ESM Working group: Meeting notes 2026

Earth System Working Group
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6

Date: 9/6/2026
Chair: @tiloz
Participants: 13

1. Admin and resource usage

  • Science Presentations: The last couple of meetings have been cancelled due to there being no science presentations. Several spaces are available for presentations at future ESM WG meetings. If you have any work that you would like to share with the community, please get in contact the ESM WG co-chairs @dkhutch, @tiloz, @ShayneM, @ctychung or @spencerwong. Presentations from recent conferences and workshops are welcome, as are informal updates on in progress work.

  • LG87 Resource Usage:

    • 1.88 MSU out of the 2MSU compute allocation has been used. The working group compute allocations have been increased this quarter, and there is an additional pool available which will be distributed to the working groups on a first-come-first-serve basis. If you have experiments you are interested in running, it is a good idea to add a proposal early in the quarter as this helps with resource allocation.
    • If you have any experiments you are interested in running with ESM WG resources next quarter, follow the proposal guidelines here to apply to use WG compute.
    • /g/data/lg87 has reduced from 94 TB to 63 TB out of the 100 TB allocation. Many thanks to everyone who cleaned up data. If you have any data in /g/data/lg87 it would still be much appreciated if you can clean up anything that is no longer required.
    • If you are interested in using working group resources to run CMIP7 experiments, please get in contact with @RachelLaw. Please see this topic for a list of the available experiments.

2. ESM1.6 and CMIP7

  • ACCESS-ESM1.6 production runs for CMIP7 are underway, with focus now shifting from the control and idealised simulations to the historical experiments. An overview of the status of the different experiments is available here. You are welcome to look at the output and get involved with the ongoing discussions and analysis.
  • A CMIP7 meeting on coordinating the analysis and evaluation effort was recently held. A future catch up could be hosted during the WG meetings.

Status of ACCESS-ESM1.6 experiments - CMIP7 / CMIP7 MIPs and other experiments - ACCESS Hive Community Forum

3. ACCESS Community Workshop on Land and Coupled Modelling

  • Abstract submissions for the ACCESS Community Workshop on Land and Coupled Modelling close at midnight AEST June 15.** If you would like to submit an abstract for a presentation or poster, please submit your abstract here.

4. Science presentation: Missing Antarctic meltwater: Implications for Southern Hemisphere climate projections

@wghuneke presented on the impact of Antarctic meltwater on the Southern hemisphere in coupled climate models.

Background:

  • The Antarctic ice sheet and its interactions with the ocean are not well represented in current climate models. For example, basal meltwater is typically prescribed and lacks variability and feedbacks.
  • Recent climate model experiments show that there is large uncertainty around the effects of Antarctic meltwater on the climate.
  • The SOFIA freshwater experiments comprise of 6 idealised meltwater experiments, with the aim of allowing for multimodel analysis. This presentation discusses results from the SOFIA antwater experiments, where 0.1 Sv of freshwater is added around the Antarctic coastline.

Results:

  • Ocean: The added freshwater consistently causes surface cooling, subsurface warming, and a reduction in Antarctic bottom water formation which varies across the model. The magnitude and pattern of surface cooling also varies across the models, however doesn’t correlate with the magnitude of the changes in deep convection
  • Sea ice: Sea ice area increases in all models, with magnitude and spatial variations depending on the models’ mean states.
  • Atmosphere: Cooling in the troposphere is strongest around Antarctica, however spreads to the northern hemisphere. Strengthened westerlies are seen in the southern hemisphere.
  • Tropics: The meltwater produces a spatial pattern of cooling in the tropics and leads to a northward shift of the ITCZ.

Impact on southern hemisphere land masses

  • Compared to the SSP2-4.5 experiments, the antwater experiments largely produce opposite signed responses in temperature and precipitation. The additional meltwater is expected to damp temperature increases over southern hemisphere land masses. nLarge spreads occur within each model, and across the models, emphasising the importance of using multiple models and as large ensembles as possible.
  • Precipitation responses are generally not significant for the current number of ensemble members, and the models do not agree on the sign of the changes, with the only robust response being drying over Antarctica.
  • The magnitude of cooling and drying over Antarctica strongly correlate with the change in air temperature over the southern ocean, highlighting potential feedbacks onto melting.

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

Additional information