> For the complete documentation index, see [llms.txt](https://docs.therisk.global/organization/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.therisk.global/organization/model/sectors.md).

# Sectors

The six sectors of the Nexus model: water, energy, infrastructure, food, health and biodiversity, and what each gives to and receives from the others.

**Where this fits:** all six sectors · Labs and Foundry (observation and modelling) · GCRI (evidence and methods) · model landing.

**In brief.** The sector hexagon places water at the top and then, clockwise, energy, infrastructure, food, health and biodiversity. Each sector page shows what that sector gives to the others, what it depends on, the teaching contexts in which it is hit first or reached through the coupling, the observatory capability that watches it, and the international frameworks that govern it. The strengths are **teaching values for a typical city-region, not measurements for any place**.

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>W · Water</strong></td><td>Irrigation, drinking water, cooling and hydropower, environmental flows; and flood and drought as hazards.</td><td><a href="/organization/model/sectors/water.md">Water</a></td></tr><tr><td><strong>E · Energy</strong></td><td>Power and fuel for pumping, cold chains, hospitals, transport and telecoms.</td><td><a href="/organization/model/sectors/energy.md">Energy</a></td></tr><tr><td><strong>I · Infrastructure</strong></td><td>Pipes, dams, grids, roads, ports and defences that carry the other sectors.</td><td><a href="/organization/model/sectors/infrastructure.md">Infrastructure</a></td></tr><tr><td><strong>F · Food</strong></td><td>Production and distribution downstream of water, energy and ecosystems; nutrition for health.</td><td><a href="/organization/model/sectors/food.md">Food</a></td></tr><tr><td><strong>H · Health</strong></td><td>Care and public health, and the workforce every other sector runs on.</td><td><a href="/organization/model/sectors/health.md">Health</a></td></tr><tr><td><strong>B · Biodiversity</strong></td><td>Watersheds, soils, pollination and coastal buffers.</td><td><a href="/organization/model/sectors/biodiversity.md">Biodiversity</a></td></tr></tbody></table>

## How the sectors were chosen

The six sectors are the smallest set that covers the interlinkages the international assessments treat together. The water-energy-food nexus (FAO, [2014](https://www.fao.org/4/bl496e/bl496e.pdf)) and the IPBES nexus of biodiversity, water, food and health (IPBES, [2024](https://www.ipbes.net/nexus-assessment)) supply five of them. Infrastructure is added as the sixth because the built networks are where most interdependency failures happen and where their costs are counted (Rinaldi, Peerenboom and Kelly, [2001](https://doi.org/10.1109/37.969131); Hallegatte, Rentschler and Rozenberg, [2019](https://openknowledge.worldbank.org/handle/10986/31805)). Climate is not a sector in the model; it is a driver that acts on all six, through the hazards of the teaching contexts.

The full set of thirty relations between the sectors is on [Coupled risk](/organization/model/coupled-risk.md).

## Sources

* FAO (2014). *The Water-Energy-Food Nexus: A new approach in support of food security and sustainable agriculture.* Rome: FAO. <https://www.fao.org/4/bl496e/bl496e.pdf>
* Hallegatte, S., Rentschler, J. and Rozenberg, J. (2019). *Lifelines: The Resilient Infrastructure Opportunity.* Washington, DC: World Bank. <https://openknowledge.worldbank.org/handle/10986/31805>
* IPBES (2024). *Summary for Policymakers of the Thematic Assessment Report on the Interlinkages among Biodiversity, Water, Food and Health (Nexus Assessment).* <https://www.ipbes.net/nexus-assessment>
* Rinaldi, S. M., Peerenboom, J. P. and Kelly, T. K. (2001). Identifying, understanding, and analyzing critical infrastructure interdependencies. *IEEE Control Systems Magazine* 21(6): 11–25. <https://doi.org/10.1109/37.969131>


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