Centre for Sustainable Development Reform · Scaffold reference reports · Analysis
A reference analysis of the NOAA Global Monitoring Laboratory record, 1958–2026 — the scaffold's demonstration report
Section 1
1 · Why this record
The Mauna Loa series is the longest continuous direct record of atmospheric CO₂, begun by Charles David Keeling in March 1958 (Keeling et al., 1976) and continued by NOAA since 1974 (Thoning et al., 1989); the current files are published by NOAA GML (Lan et al., 2026). It is the canonical example of a data product with clear provenance, a stable schema and a citation request from its publisher — exactly the kind of source a CSDR report should be able to consume without ceremony. The values on this page are read at build time from the noaa-mlo-co2 bundle described under Data, and every figure offers the data it was drawn from.
1 · Why this record
Rows are loaded from the bundle’s Parquet and CSV files by build-time loaders (data/loaders), derived quantities (annual means, decadal growth, the last five seasonal cycles) are computed in one memoised analysis cell, and each chart is rendered to SVG at build with a data table and CSV/SVG downloads. Nothing on this page is typed by hand — change the bundle, rebuild, and the text updates.
Section 2
Figure 1 shows the annual mean since 1959.
2 · The long-term trend · Figure 1
Source NOAA GML (Lan, Tans & Thoning, 2026); Scripps Institution of Oceanography for 1958–1974.
2 · The long-term trend
Figure 1 shows the annual mean since 1959. The curve is not a straight line: the increment added each year has grown from under one part per million in the early 1960s to two-to-three parts per million in most recent years (Figure 2). Decadal averages make the acceleration plain (Figure 3, Table 1).
2 · The long-term trend · Figure 2
Source NOAA GML.
2 · The long-term trend · Figure 3
Source NOAA GML; CSDR calculation.
2 · The long-term trend · Table 1
| Year | Annual mean (ppm) | Increase on previous year (ppm) |
|---|---|---|
| 2016 | 404.41 | 3.03 |
| 2017 | 406.76 | 1.90 |
| 2018 | 408.72 | 2.85 |
| 2019 | 411.65 | 2.49 |
| 2020 | 414.21 | 2.30 |
| 2021 | 416.41 | 2.35 |
| 2022 | 418.53 | 1.84 |
| 2023 | 421.08 | 3.32 |
| 2024 | 424.61 | 3.33 |
| 2025 | 427.35 | 2.23 |
Source NOAA GML.
Section 3
Within each year, CO₂ at Mauna Loa peaks in May and reaches its minimum in September or October (Figure 4), as Northern-Hemisphere plants draw down carbon through the growing season and release it in autumn and winter.
3 · The seasonal cycle · Figure 4
Source NOAA GML.
3 · The seasonal cycle
Within each year, CO₂ at Mauna Loa peaks in May and reaches its minimum in September or October (Figure 4), as Northern-Hemisphere plants draw down carbon through the growing season and release it in autumn and winter. The amplitude is a few parts per million — small against the trend, but a useful reminder that a single month’s reading is not a year’s mean, which is why the headline figures above quote both.
3 · The seasonal cycle
Measurements from Mauna Loa Observatory were suspended after the November 2022 eruption and resumed in July 2023; December 2022 – early July 2023 values come from Maunakea, about 21 miles north. Interpolated months in the NOAA files carry negative standard deviation and uncertainty flags, and are excluded from the monthly series used here.
Section 4
For SEEA (System of Environmental-Economic Accounting)-style work the point is not the number itself but its lineage.
4 · What this means for accounts
For SEEA (System of Environmental-Economic Accounting)-style work the point is not the number itself but its lineage. A carbon or ecosystem account that cites an atmospheric baseline needs to know which file, which version and which publisher’s citation applies (United Nations et al., 2021). The scaffold’s bundle contract carries that lineage next to the data, and the report’s citation block carries the report’s own. Physical-science context for the trend is given by the IPCC’s Sixth Assessment Report (IPCC, 2021).
References
Cite this report
CSDR Platform Team (2026). Atmospheric CO₂ at Mauna Loa: A reference analysis of the NOAA Global Monitoring Laboratory record, 1958–2026 — the scaffold's demonstration report (v1.0). Centre for Sustainable Development Reform. https://test.csdr.global/reports/atmospheric-co2-2026/
test.csdr.global/reports/atmospheric-co2-2026
© 2026 Centre for Sustainable Development Reform · CC BY 4.0 · Data: Atmospheric CO₂ at Mauna Loa Observatory (NOAA GML) · The report, its PDF and this deck are built from the same source.
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