> 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/scenarios/drought.md).

# Drought

Drought: the coupled risk across water, energy, food, health and biodiversity, and the applied response of the programme pillars, as a teaching context of the Nexus model.

**Where this fits:** water, energy, food, health and biodiversity · Labs, Foundry, Nexus Universe, Nexus Standards, Nexus Reports and Risk Academy · the Nexus Consortium · the whole programme year · teaching context.

> Low river flows cut irrigation, cooling water and hydropower at once; food prices, nutrition and ecosystems follow.

**In brief.** In this teaching context water is hit first. 5 of the six sectors are in play through 10 of the fifteen relations, a coupling of 0.68 of the whole system, and the teaching cascade amplifies the initial shock ×2.89. On the response side, 6 of the six pillars apply, with 18 of the eighteen handoffs in play and 17 feedback loops closed. All sector values are **teaching values for a typical city-region, not measurements for any place**; the applications are illustrative and the cited values are published benchmarks, not forecasts.

<figure><picture><source srcset="https://2655483226-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FEQtittnb4JJQ2YOtd2tk%2Fuploads%2Fgit-blob-845190300bb44dddd43021ede154733d38bf0431%2Fnexus-duo-drought-dark.svg?alt=media" media="(prefers-color-scheme: dark)"><img src="https://2655483226-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FEQtittnb4JJQ2YOtd2tk%2Fuploads%2Fgit-blob-3f250a1ccd39a4a5f245250e599e7012ee027b5e%2Fnexus-duo-drought-light.svg?alt=media" alt="Two hexagons for drought. Left, coupled risk: water is hit first; 5 of the six sectors (water, energy, food, health and biodiversity) are in play through 10 of the fifteen relations, and the teaching cascade amplifies the initial shock 2.89 times. Right, applied response: 6 of the six programme pillars apply (Labs, Foundry, Universe, Standards, Reports and Academy), with 18 of the eighteen handoffs between them in play and 17 feedback loops closed; the cited headline value is $7.1T net benefits. Underneath, the eight phases of the programme year in which handoffs happen."></picture><figcaption><p><strong>Coupled risk, applied response: drought.</strong> Left: teaching values for a typical city-region, not measurements. Right: illustrative applications and the measure each pillar answers for; values are published benchmarks (Global Commission on Adaptation, Adapt Now, 2019), not forecasts. Source: the sectors and pillars model published on the GCRI, GRF and GRA home pages, vendored and hash-pinned in tools/figures/vendor/nexus-model. As of 2026-10-21.</p></figcaption></figure>

<details>

<summary>Figure data (text alternative)</summary>

| Element                 | Kind             | Description                                                                                                                                                         | Value                         |
| ----------------------- | ---------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------- |
| Water and Energy        | Relation in play | Water to energy: cooling water and hydropower (0.6); Energy to water: pumping and treatment (0.5)                                                                   | 0.55                          |
| Water and Food          | Relation in play | Water to food: irrigation (0.8); Food to water: withdrawals and runoff (0.3)                                                                                        | 0.55                          |
| Water and Health        | Relation in play | Water to health: drinking water and sanitation (0.7); Health to water: utility workforce (0.2)                                                                      | 0.45                          |
| Water and Biodiversity  | Relation in play | Water to biodiversity: environmental flows (0.6); Biodiversity to water: watershed regulation (0.5)                                                                 | 0.55                          |
| Energy and Food         | Relation in play | Energy to food: fertiliser, machinery and cold chains (0.5); Food to energy: bioenergy feedstock (0.2)                                                              | 0.35                          |
| Energy and Health       | Relation in play | Energy to health: hospital power (0.5); Health to energy: grid workforce (0.2)                                                                                      | 0.35                          |
| Energy and Biodiversity | Relation in play | Energy to biodiversity: pollution from backup fuels (0.2); Biodiversity to energy: biomass (0.1)                                                                    | 0.15                          |
| Food and Health         | Relation in play | Food to health: nutrition (0.7); Health to food: farm labour (0.3)                                                                                                  | 0.50                          |
| Food and Biodiversity   | Relation in play | Food to biodiversity: land conversion (0.6); Biodiversity to food: pollination and soils (0.6)                                                                      | 0.60                          |
| Health and Biodiversity | Relation in play | Health to biodiversity: conservation capacity (0.1); Biodiversity to health: zoonotic spillover and medicines (0.4)                                                 | 0.25                          |
| Water                   | Sector           | first hit, then depends on energy for pumping and treatment                                                                                                         | stress 0.72                   |
| Energy                  | Sector           | depends on water for cooling water and hydropower                                                                                                                   | stress 0.19                   |
| Infrastructure          | Sector           | outside this context                                                                                                                                                | –                             |
| Food                    | Sector           | depends on water for irrigation                                                                                                                                     | stress 0.30                   |
| Health                  | Sector           | depends on water for drinking water and sanitation                                                                                                                  | stress 0.30                   |
| Biodiversity            | Sector           | depends on water for environmental flows                                                                                                                            | stress 0.23                   |
| Amplification           | Cascade          | Shock 0.6 at Water, gain 0.35, 4 rounds; coupling 0.68 of the total                                                                                                 | ×2.89                         |
| F01                     | Handoff in play  | Universe to Foundry: Admitted mission becomes a cycle project with a decision case                                                                                  | Readiness preparation         |
| F02                     | Handoff in play  | Foundry to Universe: Core Build Report and go or no-go evidence                                                                                                     | Controlled build              |
| F03                     | Handoff in play  | Foundry to Reports: Sealed observations and indicator series behind a profile                                                                                       | Closeout                      |
| F04                     | Handoff in play  | Universe to Reports: After-action and scenario findings for chapters 10 and 13                                                                                      | After-action review           |
| F05                     | Handoff in play  | Foundry to Reports: National Portfolio movement for chapter 11                                                                                                      | After-action review           |
| F06                     | Handoff in play  | Reports to Standards: Method and correction findings as change proposals                                                                                            | Correction                    |
| F07                     | Handoff in play  | Universe to Standards: Docket items that need a standard or a profile                                                                                               | Docket review                 |
| F08                     | Handoff in play  | Standards to Foundry: Composed mission profiles and national adoption records                                                                                       | Readiness preparation         |
| F09                     | Handoff in play  | Standards to Academy: Each adopted standard or profile becomes a course module                                                                                      | Renewal                       |
| F10                     | Handoff in play  | Universe to Academy: Assessed cycle tasks become completion evidence                                                                                                | Closeout                      |
| F11                     | Handoff in play  | Academy to Universe: Qualified participants for the next cycle's roles                                                                                              | Renewal                       |
| F12                     | Handoff in play  | Reports to Universe: Q4 synthesis informs the next-year mandate                                                                                                     | Renewal                       |
| F13                     | Handoff in play  | Foundry to Standards: Validation and monitoring evidence for conformance review                                                                                     | Controlled build              |
| F14                     | Handoff in play  | Foundry to Academy: Each system's rooms become a learning-by-doing course                                                                                           | Planning                      |
| R1                      | Handoff in play  | Standards to Reports: Applied in editions                                                                                                                           | Around the ring               |
| R2                      | Handoff in play  | Reports to Academy: Taught in the open                                                                                                                              | Around the ring               |
| R3                      | Handoff in play  | Academy to Labs: Questions become experiments                                                                                                                       | Around the ring               |
| R4                      | Handoff in play  | Labs to Foundry: Tested prototypes are built                                                                                                                        | Around the ring               |
| Labs                    | Pillar           | Drought index from rainfall, soil moisture and river flow                                                                                                           | Lead time to trigger ↑        |
| Foundry                 | Pillar           | Allocation model for irrigation, cooling and drinking water                                                                                                         | Demand met in drought ↑ $7.1T |
| Universe                | Pillar           | Early-action exercise with water and agriculture ministries                                                                                                         | Days from trigger to action ↓ |
| Standards               | Pillar           | Trigger thresholds and records agencies can share                                                                                                                   | Triggers adopted ↑            |
| Reports                 | Pillar           | Seasonal drought outlook and food-price signals                                                                                                                     | Outlooks issued ↑             |
| Academy                 | Pillar           | Course for basin and food-security officers                                                                                                                         | Officers qualified ↑          |
| Return on resilience    | Cited value      | From $1.8T invested in five adaptation areas from 2020 to 2030, water management among them. Global Commission on Adaptation, Adapt Now, 2019                       | $7.1T net benefits            |
| Planning                | Phase (Q1, G0)   | F14 Each system's rooms become a learning-by-doing course                                                                                                           | 1 handoff(s)                  |
| Readiness preparation   | Phase (Q2, G2)   | F01 Admitted mission becomes a cycle project with a decision case; F08 Composed mission profiles and national adoption records                                      | 2 handoff(s)                  |
| Controlled build        | Phase (Q2, G3)   | F02 Core Build Report and go or no-go evidence; F13 Validation and monitoring evidence for conformance review                                                       | 2 handoff(s)                  |
| Closeout                | Phase (Q3, G5)   | F03 Sealed observations and indicator series behind a profile; F10 Assessed cycle tasks become completion evidence                                                  | 2 handoff(s)                  |
| After-action review     | Phase (Q3)       | F04 After-action and scenario findings for chapters 10 and 13; F05 National Portfolio movement for chapter 11                                                       | 2 handoff(s)                  |
| Correction              | Phase (Q4)       | F06 Method and correction findings as change proposals                                                                                                              | 1 handoff(s)                  |
| Docket review           | Phase (Q4)       | F07 Docket items that need a standard or a profile                                                                                                                  | 1 handoff(s)                  |
| Renewal                 | Phase (Q4, G7)   | F09 Each adopted standard or profile becomes a course module; F11 Qualified participants for the next cycle's roles; F12 Q4 synthesis informs the next-year mandate | 3 handoff(s)                  |

</details>

## Coupled risk

| Sector                                                          | In this context                                             | Stress after four rounds |
| --------------------------------------------------------------- | ----------------------------------------------------------- | ------------------------ |
| [Water](/organization/model/sectors/water.md)                   | Hit first; then depends on energy for pumping and treatment | 0.72                     |
| [Energy](/organization/model/sectors/energy.md)                 | Depends on water for cooling water and hydropower           | 0.19                     |
| [Infrastructure](/organization/model/sectors/infrastructure.md) | Outside this context                                        | –                        |
| [Food](/organization/model/sectors/food.md)                     | Depends on water for irrigation                             | 0.30                     |
| [Health](/organization/model/sectors/health.md)                 | Depends on water for drinking water and sanitation          | 0.30                     |
| [Biodiversity](/organization/model/sectors/biodiversity.md)     | Depends on water for environmental flows                    | 0.23                     |

Amplification ×2.89; 10 of the 15 relations in play; coupling 0.68 of the total. Teaching values for a typical city-region, not measurements for any place. Coupling is the summed strength of the relations in play, as a share of all fifteen.

**What it means for a study.** Drought is the most tightly coupled of the eight contexts: five sectors and ten relations, and the highest amplification in the teaching set. Low river flows cut irrigation, cooling water and hydropower at once, and food prices, nutrition and ecosystems follow. A drought study that looks only at rainfall or only at agriculture misses the energy and health paths.

## Applied response

| Pillar                                                            | Illustrative application                                    | Measure it answers for      | Better when | Sectors served              |
| ----------------------------------------------------------------- | ----------------------------------------------------------- | --------------------------- | ----------- | --------------------------- |
| [Labs](/organization/programme/labs.md) (applied)                 | Drought index from rainfall, soil moisture and river flow   | Lead time to trigger        | higher      | Water, Food                 |
| [Foundry](/organization/programme/foundry.md) (applied)           | Allocation model for irrigation, cooling and drinking water | Demand met in drought       | higher      | Water, Energy, Food, Health |
| [Nexus Universe](/organization/programme/universe.md) (applied)   | Early-action exercise with water and agriculture ministries | Days from trigger to action | lower       | Water, Food                 |
| [Nexus Standards](/organization/programme/standards.md) (applied) | Trigger thresholds and records agencies can share           | Triggers adopted            | higher      | Water, Food                 |
| [Nexus Reports](/organization/programme/reports.md) (applied)     | Seasonal drought outlook and food-price signals             | Outlooks issued             | higher      | Food, Health                |
| [Risk Academy](/organization/programme/academy.md) (applied)      | Course for basin and food-security officers                 | Officers qualified          | higher      | Water, Food, Biodiversity   |

**What it means for a response.** Every pillar applies, and all eighteen handoffs are in play. The response is early action on agreed triggers: Labs builds a drought index from rainfall, soil moisture and river flow; the Foundry allocates water between irrigation, cooling and drinking water; Universe exercises the days from trigger to action with water and agriculture ministries; Standards records the trigger thresholds agencies share. In every case the responsible government, operator or licensed institution decides and acts; the programme informs that decision.

## Published benchmarks

| Slot                 | Value              | What it measures                                                                            | Source                                                                                                                                    |
| -------------------- | ------------------ | ------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| Value at risk        | –                  | No published benchmark for this context                                                     | –                                                                                                                                         |
| Return on resilience | $7.1T net benefits | From $1.8T invested in five adaptation areas from 2020 to 2030, water management among them | [Global Commission on Adaptation, Adapt Now, 2019](https://gca.org/reports/adapt-now-a-global-call-for-leadership-on-climate-resilience/) |
| Avoided loss         | –                  | No published benchmark for this context                                                     | –                                                                                                                                         |

Each value is international evidence with its own scope, cited on the same line. None is a forecast for any project or place. See [Method and limits](/organization/model/method-and-limits.md) for how to read the values precisely.

## On the public sites

The same context, with the same values, is shown on the [GCRI about](https://therisk.global/about/), the [GCRI life-support systems](https://therisk.global/challenges/life-support-systems/) and the [GRF home](https://globalriskforum.com/) pages.

## Related pages

[All scenarios](/organization/model/scenarios.md) · [Coupled risk](/organization/model/coupled-risk.md) · [Applied response](/organization/model/applied-response.md) · [Water](/organization/model/sectors/water.md) · [Energy](/organization/model/sectors/energy.md) · [Food](/organization/model/sectors/food.md) · [Health](/organization/model/sectors/health.md) · [Biodiversity](/organization/model/sectors/biodiversity.md)

## Sources

* Global Commission on Adaptation, Adapt Now, 2019. <https://gca.org/reports/adapt-now-a-global-call-for-leadership-on-climate-resilience/>
* The model data: the "Coupled risk, applied response" section of the [GCRI home page](https://therisk.global/).


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