New LULCC data for CMIP7

[wwieder]

New LULCC data have been released for CMIP7, including:

Updated HIST data (downloaded April 16, 2026)

/glade/campaign/cesm/cesmdata/input4MIPs_raw/input4MIPs/CMIP7/CMIP/UofMD/UofMD-landState-3-1-2

• @lawrencepj1 do we need to update our surface datasets and historical land use timeseries?

Updated ScenarioMIP

/glade/campaign/cesm/cesmdata/input4MIPs_raw/input4MIPs/CMIP7/ScenarioMIP/CR/

• @lawrencepj1, is there preprocessing needed before @slevis-lmwg makes scenarios for the scenarios?

• @slevis-lmwg makes the new datasets

[ekluzek]

We will meet with @lawrencepj1 next week. @slevis-lmwg will make datasets after the conversion is done and we've got this figured out.

One thing to figure out is how extensive the change in historical datasets are, and if it's worth doing at this point. As doing that will require making all new datasets, and getting them into the XML.

[slevis-lmwg]

From meeting with @lawrencepj1 and @ekluzek

• Peter recommends consistency between historical and scenarios, so he recommends doing all of it
• Peter will plan on having the raw datasets available by May 25, so that Sam L. may start generating fsurdat/landuse files (Sam starts PTO on June 9)
• Sam to start CLM6 offline and coupled, plus FATES testing
• Peter and Erik will proceed with minor version release ctsm5.5
• @wwieder @dlawrenncar pinging you since this plan potentially affects CESM3 spin-ups

Notes
What's new about CMIP7 datasets

[olyson]

@slevis-lmwg , will we need to update the raw urban datasets?

[slevis-lmwg]

Keith's question led me to this documentation:
https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/land-use/
which states

Summary
Note that v3.1.1 of the historical land-use forcing and v3.1 of the scenario land-use forcing have been superseded. However, the
updates are only to metadata so, if you have already run simulations using the v3.1.1 historical land-use forcing or v3.1 scenario
land-use forcing, you do not need to re-run with the newer datasets

This may be good news if we have been using v3.1 or v3.1.1 so far.
@lawrencepj1 please confirm.
In this case I'm pretty sure that we can skip the time consuming steps of redoing historical and making a new minor version release.