# Annual carbon dioxide and temperature data

`climate-annual.csv` contains 65 matched annual observations, 1959–2023.
These are observed estimates published by NOAA, not simulated data.
The snapshots were retrieved on 2026-10-20 and are retained in `original/`.

| Column | Meaning and units |
|---|---|
| `year` | Calendar year. |
| `co2_ppm` | Annual mean atmospheric carbon dioxide mole fraction in dry air, in parts per million (micromoles per mole), from NOAA's Mauna Loa record. |
| `temperature_global_c` | Annual global land-and-ocean surface temperature anomaly, degrees Celsius relative to the 1901–2000 average. |
| `temperature_land_c` | Annual global land surface temperature anomaly, degrees Celsius relative to the 1901–2000 average. |
| `temperature_ocean_c` | Annual global ocean surface temperature anomaly, degrees Celsius relative to the 1901–2000 average. |

An anomaly subtracts a reference-period mean; it does not remove a time trend.
The temperature columns use the same reference period. Carbon dioxide
concentration is a stock measure, not annual carbon emissions.

## Sources

- NOAA Global Monitoring Laboratory, [Trends in Atmospheric Carbon Dioxide](https://gml.noaa.gov/ccgg/trends/data.html).
  [Annual Mauna Loa text file](https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_annmean_mlo.txt),
  snapshot `original/co2_annmean_mlo.txt`, file creation date 2026-10-09.
  Credit: Xin Lan, NOAA/GML, and Ralph Keeling, Scripps Institution of Oceanography.
- NOAA National Centers for Environmental Information,
  [Climate at a Glance: Global Time Series](https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series).
  The following queries use the complete January–December year (`ytd/12`):
  [global land and ocean](https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/globe/land_ocean/ytd/12/1850-2023.csv),
  [global land](https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/globe/land/ytd/12/1850-2023.csv), and
  [global ocean](https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/globe/ocean/ytd/12/1850-2023.csv).
  Each retained CSV states degrees Celsius and the 1901–2000 base period.

The CO2 source notes that Mauna Loa measurements were suspended after the
November 2022 eruption. Observations from December 2022 through July 4, 2023
come from Maunakea Observatories. We retain the annual series as published.
The source also credits Scripps for observations before May 1974.

## Preparation

Preparation: select the CO2 `mean` column; read the three temperature CSVs;
join by calendar year; retain 1959–2023. No values are imputed, interpolated,
rescaled, or rounded beyond the precision of the source files.

There are no missing years or missing values. First and second differences
are dated by their ending year, starting in 1960 and 1961 respectively.
The workbook plots use blue for CO2 and brown for temperature. In the
detrending comparisons, a dashed grey line shows the fitted linear trend
and a dotted black line shows the fitted quadratic trend.