Leading the health V&A evidence for the NAP

Our expert team at Principal Economics leads the Ministry of Health’s climate–health Vulnerability and Adaptation (V&A) assessment. The assessment is a key driver of adaptation strategy because it turns climate change into quantified, place-based health risks and clarifies which interventions reduce harm. It aligns directly with the health sector’s adaptation direction set out in the Ministry’s Health National Adaptation Plan (HNAP), and it supports the wider National Adaptation Plan (NAP) led by the Ministry for the Environment. See: Health National Adaptation Plan 2024–2027 and National Adaptation Plan.

We use a decision-grade evidence chain. We start with explicit climate scenarios because scenarios define the risk envelope, timing, and the appropriate adaptation stance. From scenarios, we map hazard pathways with measurable indicators. We then link those hazard indicators to granular health risks across communities using condition-specific relative risk matrices. Finally, we focus on health system capacity as the core instrument for reducing vulnerability—assessed through a social welfare lens that makes economic constraints and equity trade-offs explicit.

Scenarios anchor adaptation choices

Climate scenarios are not a technical preface. They determine what government is planning for, when impacts emerge, and whether the right response is incremental adjustment or structural change. Without explicit scenario choices, strategy tends to drift toward median planning (systematically under-preparing) or toward unbounded risk aversion (over-investing without transparency).

Our V&A work therefore starts with scenario selection and uses it to structure the evidence base. Scenarios define the plausible future conditions that drive hazard frequency, intensity, and duration. This creates a disciplined basis for prioritisation and sequencing: scenario choices set the envelope for action, and subsequent modelling clarifies which investments remain robust across plausible futures.

Pathways connect climate to health

From scenarios, we map the climate–health pathways that matter for New Zealand. These include extreme weather injuries and fatalities; heat-related illness and mortality; waterborne and foodborne diseases; vector-borne diseases; respiratory impacts from air quality, wildfire smoke, and allergens; and mental health and wellbeing. Each pathway specifies (i) the climate driver, (ii) the hazard manifestation relevant to New Zealand, and (iii) the indicator set used to represent it in a measurable and updateable way.

This pathway structure avoids an unprioritised hazard list. It produces a portfolio that can be compared, stress-tested, and revised as evidence improves. It also makes policy levers clearer by linking hazards to operationally meaningful metrics that can inform warnings, preparedness planning, and service design.

Indicators designed for implementation

Hazard indicators form the interface between climate science, modelling, and policy. We prioritise indicator sets that agencies can observe historically, project under scenarios, and interpret in operational settings. Where feasible, we align indicators with the way risks are managed in practice—through thresholds, alerts, standards, and planning assumptions—so the assessment connects directly to intervention design.

This matters for the NAP because monitoring and accountability depend on measurable constructs. An implementable indicator set allows agencies to (i) define triggers, (ii) target interventions, and (iii) track whether adaptation reduces vulnerability over time. It also improves transparency by making clear how hazard change is represented and how results would shift under alternative indicator choices.

Relative risk matrices translate evidence

The technical translation step uses condition-specific relative risk matrices: structured mappings from exposure (and where relevant, lagged exposures) to changes in health risk. These matrices provide the bridge from scenario-driven shifts in hazards to quantified impacts on morbidity and mortality. They also support comparability across hazards and health conditions by putting results on a common risk footing that can be aggregated, decomposed, and communicated clearly.

We keep the purpose strategic. Relative risk matrices allow decision-makers to see where marginal risk reduction is likely to be greatest and where targeted investment will deliver the strongest welfare gains. They also preserve auditability by linking priorities back to the underlying evidence and key assumptions.

Granular community risk, not averages

Adaptation decisions must work where risks manifest and services respond. National averages conceal clustered vulnerability, compounding disadvantage, and local capacity constraints. We therefore apply the scenario–hazard–risk chain at fine spatial resolution to identify priority communities and suburbs, rather than only reporting broad regional patterns.

This granularity supports equity-centred planning. It shows how the same hazard can lead to different impacts depending on baseline health, exposure patterns, socioeconomic conditions, and adaptive capacity. It also improves validation and learning because local results can be compared with observed service use and outcomes, strengthening confidence in priorities and highlighting where further evidence development is needed.

Health system capacity is the core lever

We place health system capacity at the forefront because it is the primary instrument that turns climate risk into avoidable harm—or preventable resilience. Exposure may rise under most scenarios, but outcomes depend on prevention, access, quality of care, surge capability, continuity planning, and public health functions. Capacity therefore operates across hazards and supports actions that remain valuable under multiple futures.

This framing shifts V&A from describing vulnerability to reducing it. It supports practical adaptation packages such as strengthening primary and preventive care, improving emergency readiness, enhancing surveillance and early warning, protecting continuity of care during extreme events, and targeting underserved areas where welfare gains are largest. This focus is consistent with the intent of the Ministry’s HNAP to strengthen health-sector readiness and resilience.

Social welfare and economic realism

Capacity decisions require a social welfare lens because adaptation involves real trade-offs under resource constraints. A welfare framing makes objectives explicit: reduce avoidable morbidity and mortality, protect equity, and maintain system functioning. It also provides a principled basis to compare interventions that operate through different channels—prevention, service delivery, infrastructure, and community supports.

Concluding remarks

New Zealand’s adaptation strategy needs a clear line of sight from climate futures to health outcomes and to the capacity investments that reduce harm. Our V&A work provides that line of sight by combining scenario-led hazard analysis, evidence-based relative risk translation, granular community impacts, and an explicit focus on health system capacity under a social welfare and economic lens. This approach strengthens prioritisation, supports equity, and improves the implementability and accountability of the NAP.

Links: Ministry of Health HNAP · National Adaptation Plan · HVAT Toolkit