Technical Summary of the Working Group I Contribution to the IPCC Sixth Assessment Report - notes on reproducing Figure TS.1 v20221110

Notes on reproducing Figure TS.1 from the provided data.

Top row of figure (CO2 concentrations) is related to:

-- Paleo data are from Figure 2.3 and 2.4 (section 2.2.3):
. Paleo 60–1 million years data are from Figure 2.3 (section 2.2.3), compiled data provided in this dataset,
. Paleo and direct measurements 800 thousand years to 1980 CE data are from Figure 2.4 (section 2.2.3), input data references in the input data table 2.SM.1 of the Supplementary Material for Chapter 2.

-- 2300 emissions scenarios are described in section 4.7.1:
. Data link provided in Related Documents section of this catalogue record (https://zenodo.org/record/6386979#.YnAJPy-cb-E).

Bottom row of figure (global mean surface temperature) is related to:

-- Paleo data are from Cross-Chapter Box 2.1, Figure 1:
. 60 –1 million years from Hansen et al., (2013)
. 800 to 0 thousand years from Snyder, (2016).
. Data are archived at CEDA and link provided in Related Records section of this catalogue record (https://catalogue.ceda.ac.uk/uuid/0f05c2fb8f814d60ac2d657a70e9a7f5).

-- Direct measurements are from Figure 2.11 (section 2.3.1):
. Data are archived at CEDA and link provided in Related Records section of this catalogue record (https://catalogue.ceda.ac.uk/uuid/f3515388768344bfb2be0521f82388be).

-- 2300 projections are from Figure 4.40a (section 4.7.1):
. Data link provided in Related Documents section of this catalogue record (https://zenodo.org/record/6386979#.YnAJPy-cb-E).

Maps of surface air temperature are related to:

-- Early Eocene and mid-Pliocene are from Figure 7.13, data are archived at CEDA and link provided in Related Records section of this catalogue record.
-- 2020 in this dataset
-- 2100 and 2300 projections in this dataset.

Early Eocene:
The background map (model) is the same as Figure 7.13a, and the data points (proxies) are the same as Figure 7.13a (circles) and Figure 7.13j (squares). The data for the model map comes from Lunt et al (2021). The model output is in the supp info of that paper, https://cp.copernicus.org/articles/17/203/2021/cp-17-203-2021-supplement.zip; . We only include those simulations which were carried out with CO2 in the IPCC assessed range, that is:

N=5: CESM1.2_CAM5-deepmip_stand_6xCO2 , COSMOS-landveg_r2413-deepmip_sens_4xCO2 , GFDL_CM2.1-deepmip_stand_6xCO2 , GFDL_CM2.1-deepmip_sens_4xCO2 , INM-CM4-8-deepmip_stand_6xCO2

Note that an anomaly is shown, relative to the zonal mean of the ensemble mean preindustrial control (also available from the same source).

The proxies are from Hollis et al (2019), but only those sites that were deemed to not be affected by diagenesis. Data and metadata for these sites are in Inglis et al (2020).

Mid-Pliocene:
The background map (model) is the same as Figure 7.13b, and the data points (proxies) are the same as Figure 7.13b (circles) and Figure 7.13k (squares). The data for the model map comes from Haywood et al. (2020). The model output is in the PlioMIP database (for details see Chapter 2 Supplementary Material Table 2.SM.1, Cross-Chapter Box 2.4). In addition we also included one model published after Haywood et al., described in Williams et al. (2021), which is available on the ESGF. The simulations are:

N=17: CCSM4 , CCSM4-UoT . CCSM4-Utrecht , CESM1.2 , CESM2.0 , COSMOS , EC-Earth3.3 , GISS-E2-1-G , HadCM3 , HadGEM3 , IPSL-CM6A-LR , IPSLCM5A , IPSLCM5A2 , MIROC4m , MRI-CGCM2.3 , NorESM-L , NorESM1-F

Note that an anomaly is shown, relative to the ensemble mean preindustrial control (also available from the same sources).

The proxies are from McClymont et al (2020; squares) and Salzmann et al (2013; circles; only those sites that fall within the time window of the Km5c PlioMIP time slice).

SSPs:

The SSP map plots were produced in the following way:

- For 2300, the means plotted are Years 2281-2300 minus 1850-1900.
- For 2100, the means plotted are Years 2081-2100 minus 1850-1900.

The SSPs are 5-8.5 and 1-2.6.

The multi-model ensemble mean is based on models with 2300 simulations of both these SSPs at the time of making the plot:

CanESM5 , IPSL-CM6A-LR , MRI-ESM2-0 , CESM2-WACCM , UKESM1-0-LL.

All available from the ESGF – SSP simulations and historical simulations.

2020:
The methodology for this maps is in Hawkins et al (2020), and is based on regression of local temperatures on the global mean.

References :

Hansen, J., M. Sato, G. Russell, and P. Kharecha, 2013: Climate sensitivity, sea level and atmospheric carbon dioxide. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 371(2001), 20120294, doi:10.1098/rsta.2012.0294.

Hawkins, E., Frame, D., Harrington, L., Joshi, M., King, A., Rojas, M., and Sutton, R, 2020: Observed emergence of the climate change signal: From the familiar to the unknown. Geophysical Research Letters, 47, e2019GL086259. doi:10.1029/2019GL086259.

Haywood, A. M., Tindall, J. C., Dowsett, H. J., Dolan, A. M., Foley, K. M., Hunter, S. J., Hill, D. J., Chan, W.-L., Abe-Ouchi, A., Stepanek, C., Lohmann, G., Chandan, D., Peltier, W. R., Tan, N., Contoux, C., Ramstein, G., Li, X., Zhang, Z., Guo, C., Nisancioglu, K. H., Zhang, Q., Li, Q., Kamae, Y., Chandler, M. A., Sohl, L. E., Otto-Bliesner, B. L., Feng, R., Brady, E. C., von der Heydt, A. S., Baatsen, M. L. J., and Lunt, D. J., 2020: The Pliocene Model Intercomparison Project Phase 2: large-scale climate features and climate sensitivity. Climate of the Past, 16, 2095-2123. doi:10.5194/cp-16-2095-2020.

Hollis, C. J., Dunkley Jones, T., Anagnostou, E., Bijl, P. K., Cramwinckel, M. J., Cui, Y., Dickens, G. R., Edgar, K. M., Eley, Y., Evans, D., Foster, G. L., Frieling, J., Inglis, G. N., Kennedy, E. M., Kozdon, R., Lauretano, V., Lear, C. H., Littler, K., Lourens, L., Meckler, A. N., Naafs, B. D. A., Pälike, H., Pancost, R. D., Pearson, P. N., Röhl, U., Royer, D. L., Salzmann, U., Schubert, B. A., Seebeck, H., Sluijs, A., Speijer, R. P., Stassen, P., Tierney, J., Tripati, A., Wade, B., Westerhold, T., Witkowski, C., Zachos, J. C., Zhang, Y. G., Huber, M., and Lunt, D. J., 2019: The DeepMIP contribution to PMIP4: methodologies for selection, compilation and analysis of latest Paleocene and early Eocene climate proxy data, incorporating version 0.1 of the DeepMIP database, Geoscience Model Development, 12, 3149-3206, doi:10.5194/gmd-12-3149-2019.

Inglis, G. N., Bragg, F., Burls, N. J., Cramwinckel, M. J., Evans, D., Foster, G. L., Huber, M., Lunt, D. J., Siler, N., Steinig, S., Tierney, J. E., Wilkinson, R., Anagnostou, E., de Boer, A. M., Dunkley Jones, T., Edgar, K. M., Hollis, C. J., Hutchinson, D. K., and Pancost, R. D., 2020: Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene-Eocene Thermal Maximum (PETM), and latest Paleocene. Climate of the Past, 16, 1953-1968. doi:10.5194/cp-16-1953-2020.

Lunt, D. J., Bragg, F., Chan, W.-L., Hutchinson, D. K., Ladant, J.-B., Morozova, P., Niezgodzki, I., Steinig, S., Zhang, Z., Zhu, J., Abe-Ouchi, A., Anagnostou, E., de Boer, A. M., Coxall, H. K., Donnadieu, Y., Foster, G., Inglis, G. N., Knorr, G., Langebroek, P. M., Lear, C. H., Lohmann, G., Poulsen, C. J., Sepulchre, P., Tierney, J. E., Valdes, P. J., Volodin, E. M., Dunkley Jones, T., Hollis, C. J., Huber, M., and Otto-Bliesner, B. L., 2021: DeepMIP: model intercomparison of early Eocene climatic optimum (EECO) large-scale climate features and comparison with proxy data. Climate of the Past, 17, 203-227, doi: 10.5194/cp-17-203-2021.

McClymont, E. L., Ford, H. L., Ho, S. L., Tindall, J. C., Haywood, A. M., Alonso-Garcia, M., Bailey, I., Berke, M. A., Littler, K., Patterson, M. O., Petrick, B., Peterse, F., Ravelo, A. C., Risebrobakken, B., De Schepper, S., Swann, G. E. A., Thirumalai, K., Tierney, J. E., van der Weijst, C., White, S., Abe-Ouchi, A., Baatsen, M. L. J., Brady, E. C., Chan, W.-L., Chandan, D., Feng, R., Guo, C., von der Heydt, A. S., Hunter, S., Li, X., Lohmann, G., Nisancioglu, K. H., Otto-Bliesner, B. L., Peltier, W. R., Stepanek, C., and Zhang, Z., 2020: Lessons from a high-CO2 world: an ocean view from  ∼ 3 million years ago. Climate of the Past, 16, 1599–1615. doi:10.5194/cp-16-1599-2020.

Salzmann, U., Dolan, A., Haywood, A., Chan, W.-L., Voss, J., Hill, D., Abe-Ouchi, A., Otto-Bliesner, B., Brag, F., Chandler, M., Contoux, C., Dowsett, H., Jost, A., Kamae, Y., Lohmann, G., Lunt, D., Pickering, s., Pound, M., Ramstein, G., Rosenbloom, N., Soh, L., Stepanek, C., Ueda, H., and Zhang, Z., 2013: Challenges in quantifying Pliocene terrestrial warming revealed by data–model discord. Nature Climate Change, 3, 969–974. doi:10.1038/nclimate2008.

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

Williams, C. J. R., Sellar, A. A., Ren, X., Haywood, A. M., Hopcroft, P., Hunter, S. J., Roberts, W. H. G., Smith, R. S., Stone, E. J., Tindall, J. C.,and Lunt, D. J., 2021: Simulation of the mid-Pliocene Warm Period using HadGEM3: experimental design and results from modelmodel and modeldata comparison. Climate of the Past, 17, 21392163. doi:10.5194/cp-17-2139-2021.

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