ESM working group: Meeting notes 2024

Earth System Working Group
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37

Date: 13/3/2025
Participants: 12
Chair: @ShayneM

  1. 2025 ACCESS-NRI Community Workshop Training Day Poll:
  • @jasmeen_kaur introduced the online poll for voting on training topics for the Training Day at the ACCESS-NRI Community Workshop.
  • The poll is available here and voting is open until the 31st of March.
  1. Upcoming Science Presentations
  • Science presentations from Hannah Dawson and Wilma Huneke are scheduled for the next March 27 and April 10. . will be Shayne McGregor emphasized the importance of science presentations and encouraged contributions from both researchers and students.
  • Community members are encouraged to present at the working group meetings. Presentations can be on works in-progress, and students are especially encouraged to present.
  1. Shared Resources and Experiments:
  • ESM project lg87 has used 535 KSU of its 875 KSU allocation for this quarter. /g/data storage remains at 54.3TB
  • Georgina Falster is currently running experiments with ACCESS ESM1.5, which will likely use up the remaining compute for this quarter.
  • Do you have any proposals for shared experiments? See guidelines for how to do this. There are often used resources we can access if there are projects to use them.
  1. Science Presentation:

  • Liam Cassidy, a PhD candidate at the University of Melbourne, presented his research on temperature extremes under net zero CO2 conditions. His work focuses on understanding regional climate changes and temperature extremes after achieving net zero CO2 emissions.

  • The research utilized data from the Zero Emissions Commitment Model Intercomparison Project (ZECMIP), which includes idealized experiments to understand global and regional climate responses to net zero CO2 emissions. Experiments from the MIROC-ES2L, UKESM1-0-LL, and ACCESS-ESM1.5 models were compared.

  • The study analyzed three branching experiments based on cumulative CO2 emissions levels: 750, 1000, and 2000 petagrams, involving an initial phase of increasing CO2 emissions (1% per year) followed by an instantaneous transition to net zero emissions.

  • The study compared temperature and precipitation anomalies, as well as the scaling of temperature extremes, between the warming and net zero periods.

  • Findings:

    • Significant model diversity was observed in regional temperature changes after net zero emissions. Some models showed cooling over land, while others indicated continued warming, particularly in the 2000 petagram scenario. However, models were consistent in showing Southern Ocean warming after net zero.
    • Localized cooling was often associated with increased precipitation, while warming regions tended to experience decreased precipitation.
    • TXx scaling was investigated to understand whether changes in regional hydrology impact changes in temperature extremes after net-zero. TXx scaling generally decreased after net zero, though changes were heterogeneous in space with diversity between the models.
    • Focusing on South Africa, changes in westerly wind patterns, precipitation, and soil moisture changes were linked to changes in temperature extremes. The study highlighted the importance of understanding local feedback mechanisms, such as soil moisture and evaporative fraction, in moderating temperature extremes, as well as the value of taking a storylines approach for analysis.

These notes were partially generated by AI. If you notice any errors or omissions please feel free to modify directly, or message @spencerwong.

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