This repository contains the code and data needed to reproduce Figure 1 from *Kaufman, Darrell S. and McKay, Nicholas P, 2022, Technical Note: Past and future warming – Direct comparison on multi-century timescales. Climate of the Past.*. The article is open and available here.

Code

The code to reproduce this figure is written in R, and available in figure1.R. Several packages are required to run the code, and will need to be installed for the code to run.

Data

The time series data in figure 1 are included in data/TemperatureData.xlsx. The data are available from publicaly accessible sources, and have been modified relative to the 1850-1900 baseline as follows:

Hansen et al. (2013)

Data set: Late Quaternary global temperature according to equations by Hansen et al. (2013) applied to benthic marine oxygen isotope stack of Zachos et al. (2008).

Available: http://www.columbia.edu/~mhs119/Sensitivity+SL+CO2/Table.txt (last access: 21 March 2022).

Modified: Subtracted 14.15° C to adjust temperature relative to 1961-1990 and added 0.36°C to adjust to 1850-1900 reference period, based on the AR6 assessed four data set mean (Trewin, 2022; GMST-componentdatasets.csv).

Snyder (2016)

Data set: Late Quaternary multi-proxy sea surface temperature stack converted to global temperature by Snyder (2016).

Available: https://static-content.springer.com/esm/art%3A10.1038%2Fnature19798/MediaObjects/415862016BFnature19798MOESM258ESM.xlsx (last access: 21 March 2022).

Modified: Added 0.23° C to adjust late Holocene temperature to the 1850-1900 reference period, based on the reconstruction of Kaufman et al. (2020a).

Kaufman et al. (2020)

Data set: Holocene multi-method ensemble global temperature of Kaufman et al. (2020b), based on multi-proxy marine and terrestrial paleotemperature data (Temp12k; Kaufman et al., 2020a), using code of Routson et al. (2020).

Available: https://www.ncei.noaa.gov/access/paleo-search/study/29712 (Kaufman et al., 2020c; temp12kallmethodspercentiles).

Modified: Subtracted 0.03° C to adjust 19th century mean temperature to 1850-1900 reference period based on PAGES 2k Consortium (2019) 10-year smoothed multi-method reconstruction (Gilbert et al., 2021; SPM1_1-2000.csv).

Osman et al. (2021)

Data set: Last Glacial Maximum reanalysis (LGMR) of Osman et al. (2021a) based on marine paleotemperature data (Osman et al., 2021b; proxyDatabase.nc) assimilated using climate model (iCESM) priors and code from https://github.com/JonKing93/DASH, v.3.6.1.

Available: https://www.ncei.noaa.gov/access/paleo-search/study/33112 (Osman et al., 2021b; LGMRGMSTens.nc).

Modified: Subtracted 13.49°C (median of the most recent bin) to adjust temperature relative to 1750-1950 and added 0.03° C to adjust to 1850-1900 reference period based on PAGES 2k Consortium (2019) 10-year smoothed multi-method reconstruction (Gilbert et al., 2021; SPM1_1-2000.csv).

Gulev et al. (2021)

Data set: 1850-2020 global temperature of Gulev et al. (2021) based on mean of four instrumental data sets (HadCRUT, NOAA, Berkeley Earth, Kadow) assessed by IPCC-AR6-WGI and shown in Fig. 2.11c.

Available: https://doi.org/10.5281/zenodo.6321535 (Trewin, 2022; GMST-componentdatasets.csv).

Modified: None (1850-1900 reference period).

Lee et al. (2021)

Data set: Global temperature projections to 2300 of Lee et al. (2021) based on the MAGICC (v.7.5.0) emulator (Meinshausen et al., 2020) calibrated against the IPCC-AR6 assessed temperature to 2100 and shown in Fig. 4.40a.

Available: https://zenodo.org/record/6386979 (Nicholls et al., 2022; files with titles containing “fig-4-40” and respective SSP identifiers).

Modified: None (1850-1900 reference period).

References

Gillett, N. P., Malinina, E., Kaufman, D., Neukom, R.: Summary for Policymakers of the Working Group I contribution to the IPCC Sixth Assessment Report - data for Figure SPM.1 (v20210809). NERC EDS Centre for Environmental Data Analysis [data set], http://dx.doi.org/10.5285/76cad0b4f6f141ada1c44a4ce9e7d4bd, 2021.

Gulev, S. K., Thorne, P. W., Ahn, J., Dentener, F. J., Domingues, C. M., Gerland, S., Gong, D., Kaufman, D. S., Nnamchi, H.C., Quaas, J., Rivera, J. A., Sathyendranath, S., Smith, S.L., Trewin, B., von Shuckmann, K., and Vose, R. S.: Changing State of the Climate System, in: Climate Change 2021: 85 The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S. L., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M. I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J. B. R., Maycock, T.K., Waterfield, T., Yelekçi, O., Yu, R., and Zhou, B., Cambridge University Press, https://www.ipcc.ch/report/ar6/wg1/ downloads/report/IPCCAR6WGIChapter02.pdf, 2021.

Hansen J., Sato, M., Russell, G., and Kharecha, P.: Climate sensitivity, sea level and atmospheric carbon dioxide, Philos. T. Roy. Soc. A, 371, 20120294, https://doi.org/10.1098/rsta.2012.0294, 2013.

Kaufman, D., McKay, N., Routson, C., Erb, M., Davis, B., Heiri, O., Jaccard, S., Tierney, J., Dätwyler, C., Axford, Y., Brussel, T., Cartapanis, O., Chase, B., Dawson, A., de Vernal, A., Engels, S., Jonkers, L., Marsicek, J., Moffa-Sánchez, P., Morrill, C., Orsi, A., Rehfeld, K., Saunders, K., Sommer, P., Thomas, E., Tonello, M., Tóth, M., Vachula, R., Andreev, A., Bertrand, S., Biskaborn, B., Bringué, M., Brooks, S., Caniupán, M., Chevalier, M., Cwynar, L., Emile-Geay, J., Fegyveresi, J., Feurdean, A., Finsinger, W., Fortin, M., Foster, L., Fox, M., Gajewski, K., Grosjean, M., Hausmann, S., Heinrichs, M., Holmes, N., Ilyashuk, B., Ilyashuk, E., Juggins, S., Khider, D., Koinig, K., Langdon, P., Larocque-Tobler, I., Li, J., Lotter, A., Luoto, T., Mackay, A., Magyari, E., Malevich, S., Mark, B., Massaferro, J.,Montade,V.,Nazarova,L.,Novenko,E.,Paril,P.,Pearson,E., Peros, M., Pienitz, R., Płóciennik, M., Porinchu, D., Potito, A., Rees, A., Reinemann, S., Roberts, S., Rolland, N., Salonen, S., Self, A., Seppä, H., Shala, S., St-Jacques, J., Stenni, B., Syrykh, L., Tarrats, P., Taylor, K., van den Bos, V., Velle, G., Wahl, E., Walker, I., Wilmshurst, J., Zhang, E., and Zhilich, S.: A global database of Holocene paleo-temperature, Scientific Data, 7, 115, https://doi.org/10.1038/s41597-020-0445-3, 2020a.

Kaufman, D., McKay, N., Routson, C., Erb, M., Dätwyler, C., Sommer, P., Heiri, O., and Davis, B.: Holocene global surface temperature: A multi-method reconstruction approach, Scientific Data, 7, 201, https://doi.org/10.1038/s41597-020-0530-7, 2020b.

Kaufman, D., McKay, N., Routson, C., Erb, M., Dätwyler, C., Sommer, P., Heiri, O., and Davis, B.: NOAA/WDS Paleoclimatology – Holocene global surface temperature: A multi-method reconstruction approach, NOAA National Centers for Environmental Information [data set], https://doi.org/10.25921/vzys-1280, 2020c.

Lee, J. Y., Marotzke, J., Bala, G., Cao, L., Corti, S., Dunne, J. P., Engelbrecht, F., Fischer, E., Fyfe, J. C., Jones, C., Maycock, A., Mutemi, J., Ndiaye, O., Panickal, S., and Zhou, T.: Future Global Climate: Scenario-Based Projections and Near-Term Information, in: Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S. L., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M. I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J. B. R., Maycock, T. K., Waterfield, T., Yelekçi, O., Yu, R., and Zhou, B., Cambridge University Press, https://www.ipcc.ch/report/ar6/wg1/downloads/ report/IPCCAR6WGIChapter04.pdf, 2021.

Meinshausen, M., Nicholls, Z. R. J., Lewis, J., Gidden, M. J., Vogel, E., Freund, M., Beyerle, U., Gessner, C., Nauels, A., Bauer, N., Canadell, J. G., Daniel, J. S., John, A., Krummel, P. B., Luderer, G., Meinshausen, N., Montzka, S. A., Rayner, P. J., Reimann, S., Smith, S. J., van den Berg, M., Velders, G. J. M., Vollmer, M. K., and Wang, R. H. J.: The shared socio-economic pathway (SSP) greenhouse gas concentrations and their extensions to 2500, Geosci. Model Dev., 13, 3571–3605, https://doi.org/10.5194/gmd-13-3571-2020, 2020.

McKay, N.: nickmckay/past-and-future-warming-comparison-figure, Zenodo [code and data set], https://doi.org/10.5281/zenodo.5842209, 85 2022.

Nicholls, Z., Meinshausen, M., and Lewis, J.: AR6 WG1 plots and processing (v1.0.0), Zenodo [data set], https://doi.org/10.5281/zenodo.6386979, 2022.

Osman, M. B., Tierney, J. E., Zhu, J., Tardif, R., Halkim, G. J., King, J., and Poulsen, C. J.: Globally resolved surface temperatures since the Last Glacial Maximum, Nature, 599, 239–244, https://doi.org/10.1038/s41586-021-03984-4, 2021a.

Osman, M. B., Tierney, J. E., Zhu, J., Tardif, R., Halkim, G. J., King, J., and Poulsen, C. J.: NOAA/WDS Paleoclimatology – Globally resolved surface temperatures since the Last Glacial Maximum, NOAA National Centers for Environmental Information [data set], https://doi.org/10.25921/njxd-hg08, 2021b.

PAGES 2k Consortium (Neukom, R., Barboza, L.A., Erb, M. P., Shi, F., Emile-Geay, J., Evans, M. N., Franke, J., Kaufman, D. S., Lücke, L., Rehfeld, K., Schurer, A., Zhu, F., Brönnimann, S., Hakim, G.J., Henley, B., Ljungqvist, F. C., McKay, N., Valler, V., von Gunten, L.): Consistent multi-decadal variability in global temperature reconstructions and simulations over the Common Era. Nature Geosci., 12, 643-649. https://doi.org/10.1038/s41561-019-0400-0, 2019.

Rouston, C., McKay, N., Sommer, P. S., Dätwyler, C., and Erb, M.: nickmckay/Temperature12k: Analysis and plotting code for Temp12k Analysis Paper (1.2.0), Zenodo [code], 105 https://doi.org/10.5281/zenodo.3888590, 2020.

Snyder, C. W.: Evolution of global temperature over the past two million years, Nature, 538, 226–228, https://doi.org/10.1038/nature19798, 2016.

Trewin, B.: Global temperature time series from IPCC AR6, Zenodo [data set], https://doi.org/10.5281/zenodo.6321535, 2022.

Zachos, J.C., Dickens, G.R., and Zeebe, R.E.: An Early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics. Nature 451, 279–283, https://doi.org/10.1038/nature06588, 2008.