ESM Working group: Meeting notes 2026

Earth System Working Group
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Notes from each meeting of the ESM Working Group are added as a reply to this topic.

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Archived meeting notes:

2023
2024/2025

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Date: 3/2/2026
Chair: @tiloz
Participants: 16

1. Admin and resource usage

  • Welcome back: Welcome back to the ESM WG meeting series. As discussed towards the end of last year, meetings have now fully swapped to the Tuesday 10:30AM schedule, and will alternate each fortnight with the CM3 evaluation and development meetings. Make sure to follow this topic , as announcements for both types of meetings will be made there.

  • Science Presentations: We don’t have any science presentations lined up for this year, and so if you have any work that you would like to share during the ESM WG meetings, please get in contact the ESM WG co-chairs or @spencerwong. Presentations from recent conferences and workshops are welcome, as are informal updates on in progress work.

  • LG87 Resource Usage:

    • Compute allocations for each working group have been doubled to 1.5MSU this quarter. 1MSU of the ESM WG’s allocation has been assigned to proposed experiments, leaving a large amount available for additional proposals. With the increase this quarter, there may be large amounts of compute available for rebalancing from other working groups at the end of the quarter, and so if you have any experiments to run, it’s a good time to put up a proposal and get them running.
    • If you have any experiments you are interested in running with ESM WG resources, follow the proposal guidelines here to apply to use WG compute.
    • Storage usage at 65 TB of 100 TB allocation.

  • Next CM3 dev-eval meeting cancelled: The CM3 dev-eval meeting scheduled for 17 February has been cancelled as it clashes with AMOS. There will be an ESM WG meeting two weeks later on 3 March followed by a CM3 dev-eval meeting on 17 March.

  • Shared calendar invite for meetings: The shared calendar for ESM WG/CM3 Dev-eval meetings has now been updated. If you were already subscribed, the meeting invitations should now have the correct times (contact @spencerwong if there are any issues).

    If you aren’t already subscribed, please follow the instructions on the how to subscribe to a calendar feed page using the calendar URL https://outlook.office365.com/owa/calendar/463c5a6d0bba4c838dce9c57933398fb@anu.edu.au/3086e7a51b0d48ef85bee981a597274413647516456690471131/calendar.ics to add the shared calendar to your preferred application.

    The above instructions will be added in a post on the announcement page.

3. ESM1.6 updates

  • @tiloz and @RachelLaw presented updates on the ESM1.6 simulations completed over the holiday period. Key updates include the resolution of the ocean temperature drift with the ocean albedo decrease, updates to all CMI7 forcings other than ozone, and performance improvements compared to ESM1.5, with a ~40-45% increase in throughput for the same compute cost.
  • Updated configurations tested over the holiday period include: concentration driven picontrol, emissions driven picontrol, fully coupled, bgc-only, and radiation only 1%CO2 simulations, 4xCO2, flat10, and historical simulations.
  • An issue was identified in the land BGC: BGC only 1%CO2 simulations did not show the expected magnitude of increase in land carbon uptake. This has been attributed to a bug in the phosphorous leaching parameter, which depleted the phosphorus pools available to plants. This bug has now been fixed, and new simulations with increased initial pools are being run. Carbon-nitrogen only simulations are also being tested, which display the expected levels of carbon uptake.
  • Historical simulations produce a similar climate to ESM1.5, however the land carbon cycle is quite different. Several tests are being run with different settings for phosphorous limitation, wood harvests, and initial pool sizes, to help with tuning the configuration.
  • Outputs from these test simulations are available for analysis in the following locations:
    • December spinup (CNP): /g/data/p73/archive/CMIP7/ACCESS-ESM1-6/spinup/Dec25-PI-control
    • December spinup emissions driver (CNP): /scratch/p66/txz599/access-esm/archive/esm-pi-01-expt-4a4edd44
    • December spinup (CN): /g/data/p73/archive/CMIP7/ACCESS-ESM1-6/spinup/Dec25-PI-CN
    • Spinup test with phosphorous bug fix (CNP): /scratch/p66/txz599/access-esm/archive/test_pi_plss_02-expt-a9acd03a
    • 1%CO2 (CNP + phosphorous bug fix): /scratch/p66/txz599/access-esm/archive/test_1pct_04-expt-2cb54419
    • 1%CO2 (CN): /scratch/p66/txz599/access-esm/archive/testCN_1pctco2-expt-0bf72499
    • 4xCO2 (CNP with phosphorous bug): /scratch/p66/txz599/access-esm/archive/4xCO2-01-expt-822dff3c
    • Historical (CNP with phosphorous bug): /scratch/p66/rml599/access-esm/archive/hist-restart170-hist-restart170-78be432c
    • Historical (CN): /scratch/p66/rml599/access-esm/archive/test-hist-CN-test-hist-CN-3e80d641
    • Historical (CNP + phosphorous bugfix): /scratch/p66/rml599/access-esm/archive/test-hist-fixedP-test-hist-fixedP-4af5fa4d

Please feel free to correct any mistakes in these notes directly, or message @spencerwong with corrections.

Additional information