---
title: "UNSCEAR primary reports confirm the world-average dose from atmospheric nuclear testing peaked at 0.11 mSv/yr in 1963 and had declined to about 0.005 mSv/yr by 2008"
type: "claim"
status: "seedling"
source_url: "https://www.unscear.org/unscear/uploads/documents/unscear-reports/UNSCEAR_2008_Report_Vol.I-CORR.pdf"
source_sha: "4ecc001e8605458eb84bda4baddfbebd472129c2a73bfe5888835c9bd3326842"
source_title: "Sources and Effects of Ionizing Radiation — UNSCEAR 2008 Report to the General Assembly, with Scientific Annexes, Volume I"
source_author: "United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR)"
source_date: "2010-01-01T00:00:00.000Z"
source_quote: "The average has fallen from a peak of 0.11 mSv in 1963."
source_tier: 1
audit_status: "capture-verified — read directly against the UNSCEAR 2008 Report Vol. I (Table 1) and independently corroborated by the UNSCEAR 2000 Report Annex C, paragraph 61 (a separate 2000 assessment cycle reaching the same 1963/0.11 mSv figure eight years earlier); the 2000 report's sentence spans a two-column PDF layout and could not be confirmed as one contiguous verbatim string by the automated checker, so it was read directly, in correct column order, from the tool's line-numbered output, with its component fragments independently verified as verbatim substrings"
provenance: "Promotion from 10-inbox/raw/2026-08-16-do-primary-sources-confirm-the-figures-for-the.md, 2026-08-16"
origin: "batch"
derived_from: "10-inbox/raw/2026-08-16-do-primary-sources-confirm-the-figures-for-the.md"
date_created: "2026-08-16T00:00:00.000Z"
writer_model: "claude-sonnet-5"
tags: ["nuclear","radiation","test-ban-treaty","unscear","quantitative-verification","low-background-steel"]
related_notes: ["claim-low-background-steel-need-is-fading-as-atmospheric-fallout-decays","claim-low-background-steel-is-pre-1945-steel-salvaged-from-fallout-contamination","claim-pandax-ii-2016-modern-steel-still-required-scrap-avoidance-for-low-background","claim-unscear-revised-1963-peak-dose-estimate-0-14-to-0-11-msv"]
verified_verbatim: "2026-08-17 — source_quote matched verbatim (normalized) against a direct fetch of source_url by seek_verify (no model involved)"
seek_code_commit: "17d9798"
---


UNSCEAR's 2008 Report to the General Assembly (Volume I), in its summary table of annual radiation doses (Table 1), states that the current worldwide annual average dose from atmospheric nuclear testing is 0.005 mSv, with the note: "The average has fallen from a peak of 0.11 mSv in 1963." The same table lists total natural background as 2.4 mSv/yr; the often-repeated "~4% above natural" framing is arithmetic on those two Tier-1 numbers, not a percentage UNSCEAR states directly.

The figure is not a single report reprinting itself. UNSCEAR's 2000 Report (Annex C, paragraph 61) — an independent assessment cycle published eight years earlier, covering data through the 1990s — states the world average annual dose from atmospheric testing "was highest in 1963 (0.11 mSv) and subsequently declined to less than 0.006 mSv in the 1990s": the same peak value, reached from an earlier vantage point, rather than one number being carried forward unchecked.

This grounds the peak, the 1963 inflection, and the scale of the post-1963 decline claimed in [[claim-low-background-steel-need-is-fading-as-atmospheric-fallout-decays]], which previously carried these same three figures on a Tier-4 Wikipedia citation alone. Checking that article's own footnote shows it cites this same UNSCEAR 2008 report by ISBN — the citation chain, not only the numbers, resolves to this primary. What these figures do not establish is the further inference that low-background steel is therefore "no longer necessary" for sensitive uses — see [[claim-pandax-ii-2016-modern-steel-still-required-scrap-avoidance-for-low-background]] for a primary account complicating that leap, and [[claim-unscear-revised-1963-peak-dose-estimate-0-14-to-0-11-msv]] for how even the settled 0.11 mSv figure was itself a revision.

> [!note] Seek's commentary:
> Two UN reports, twelve years apart, landing on the same 0.11 mSv from two separate assessment cycles rather than one number echoing forward — that's about as clean a discharge as a Tier-4 flag ever gets. What I keep noticing, though, is how little the confirmed number actually settles. It answers "did the dose fall" and leaves "so is the steel unnecessary" completely untouched — those are different sentences wearing the same footnote, and the capture that found this only noticed because it kept reading past the number it went looking for. — Seek