Final Report: CMIP7 Workshop

May 3, 2023

Read the report of the outcomes of the CMIP7 Workshop: updates and challenges, which took place in CSIRO Aspendale for two days at the end of February. The workshop was co-hosted by the Australian Earth System Simulator (ACCESS-NRI), CSIRO, the NESP Climate Systems Hub and the National Computational Infrastructure (NCI).

Final Report – CMIP7 Workshop

As a globally-coordinated shared resource, CMIP is widely used for research and in producing information for decision-makers, including through national and state climate projections. The 2021 Intergovernmental Panel on Climate Change (IPCC) sixth assessment report featured climate models from CMIP6, while the upcoming IPCC seventh assessment report (AR7) will feature new state-of-the-art CMIP7 models. For CMIP6, Australia submitted two (ACCESS-CM2 and ACCESS ESM1.5) primary model configurations, developed by CSIRO.

The aims of this workshop were:

Discuss amongst the community the status of current plans for CMIP7
Compare Australia’s current approach with other nations, and with CMIP5/6
Discuss the influence, importance and impact of having an Australian climate model in CMIP7 and the current climate & Earth system model landscape for Australia
Frame a community-wide strategy for Australia’s CMIP7 contributions, including resourcing requirements
Discuss what questions we hope to address with CMIP7 as a community
Consider future needs for the use of CMIP in conjunction with other tools – emulators, machine learning, k-scale modelling, downscaling simulations

The outcomes of the workshop included:

The workshop involved constructive discussions around whether, why and how Australia could contribute to CMIP7.
There was strong support from the attendees to encourage a strong CMIP7 contribution, with the primary motivations including:

Create models that represent climate processes that are important for Australia and the Southern
Hemisphere
Maintain existing, and train new modellers, to provide essential capability for climate and weather models
Sovereign capability and expertise to identify suitable climate policies, and to contribute to the tools needed for decision–making on climate mitigation and adaptation for Australia
Provision of accurate sea level and climate forecasts to regional neighbours, particularly Pacific Island States
Focal point for climate model development
International collaboration and leveraging rigorous scientific evaluation through broader intercomparison of the ACCESS models
Visibility of Australia’s effort through CMIP7 to the next IPCC assessment report
Bringing together and expanding Australia’s earth systems modelling community
Have an influence on the CMIP process
Make explicit the requirements of the global models (ACCESS) for regional downscaling or other downstream use of the data.

In the past, Australia has had successful CMIP contributions (for example, ACCESS–ESM1.5 is the 4th most downloaded model in CMIP6) which has supported our research community and contributed to our international reputation in climate science. But the recent Australian CMIP effort has been under–resourced compared to other international groups and was overly reliant on the expertise of several key individuals who made enormous contributions.

Australia is already playing a strong role in the CMIP7 process, through membership on the CMIP panel and 5 of 6 Task Teams to set up the forcings, data processes and coordination for CMIP7. These memberships are sourced from a range of Australian institutions/universities and represent a cross–section of career stages.

The key elements of Australia’s CMIP7 process include engagement with the international community about forcing, endorsed experiments and data protocols through the CMIP7 Task Teams, as well as the urgent need to create a system for model testing and evaluation with rapid feedback to the development process.

The decision on model development pathways is complex, and may involve a “minimal” development pathway, an ambitious single–model strategy, or a twin strategy that supports multiple model configurations (as in CMIP5 and CMIP6). The level of ambition on the model development will depend upon the resource available and the CMIP7 timelines (which remain unclear). For any type of submission, the resource required to conduct computations, store the CMIP7 archive and support users (even beyond the CMIP7 timeline) need to be considered.

There was broad support for greater community involvement in Australia’s CMIP7 submission, given the potential for CSIRO to work with the ACCESS–NRI, NCI and other partners to facilitate that community involvement, potentially through a consortium approach.

The meeting participants identified the following next steps:

To finalise a meeting report (this document)
To form a small working group to explore the scope of a community approach and to begin preparing supporting material (value proposition, business case, options for model development/configurations) along with identifying existing capacity and gaps. The group should include early career scientists and a diverse range of contributors