emulandice ///////////////////////////////

Emulator of multi-model land ice projections (Edwards et al., 2021, Nature).

Input data files (inst/extdata/):

Calibrated with ISMIP6 and GlacierMIP model projections: 20201106_SLE_SIMULATIONS.csv.

Forced with GSAT projections from:

• FAIR ensemble of McKenna et al. (2020): 20201105_CLIMATE_FORCING.csv, or

• IPCC AR6 Chapter 7 two layer model ensemble: 20210215_CLIMATE_FORCING_IPCC.csv

Prior distributions on ice sheet parameters derived from:

• Greenland retreat: data_for_tamsin.txt

• Antarctic basal melt: output_gamma0_NonLocal_MeanAnt.dat and output_gamma0_NonLocal_PIGL.dat

Below is the list of commands to run the analyses. OK to have this message on running: "There were 50 or more warnings (use warnings() to see the first 50)"

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MAIN PROJECTIONS

Edwards et al. (2021) ////////////////////////////////////

Main projections: 2100

Set N_temp because default for timeslice is 1000 (for sensitivity tests)

main(N_temp = 5000L)

Main projections: full timeseries

main("timeseries")

Antarctic projections: subset of models in LARMIP and ISMIP6

main(N_temp = 5000L, select_ism == "larmip")

IPCC AR6 Chapter 9 ///////////////////////////////////////

Main projections: 2100

Set N_temp as above

main(dataset = "IPCC", N_temp = 10000L)

Main projections: full timeseries

Run 2-3 SSPs at once for timeseries because 4x larger ensembles than main FAIR projections

main("timeseries", dataset = "IPCC", fair_ssps = c("SSP126", "SSP585"))

main("timeseries", dataset = "IPCC", fair_ssps = c("SSP119", "SSP245", "SSP370"))

Antarctic projections: subset of models in LARMIP and ISMIP6

main(dataset = "IPCC", N_temp = 10000L, select_ism = "larmip")

main("timeseries", dataset = "IPCC", fair_ssps = c("SSP126", "SSP245", "SSP585"), select_ism = "larmip")

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COVARIANCE FUNCTION TESTS

Each sets same covariance function for all regions

Default covariance (plus model comparison)

main("SA", do_model_comp = TRUE, do_covar_fn = "matern_5_2")

Alternative covariances

main("SA", do_covar_fn = "matern_3_2")

main("SA", do_covar_fn = "pow_exp", do_covar_alpha = 1.9)

main("SA", do_covar_fn = "pow_exp", do_covar_alpha = 1.0)

main("SA", do_covar_fn = "pow_exp", do_covar_alpha = 0.1)

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SENSITIVITY ANALYSIS

Main sensitivity analysis

main("SA")

Simulation data plots

main("sim_only")

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SENSITIVITY TESTS: Extended Data Figure 4

S2 CMIP6 ensemble for GSAT

main("CMIP6")

S3 Fixed GSAT

main("fixed_T")

S4 Fixed ice sheet retreat and basal melt

main("fixed_melt")

S5-8 Basal melt priors

main("gamma0_MeanAnt", ice_sources = "AIS")

main("gamma0_PIGL", ice_sources = "AIS")

main("gamma0_unif", ice_sources = "AIS")

main("gamma0_unif_high", ice_sources = "AIS")

S9-10 Ice shelf collapse priors

main(collapse_prior = "off")

main(collapse_prior = "on")

S11 Risk-averse projections: SA, 2100 and full timeseries

main("SA", risk_averse = TRUE)

main(risk_averse = TRUE, N_temp = 5000L)

main("timeseries", risk_averse = TRUE)

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ROBUSTNESS TESTS: Extended Data Figure 5

SA are to check nothing strange happens using smaller datasets

(check Tdep, meltdep plots)

R2 Minimum ice sheet resolution

main("SA", min_res_is = c(8,30))

main("high_res")

R3 More balanced ice sheet model designs

main("SA", select_ism = "balanced")

main(select_ism = "balanced")

R4 One ice sheet model

main("SA", select_ism = "single")

main(select_ism = "single")

R5 Further Antarctic ice sheet model (low sensitivity)

main("SA", select_ism = "single_low")

main(select_ism = "single_low")

R6 Subset of Antarctice ice sheet models with high sensitivity

main("SA", select_ism = "high_sensitivity")

main(select_ism = "high_sensitivity")

R7 Subsets of climate models driving Antarctic ice sheet models

main("SA", select_gcm = "high_five")

main(select_gcm = "high_five")

main("SA", select_gcm = "high_two")

main(select_gcm = "high_two")

R8 History matching with Antarctic observational trend

main("SA", history_match = TRUE)

main(history_match = TRUE)

R9 Exclude Antarctic models not using parameterisation

main("SA", exclude_open = TRUE)

main(exclude_open = TRUE)

R10 Use higher value for missing basal melt

main("SA", impute_high = TRUE)

main(impute_high = TRUE)