Credibility armor · model 0.1.0-phase1

How we count.

Every number on this site is an estimate, produced by an openly published model from public data. Nothing here is a counted body. This page exists so you can check our work, and tell us where we're wrong.

The model · part 1

Estimating heat deaths

Per country, per day (Brief §5.1):

1. Pull the daily mean temperature from Open-Meteo (free, no key), cached ~1h.
2. Compare it to a region-specific Minimum Mortality Temperature (MMT) - the temperature at which mortality is lowest. We use daily-mean MMTs from the MCC / Gasparrini literature: France 18°C, Germany 19°C, UK 19°C, Spain 21°C, Italy 23°C.
3. Apply a heat exposure-response function that rises above the MMT and accelerates at the extremes:

   RR(T) = 1 + β₁·ΔT + β₂·ΔT², where ΔT = max(0, T − MMT)
   β₁ = 0.006 per °C · β₂ = 0.001 per °C² (the tail)

4. excess_deaths/day = (annual_deaths / 365) × (RR − 1) × calibration
5. Sum across countries and days into the running counter.

Shape, anchored to literature: these β values give RR ≈ 1.05 a few °C above the MMT, climbing toward ~1.2 at the extreme tail, consistent with the MCC network / Gasparrini et al. curves. Each country then gets a calibration factor so the model, run over that country's real 2024 summer temperatures (Open-Meteo archive), reproduces its published 2024 total exactly (IT 2.25, ES 0.80, FR 0.80, DE 1.07, GB 2.24). The factor absorbs the single-capital approximation.

By year. 2024 is the published ISGlobal total (62,775). 2025 and 2026 are our calibrated model run over Open-Meteo's archived summers, per country, then summed (8 countries, extrapolated to Europe: ~64,000 for 2025, ~61,000 projected for 2026). The 2026 ranking projects each country's full summer from this year's temperatures so far plus the rest of the season at 2025's climate. The UK sits outside the comparable ISGlobal dataset, so it is flagged and not ranked.

The model · part 2

Estimating economic loss

Per country, per day (Brief §5.2):

1. For days where the daily mean temperature exceeds 30°C:

   productivity_loss% = 3% × (T − 30)
   ≈ 3% of mean hourly output lost per °C across 30-35°C (Allianz Trade, Too hot to grow, 2026)

2. daily_GDP = annual_GDP / 365
3. lost_output = daily_GDP × labour_share × productivity_loss%
4. Sum into the running € counter.

The EU annual anchor (€50-80B, 0.3-0.5% of GDP) comes from García-León et al. 2021 (Nature Communications), relayed by the European Parliament EPRS (2025). The per-country GDP-loss rankings on /economics are Allianz Trade's 2026-2030 cumulative projections (USD).

The model · part 3

How the live counters tick

Two rate sources, and we are explicit about both:

• Baseline rate (published-anchored). The big "this summer" counters tick from June 1 at a constant rate derived from the published totals, ISGlobal's 62,775 European heat deaths (summer 2024) and the €50-80B/yr (midpoint €65B) productivity loss, spread across a 92-day summer. This is why the headline numbers always reconcile to published figures rather than to a single hot day.
• Live rate (model-driven). The "since you opened this tab" ticker runs the model above against today's Open-Meteo temperatures and shows max(baseline, live), reliable on a mild day, and it spikes during a heatwave. The per-second drip is the aggregate daily rate divided by 86,400.

Resulting baseline drip, Europe-wide: 0.0079 estimated deaths/sec and €8,177/sec.

Phase 1 coverage: live temperatures currently come from the capital of each of the 5 priority countries (a single point, not 654 regions). The 5 countries account for 48,528 of 62,775 published 2024 deaths, so the Europe-wide live aggregate is scaled up by a factor of ×1.29. Expanding to all 32 ISGlobal countries and to population-weighted regional temperatures is Phase 2.

Keeping ourselves honest

Sanity checks

• Deaths: the baseline counter is defined to sum to ISGlobal's 62,775 across a summer; the model's own exposure-response output is then calibrated toward the same per-country target (the calibration knob).
• Economics: the baseline annual run is anchored to the €50-80B EU range. At 3%/°C, a heatwave's GDP hit lands near Allianz's "half a day of strikes for every day above 32°C."

Everything, in one place

Per-country config

The exact values powering the site. Cells marked * carry a flag (see top).

* carries a flag explained at the top of this page.

Receipts

Sources

Found a number you think is wrong? That's the point, the openly-modeled framing is what lets critics improve this instead of dismissing it.