NOAA GML Mauna Loa (direct)
Window: 1958 CE-present | Tier: Direct instrumental
Direct atmospheric CO2 measurements from Mauna Loa.
This is a script-free static export intended for machine analysis by other AI systems.
Snapshot date: 2026-05-16 | Source page: co2_sources_guide.html
| Row | Data Type | Coverage Window | Notes |
|---|---|---|---|
| Direct atmospheric (NOAA GML) | Direct instrumental measurement | 1958 CE to current year | Mauna Loa monthly atmospheric CO2 |
| Law Dome ice-core (NOAA NCEI) | Trapped air bubbles, quasi-direct | 1 CE to 2006 CE (about 1,949 BP to modern) | Late Holocene to recent centuries |
| Antarctic composite ice-core (NOAA NCEI) | Trapped air bubbles, quasi-direct | 803,718 BCE to 2001 CE | Long Quaternary context |
| Vetted CenCO2PIP source window | Vetted proxy synthesis | About 66 million years ago to near-present | Cenozoic synthesis window |
| Archive extension source window | Original published proxy estimates, mixed methods | About 540 to 66 million years ago | Phanerozoic extension beyond vetted synthesis |
| Proxy method: phytoplankton | Proxy method listing | Shown as source-level availability scope | From current proxy_type metadata list |
| Proxy method: boron | Proxy method listing | Shown as source-level availability scope | From current proxy_type metadata list |
| Proxy method: stomata | Proxy method listing | Shown as source-level availability scope | From current proxy_type metadata list |
| Proxy method: leaf gas exchange | Proxy method listing | Shown as source-level availability scope | From current proxy_type metadata list |
| Proxy method: liverworts | Proxy method listing | Shown as source-level availability scope | From current proxy_type metadata list |
| Proxy method: land plant d13C | Proxy method listing | Shown as source-level availability scope | From current proxy_type metadata list |
| Proxy method: palaeosols | Proxy method listing | Shown as source-level availability scope | From current proxy_type metadata list |
| Proxy method: nahcolite | Proxy method listing | Shown as source-level availability scope | From current proxy_type metadata list |
Important: per-method rows are currently metadata-derived (not row-level parsed subsets) in the current unified CSV schema.
Window: 1958 CE-present | Tier: Direct instrumental
Direct atmospheric CO2 measurements from Mauna Loa.
Window: ~2 kyr BP to recent centuries | Tier: Ice-core trapped air
High-resolution Antarctic ice-core bubbles for late Holocene and pre-industrial CO2.
Window: 0-800 kyr BP | Tier: Ice-core trapped air
Merged Antarctic ice-core CO2 composite used for long Quaternary context.
Window: 0-66 Ma | Tier: Vetted proxy synthesis
Vetted Cenozoic proxy synthesis from paleo-co2.org and consortium releases.
Window: 0-540 Ma | Tier: Archive proxy extension
Original published proxy estimates for full Phanerozoic, before full CO2PIP re-processing. Values as published; uncertainty conventions are not harmonised across studies.
Window: 1958 CE–present | Tier: Direct instrumental
Independent direct atmospheric CO2 record maintained by Scripps Institution of Oceanography, parallel to and predating NOAA GML. Useful cross-check against Mauna Loa.
Window: 0–800 kyr BP | Tier: Ice-core trapped air
The standard 800-kyr composite for current research, combining EPICA Dome C, Vostok, TALDICE, EDML, and Talos Dome. Supersedes older single-core records for Quaternary context.
Window: 66 Ma–present (extending) | Tier: Vetted proxy synthesis
Live-updated Cenozoic compilation maintained by Foster, Rae, and collaborators. Web interface allows filtering by method, time range, and quality tier. Complementary to the static CenCO2PIP product.
Window: 1950s–present | Tier: Independent cross-validation
>30 million shipboard and autonomous pCO2 measurements across all ocean basins. Ocean surface pCO2 tracks atmospheric CO2 rise as expected from Henry's Law equilibrium — independent corroboration in a different medium.
socat.info | Bakker et al. 2016 (ESSD)
Use one tier per time window; do not overlay tiers within the same window unless explicitly visualising methodological agreement.
| Time range | Primary source |
|---|---|
| 1958 CE – present | NOAA GML Mauna Loa (or Scripps as cross-check) |
| ~1850 CE – 1958 CE | Law Dome (DE08/DE08-2) bridging into instrumental |
| ~2 kyr BP – present | Law Dome composite |
| ~800 kyr BP – present | Bereiter et al. 2015 Antarctic composite |
| 66 Ma – 800 kyr BP | CenCO2PIP (Hönisch et al. 2023) |
| Pre-66 Ma | CO2PIP Archive — label explicitly as exploratory |
Three independent physical signals corroborate the Mauna Loa CO2 trend and confirm the fossil-fuel origin of the rise.
| Signal | What is measured | Significance | Source |
|---|---|---|---|
| δ¹³C Suess effect | ¹³C/¹²C ratio of atmospheric CO2, declining since 1950s. Recorded in ice cores, tree rings, corals, and direct measurement. | Fossil fuel carbon is depleted in ¹³C. Isotopic decline rules out volcanic or biospheric sources as primary drivers. | NOAA GML stable isotopes; Scripps ¹³C record; Francey et al. 1999 |
| Atmospheric O₂/N₂ decline | O₂/N₂ ratio directly measured since 1989. Declining at ~1.4 O₂ consumed per CO2 released (varies by fuel type). | Closes the combustion mass balance. Oceanic degassing would not consume atmospheric O₂ — rules out ocean outgassing as primary source. | scrippso2.ucsd.edu (Ralph Keeling, SIO) |
| Ocean surface pCO₂ rise | Shipboard and autonomous pCO2 across all ocean basins (SOCAT, >30 M measurements). | Ocean surface pCO2 tracks atmospheric CO2 rise consistent with Henry's Law equilibrium. Independent dataset in a different medium. | SOCAT — socat.info |
Resolution differences of three to six orders of magnitude exist between modern instrumental data and deep-time proxies. Visual comparisons across these scales require explicit acknowledgement.
| Dataset | Typical resolution |
|---|---|
| Instrumental (Mauna Loa, Scripps) | Hours to months |
| Law Dome (DE08/DE08-2) | ~10–40 years |
| WAIS Divide | ~10–20 yr (Holocene); ~20–200 yr (glacial) |
| EPICA Dome C / Vostok | ~200–2,000 years |
| Cenozoic vetted proxies (CenCO2PIP) | ~10–100 kyr (interval-dependent) |
| Pre-Cenozoic archive proxies | ~Myr (highly variable) |
Age conventions used across datasets: CE/BCE = calendar year; yr BP = years before 1950 CE (by convention, not before current year); kyr BP = thousands of years before 1950 CE; Ma = millions of years before present. When stitching ice-core (yr BP) data to instrumental (CE) data, account for the 1950 reference offset.
Gas age vs ice age (Δage): Trapped gas bubbles are younger than the surrounding ice. Bubbles seal off at the base of the firn layer (~50–120 m depth). Δage varies by site: Law Dome ≈ 30–60 yr; WAIS Divide ≈ 200–500 yr; EPICA Dome C ≈ 2,000–7,000 yr. Matters when aligning CO2 records with temperature proxies at glacial terminations.