Emergent constraints on carbon budgets as a function of global warming

This directory contains all of the data (model output and observations) and python code necessary to recreate the plots in the Nature Communications paper : “Emergent constraints on carbon budgets as a function of global warming” by Cox, Williamson et al.

The key high-level python codes which plot the figures in the main manuscript are contained in the subdirectory ‘/FIGS’, and are:

a) MAIN_TCRE_processing.py: processes timeseries data from ESMs (in directory '../CMIP6-txt-files') and observations (in directory '../Observations'), and creates output files for plotting figures ( in directory '/outfiles').
For models, it outputs carbon budgets and global warming up to current day and at specified levels of global warming (e.g. filenames 'ssp245_T2.0_LU1.txt').
For observations, it just outputs carbon budgets and global warming up to the current day (e.g. 'Obs_T_LU1.txt').
Also creates figures of prescribed inputs ('/plots/Prescribed_inputs.pdf') and projections against time (e.g. '/plots/ssp245_Projections_v_t.pdf') and emissions (e.g. '/plots/ssp245_Projections_v_E.pdf');

b) FIGURE_2_3.py: Reads processed data (from directory '/outfiles') and creates Figures 2 and 3 (in '/plots' as 'FIGURE2_2.0.png' and 'FIGURE3_2.0.pdf');

c) FIGURE4_new.py: Reads processed data (from directory '/outfiles') and creates Figures 4 (in '/plots' as 'FIGURE4_new.pdf');

d) FIGURE5.py: Reads processed data (from directory '/outfiles') and creates Figures 5 (in '/plots' as 'FIGURE5.pdf').

Also includes timeseries data from CMIP6 models that provided the necessary land-atmosphere and ocean-atmosphere CO2 fluxes for the historical run (1850-2014) and for all of the ssp126, ssp245, ssp370, ssp585 scenario runs (2015-2100). To be consistent with the precribed CO2 runs that we use for the ssp scenarios, we use the CMIP6 historical runs (with prescribed atmospheric CO2) rather than the CMIP6 esm-hist runs (which calculate the atmospheric CO2 interactively based-on prescribed CO2 emissions). Time-series of global annual mean near surface air temperature (CMIP variable tas), Net Biome Productivity over land (CMIP variable nbp), and ocean CO2 flux (CMIP variable fgco2), were calculated from monthly spatial fields downloaded via the ESGF node (https://esgf-index1.cdea.ac.uk/projects/cmip6-ceda/) on 16 October 2020.