HemeraScope · EventsDemo
Pawston Cat Foods Ltd · 2026-03-19

Pawston Annual 2026

In-person, single-day · The Conservatory, Royal Horticultural Halls, London, UK · methodology event-v1.2.0

Total footprint
47.3 tCO₂e
95% CI 42.4–52.2 (±4.9)
Per attendee
103 kgCO₂e
±10.8 (95% CI)
Attendees
460
312 of 450 surveyed
Survey response rate
69.3%
Non-responders extrapolated
Headline with 95% confidence interval
5,000-iteration correlated Monte Carlo
42.447.3 tCO₂e52.2

The band reflects structural uncertainty in the emission factors and the extrapolation for non-responding attendees. Bit-identical replay from the same inputs hash — see Reproducibility.

Open the methodology atlas

The 47.3 tCO₂e headline decomposes across 7 GHG-Protocol scope categories and 26 emission lines. Every line names its DEFRA factor, version, vintage, and the carbon accountant who approved it.

  • · σ-banded on every line, not just the total
  • · DEFRA + CIBSE factors with version + vintage in plain text
  • · Override approver named with ISEP credential
  • · Double-count guard results explicit on every check
  • · Replay command on every published figure
Open the methodology atlas →

Scope split

Scope 3 (categories 1, 5, 6)44.1 tCO₂e · 93.3%
Scope 2 (venue energy, allocated)3.2 tCO₂e · 6.7%

Per ISO 20121 boundary practice, venue energy is allocated to the event by booked-hours share rather than scoped to the venue. GHG Protocol Scope 1 (mobile combustion) is nil — Pawston does not operate the venue.

Categories

Scope 3 · Cat 6 — Attendee travel41.2 tCO₂e
Scope 2 (location-based) — Venue energy (allocated)3.2 tCO₂e
Scope 3 · Cat 1 — Catering1.8 tCO₂e
Scope 3 · Cat 6 — Accommodation0.7 tCO₂e
Scope 3 · Cat 1 + 5 — Materials, signage & waste0.4 tCO₂e

Travel mode mix (top contributors)

ModePax sharePaxkgCO₂e
Short-haul flight14.8%6816,900
Car (petrol/diesel)22.5%1039,840
Rail38.0%1757,120
Long-haul flight4.2%196,010

Short-haul flights are 14.8% of attendees but the largest single contributor — the lever sits in catchment + invitation policy, not the day-of programme.

How we did this — three steps

Step 1
Survey

Public attendee-travel survey collects mode, origin postcode, and accommodation. Unique slug per event, rate-limited.

Survey results →
Step 2
Calculator

DEFRA-pinned factors run through the activity ledger; the structural σ engine bands every record. Non-respondents extrapolated by banded mode-mix.

Methodology →
Step 3
Publication

Snapshot frozen with an inputs hash. Re-runs replay bit-identical. Rolls up into the parent's Scope 3 Cat 6 for the reporting year.

Allocation →
Action over accounting.

The footprint is the easy part. The work that moves the number is invitation policy, catchment design, and venue choice — decisions made before the event, not after.

What this demo claims

  • · Every line names its DEFRA factor + version + vintage
  • · Every number σ-banded (central + 95% CI)
  • · Every line named to an ISEP-credentialed approver
  • · Inputs hash + MC seed published with headline; bit-identical replay
  • · Non-responder treatment documented inline with the σ it adds
  • · Double-count guard runs across every line — three checks each
  • · Methodology PDF mirrors the on-screen content from the same snapshot

What it doesn’t claim

  • · No verified third-party assurance — assuror signs; Hemera ships the pack
  • · No sector-specific add-on protocols wired in v1
  • · Factor lineage limited to DEFRA + CIBSE in v1; ecoinvent on roadmap
  • · Demo numbers are illustrative for a fictional event, not a real footprint
Sample event is illustrative. Numbers and attendees are fictional. The methodology, σ engine, factor lineage and publication snapshot are the same ones HemeraScope ships in production.
Last synced with the production methodology (event-v1) on 2026-06-10.