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Cyclone and marine-heatwave season across the Coral Sea and nearby island coasts

A conditional statement under stated assumptions, never a prediction.

2 min read0 figures0 tables2 notesNR-REGIONAL-OCP-2026-BASELINE

Contents
  1. ·Edition home
  2. ·Executive summary
  3. 1Oceania-Pacific’s risk is set by ocean, coast and distance
  4. 2Key findings
  5. 3Systems and sectors at baseline
  6. 4Risks and capability
  7. 5Cyclone and marine-heatwave season across the Coral Sea and nearby island coasts
    1. 5.1 Assumptions
    2. 5.2 The cascade, step by step
    3. 5.3 The scenario as a table of steps
  8. 6Readings from the other desks
  9. 7The 2027 agenda
  10. 8Systems in depth
  11. AMethodology
  12. BData appendix
  13. CReferences and record
  14. ·Complete edition, for print

5.1Assumptions

Scenario SCN-OCP-CYC-01: what is assumed, and what is held constant.

Baseline
the 2026 reference state in this edition
Drivers
a warm-ocean season with a severe cyclone, storm surge and a marine heatwave, followed by heat on land
Analogues
2024 marine heatwaves and warmest year in the South-West Pacific18; electricity access gaps14
Interventions
none modelled, the specification describes the unmitigated case
Run state
narrative specification; quantified Foundry run scheduled for Q1 2027

5.2The cascade, step by step

  1. 1

    CLI → INF

    cyclone and surge damage coastal roads, ports and power lines

    coastal exposure18

  2. 2

    INF → ENE

    power and fuel supply fail where access is already thin

    access 20.5% in Papua New Guinea14

  3. 3

    CLI → WAT

    salt intrusion and damaged supplies cut drinking water

    no analogue bound

  4. 4

    ENE → HLT

    clinics and cold chains lose power while heat follows

    no analogue bound

  5. 5

    HLT → FIN

    losses fall on households, insurers and budgets

    loss series not bound

  6. 6

    FIN → recovery

    rebuilding slows where cover is thin

    loss series not bound

5.3The scenario as a table of steps

How the shock in scenario SCN-OCP-CYC-01 would travel through Oceania-Pacific’s coupled systems, step by step, under the assumptions the edition states.

StepWhat happensSource
01 Climate to infrastructureCyclone and surge damage coastal roads, ports and power lines. Analogue or source: coastal exposure [18].Edition REG-OCP, scenario SCN-OCP-CYC-01, step 1
02 Infrastructure to energyPower and fuel supply fail where access is already thin. Analogue or source: access 20.5% in Papua New Guinea [14].Edition REG-OCP, scenario SCN-OCP-CYC-01, step 2
03 Climate to waterSalt intrusion and damaged supplies cut drinking water. Analogue or source: no analogue bound.Edition REG-OCP, scenario SCN-OCP-CYC-01, step 3
04 Energy to healthClinics and cold chains lose power while heat follows. Analogue or source: no analogue bound.Edition REG-OCP, scenario SCN-OCP-CYC-01, step 4
05 Health to financeLosses fall on households, insurers and budgets. Analogue or source: loss series not bound.Edition REG-OCP, scenario SCN-OCP-CYC-01, step 5
06 Finance to recoveryRebuilding slows where cover is thin. Analogue or source: loss series not bound.Edition REG-OCP, scenario SCN-OCP-CYC-01, step 6

A teaching model of a conditional scenario under the edition’s stated assumptions: not a forecast, not a prediction and not a warning. Sources: Oceania-Pacific 2026, scenario SCN-OCP-CYC-01 (2026); Oceania-Pacific 2026, references (NR-CIT-1) (2026).

Notes

Numbers are the edition’s reference numbers, so a note reads the same in every chapter. The full list, with every source and its licence, is in Annex C. Annex C, references

  1. 18World Meteorological Organization (ed.), Ocean heat and sea-level rise threaten communities in the South-West Pacific (news release on the 2024 report; 0.48 °C above 1991–2020, about 40 million km² of marine heatwaves, more than half of Pacific islanders within 500 m of the coast, at least 50,000 islanders a year at displacement risk). WMO, Geneva, June 2025. Observation year 2024. Accessed 2026-11-03.back
  2. 14World Bank (ed.), World Development Indicators: access to electricity (EG.ELC.ACCS.ZS, 2023) and people using safely managed drinking water services (SH.H2O.SMDW.ZS, 2022; value returned for Fiji only), Australia, Fiji, Papua New Guinea and Pacific island small states. World Bank, Washington DC. Observation year 2023. Accessed 2026-11-03.back

Cite this chapter

Valadbaygi, S. (Ed.). (2026). Chapter 5: Cyclone and marine-heatwave season across the Coral Sea and nearby island coasts. In Oceania-Pacific Regional Systems Risk and Resilience Report 2026: Baseline Edition, The State of Oceania-Pacific’s Interdependent Systems. (Baseline Edition 2026, Report No. NR-REGIONAL-OCP-2026-BASELINE) [Draft under review]. The Global Centre for Risk and Innovation (GCRI).

Every citation form of the whole report, BibTeX and RIS included, is on the edition home. Cite this report

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Sector signature

The sectors behind Oceania-Pacific.

A reading aid: the sectors the findings run through and how strongly they depend on each other.

Select corners · hover lines10 / 15 relations

Context

Coastal storm surge

Mangroves and dunes absorb the surge; where they are gone, ports, substations and water intakes take it.

W · E · I · F · H · B

Sectors
5 of 6
Relations
10 of 15
Coupling
0.64 share of total

Strongest relations in play

  • Energy → Infrastructure · power for transport and telecoms0.8
  • Water → Energy · cooling water and hydropower0.6
  • Water → Biodiversity · environmental flows0.6
  • Infrastructure → Water · pipes, dams and treatment works0.6
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.
The Global Centre for Risk and Innovation

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