation.pdf

The WEFE Nexus and Climate Action

Benefits of Nexus Approach
❶	Reducing sectoral trade-offs Avoid or limit negative externalities
❷	Enhancing resource efficiency Solutions designed to address multiple challenges simultaneously
❸	Political benefits Increased political legitimacy, political stability
❹	Leverage synergies towards overarching development goals

Nexus thinking can also support both climate change adaptation and mitigation.

For adaptation, integrated planning can help governments, communities and businesses respond to drought, changing rainfall patterns, floods and other climate-related risks without transferring vulnerability from one sector to another.

For mitigation, nexus approaches can help identify opportunities to reduce greenhouse gas emissions through measures such as renewable energy, energy-efficient water systems, resource recovery and more efficient agricultural practices.

Importantly, however, even a measure designed to support climate action can create new pressures elsewhere if these interconnections are overlooked.

The value of the WEFE Nexus therefore lies not in providing one universal solution, but in encouraging a broader question, "How can we respond to climate change in ways that strengthen water, energy and food security while protecting the ecosystems on which all three depend?"

Original author: Sangeun Lee

Original Korean publication: JHSUSTAIN, 15 March 2023

Translated & Updated: Seoyoung Kwon (seoyoungkwon@jhsustain.com)

References

Food and Agriculture Organization of the United Nations (FAO). 1996. Rome Declaration on World Food Security and World Food Summit Plan of Action. Rome: FAO.
Food and Agriculture Organization of the United Nations (FAO). 2014. The Water–Energy–Food Nexus: A New Approach in Support of Food Security and Sustainable Agriculture. Rome: FAO.
Food and Agriculture Organization of the United Nations (FAO). n.d. Water–Energy–Food Nexus. Land and Water Division.
FAO, IFAD, UNICEF, WFP and WHO. 2018. The State of Food Security and Nutrition in the World 2018: Building Climate Resilience for Food Security and Nutrition. Rome: FAO.
Hoff, H. 2011. Understanding the Nexus: Background Paper for the Bonn 2011 Conference – The Water, Energy and Food Security Nexus. Stockholm: Stockholm Environment Institute.
International Energy Agency (IEA). 2022. Climate Resilience for Energy Security. Paris: IEA.
Intergovernmental Panel on Climate Change (IPCC). 2019. Climate Change and Land: An IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse Gas Fluxes in Terrestrial Ecosystems. Geneva: IPCC.
Napoli, A., Matiu, M., Laiti, L., Barbiero, R., Bellin, A., Zardi, D. and Majone, B. 2025. “Review on Climate Change Impacts on the Water–Energy–Food–Ecosystems (WEFE) Nexus in the North-Eastern Italian Alps.” Climatic Change, 178, 41.
World Economic Forum. 2011. Water Security: The Water–Food–Energy–Climate Nexus. Washington, DC: Island Press.
World Meteorological Organization (WMO). 2023. State of the Climate in Africa 2022. Geneva: WMO.
World Weather Attribution. 2023. Human-Induced Climate Change Increased Drought Severity in Southern Horn of Africa.