Add email archive

[znichollscr]

Description

Checklist

Please confirm that this pull request has done the following:

• Data released on ESGF N/A
• ESGF update pulled in here N/A
• Documentation added (where applicable)
• Changelog item added to changelog/
• Did a new release after merging: https://github.com/PCMDI/input4MIPs_CVs/releases/tag/v6.7.24

[znichollscr]

@eleanororourke

[durack1]

Nice @znichollscr centralising all this info in one place makes sense to me, and pulls (or at least duplicates) info out of inboxes - as my llnl.gov email is now dead, I have no personal track of these comms that occurred via email in CMIP6, only my version tracking in the CMIP6 Forcing Datasets Summary

[eleanororourke]

2026-01-17 update

Historical forcings

CMIP7 datasets for AR7 Fast Track
The CMIP Forcings Task Team have been working exceptionally hard and anticipate all piControl and historical CMIP7 DECK forcing datasets to be available for use by 28th February 2025, except for the historical ozone concentrations and nitrogen deposition datasets, which are expected in May 2025.

CMIP6Plus testing datasets
A number of CMIP6Plus preliminary forcing datasets have already been made available via ESGF through the input4MIPs project and are ready for testing by any interested modelling centres or data analysts. We encourage users to test the available datasets and provide feedback via the input4MIPs_CVs repository discussions on GitHub (https://github.com/PCMDI/input4MIPs_CVs/discussions).

For further details on the CMIP DECK forcing suite please see the CMIP Forcings Task Team webpage, the recent open community drop-in session slides and recording, and the input4MIPs documentation repository (https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/)

PLEASE NOTE: All CMIP6Plus era data sets are for testing purposes only, i.e. they are not to be relied upon for CMIP7 production runs.

Scenarios and harmonisation

We anticipate some scenario forcings datasets may be available for testing as early as April 2025 with others expected by October 2025. With the ScenarioMIP description manuscript now out for review, we anticipate final scenario forcing datasets to be available once the ScenarioMIP team has finalized the protocol and the participating socioeconomic modelling teams (i.e. Integrated Assessment Models, or IAMs) have produced scenarios in line with this protocol. The Forcings Task Team is working on establishing a firmer timeline for the scenario forcing delivery and is at the final stages of planning for the harmonisation, which is part of providing scenario forcings.

[eleanororourke]

2025-01-31 update

Update on CMIP6Plus stratospheric aerosol optical property and volcanic sulfur emission datasets

Version 1.3.0 of the CMIP6Plus stratospheric aerosol optical property and volcanic sulfur emission datasets are now available on ESGF with succinct documentation available here. A key development in this version is the addition of small-magnitude volcanic eruption pre-satellite era, addressing an important bias in previous versions. This development means that the piControl climatology for stratospheric aerosol optical properties should be very stable from now on, and that if you start spinning up your model with this version, we expect minor effects when you implement future updates, including the final version that will be frozen for use in the AR7 Fast Track at the end of February. We encourage users to test the available datasets and provide feedback via the input4MIPs_CVs repository discussions on GitHub.

[eleanororourke]

2025-03-27 update

The CMIP Forcings Task Team would like to provide an update on the availability of CMIP7 forcings datasets:

• CMIP7 Anthropogenic short-lived climate forcer (SLCF) and CO2 emissions data is now available.
• For models with interactive chemistry, all data sets required for piControl and historical simulations are now available.
• For models that require ozone and nitrogen deposition as inputs, we expect ozone and nitrogen deposition piControl datasets to be available before the end of April.
• Please see https://wcrp-cmip.org/cmip-phases/cmip7/cmip7-forcing-datasets/ for links to the data, where and how to feedback, and how to ensure you stay updated on the latest announcements.

[eleanororourke]

2025-04-15 update

IMPORTANT: Errors in Table 1 of Dunne et al, 2025

We are aware that some of you are already following the An evolving Coupled Model Intercomparison Project phase 7 (CMIP7) and Fast Track in support of future climate assessment preprint Table 1. Some errors have been found regarding the volcanic and solar forcing entries, which will be corrected for final submission, and are highlighted in bold below:

 

Experiment short name	Experiment description	Anthropogenic Forcing	Volcanic Forcing	Solar Forcing	Start Year	End Year	Main purpose
amip	Atmosphere with SSTs and SICs prescribed	Time-varying	Time-varying	Time-varying	1979	2021	Evaluation, SST/sea ice forced variability
piControl and/or esm-piControl	Coupled atmosphere-ocean pre-industrial control	All 1850, CO2 prescribed concentration or zero emissions	Fixed mean radiative forcing matching historical simulation (i.e. 1850–2021 mean)	Fixed mean value matching first two solar cycles of the historical simulation (i.e. 1850–1873 mean)	1	400+	Evaluation, unforced variability
abrupt- 4xCO2	CO2 prescribed to 4 times preindustrial	Same as piControl except CO2 concentration prescribed to 4 times piControl	Same as piControl	Same as piControl	1 (branching from year 101 or later of piControl)	300+ (1000)	Equilibrium climate sensitivity, feedback, fast responses
1pctCO2	CO2 prescribed to increase at 1% yr-1	Same as piControl except CO2 prescribed to increase at 1% yr-1	Same as piControl	Same as piControl	1 (branching from year 101 or later of piControl)	150	Transient climate sensitivity
historical and/or esm-hist	Simulation of the recent past	All time varying, CO2 prescribed concentration or emission	Time varying	Time varying	1850	2021	Evaluation
piClim-Control (amip)	Preindustrial conditions including SST and SIC prescribed	All 1850, CO2 prescribed concentration	Same as piControl	Same as piControl	1	30	Baseline for model-specific effective radiative forcing (ERF) calculations
piClim-anthro (amip)	As piClim-Control  except present-day anthropogenic forcing	All 2021, CO2 prescribed concentration	Same as piControl	Same as piControl	1	30	Quantify present-day total anthropogenic ERF
piClim-4xCO2 (amip)	As piClim-Control  except CO2 concentrations set to 4 times preindustrial	All 1850 except CO2 prescribed at 4 times preindustrial concentration	Same as piControl	Same as piControl	1	30	Quantify ERF of 4 × CO2

 

The CMIP Panel, WIP and relevant TTs are working on a dynamic format for the experiment specifications to ensure everyone can access the most up to date information rather than referring to a static paper going forwards. In the meantime, for forcings information and descriptions, we strongly recommend referring to the information/documentation found at https://wcrp-cmip.org/cmip-phases/cmip7/cmip7-forcing-datasets/ linking to the dataset overviews at https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/

[eleanororourke]

2025-10-14 update

All CMIP7 DECK historical forcings now available!

The CMIP Forcings Task Team would like to make you all aware that the full set of CMIP7 DECK historical forcings are now available and can be accessed here and below:

1. Anthropogenic short-lived climate forcer (SLCF) and CO₂ emissions
2. Open biomass burning emissions
3. Land use
4. Greenhouse gas concentrations
5. CO₂ isotopes
6. Stratospheric volcanic SO₂ emissions and aerosol optical properties
7. Ozone concentrations
8. Nitrogen deposition
9. Solar
10. AMIP sea-surface temperature and sea-ice boundary forcing
11. Aerosol optical properties/MACv2-SP
12. Population density

Please continue to ask questions and engage in discussions at the input4MIPs Github discussions and find all information relevant to CMIP7 Forcing datasets at https://wcrp-cmip.org/cmip-phases/cmip7/cmip7-forcing-datasets/

The TT is now working hard on delivering draft and final versions of the scenario forcings and will keep you regularly updated on the progress.

[eleanororourke]

2025-10-17 update

Request for feedback on Scenario Emission test datasets

The testing data for scenario emissions is now on ESGF and available at https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/anthropogenic-slcf-co2-emissions/#scenariomip.

In order to deliver the final product as soon as possible it is important that the team receives any feedback on the data within the next 1-2 weeks. A Github issue has been set up at #386 to signpost the data and gather feedback from you all.

Based on this feedback, the team will revise the data as much as needed to deliver a final product before the end of October. Feedback received after this time will not be integrated into the final product.

Contact: Jarmo Kikstra kikstra@iiasa.ac.at

CMIP7 stratospheric aerosol paper in open peer review

The first documentation paper from the volcanic emissions team documenting the optical property dataset is now open for peer review at https://egusphere.copernicus.org/preprints/2025/egusphere-2025-4990/ and the team welcomes community feedback.

[eleanororourke]

2025-10-29 update

CMIP7 DECK historical forcings

The full set of CMIP7 DECK historical forcings are now available and can be accessed here and below:

1. Anthropogenic short-lived climate forcer (SLCF) and CO₂ emissions
2. Open biomass burning emissions
3. Land use
4. Greenhouse gas concentrations
5. CO₂ isotopes
6. Stratospheric volcanic SO₂ emissions and aerosol optical properties
7. Ozone concentrations
8. Nitrogen deposition
9. Solar
10. AMIP sea-surface temperature and sea-ice boundary forcing
11. Aerosol optical properties/MACv2-SP
12. Population density

Please continue to ask questions and engage in discussions at the input4MIPs Github discussions and find all information relevant to CMIP7 Forcing datasets at https://wcrp-cmip.org/cmip-phases/cmip7/cmip7-forcing-datasets/

CMIP7 scenarios update and forcings development

Scenarios update
Responding to comments received during open community review of van Vuuren et al (2025) the ScenarioMIP Scientific Steering Committee and Advisory Group have updated some of the CMIP7 scenario names. Very Low Low Overshoot (VLLO) becomes Very Low (VL) and Very Low High Overshoot (VLHO) becomes Low to Negative (LN). A High-Low (HL) scenario that follows the high scenario until rapid mitigation begins around 2050 has also been added. An updated version of van Vuuren et al (2025) is expected to be available very soon.

CMIP7 Scenario forcing development
A number of preliminary scenario forcing datasets have already been made available via ESGF (see here for more information and links to the data) and are ready for testing by any interested modelling centres or data analysts. We encourage users to test the available datasets and provide feedback via input4MIPs Github discussions as soon as possible to refine the final scenario forcing development.

A small number of the scenario forcings (land use, ozone and nitrogen deposition) cannot produce all seven scenarios at the same time. Therefore, a scenario running order has been developed in close collaboration with ScenarioMIP and downstream activities such as ISIMIP, ISMIP7 and CORDEX, who require scenario data by July 2026 to facilitate their contribution to AR7. As outlined in Dunne et al. (2025) the CMIP Panel strongly encourages modelling centres to follow a running order, first running the H and VL scenario simulations, for which scenario forcings will be delivered by January 2026. Within the survey, accompanying this update, we are requesting feedback to support further guidance on the running order of the remaining scenarios up to 2100 and extensions out to 2300/2500.

Scenario	Scenario extension	Based on SSP
High (H)*	H-ext	SSP3
Very Low (VL)*	VL-ext	SSP1
High Low (HL)	HL-ext	SSP5
Medium (M)	M-ext	SSP2
Medium Low (ML)	ML-ext	SSP2
Low (L)	L-ext	SSP2
Low to Negative (LN)	LN-ext	SSP2

Note: H and VL will be made available first to allow the
chemistry-climate models to be initiated.

[eleanororourke]

@znicholls that is all the updates added pending one this week

[znichollscr]

2025-04-15 update

The table in this update isn't formatting correctly (specifically the bold isn't showing). Do we care?

[eleanororourke]

2026-02-12 update

CMIP7 forcings: modelling centres’ update

Date issued: 12 February 2026

This update provides the status of the delivery of the CMIP7 forcing datasets including an important notification on the historical ozone (v1.2) dataset. The homepage for CMIP7 Forcings datasets can be found here.

Request for feedback
Given the update on the error in v1.2 historical ozone dataset and scenario forcing data availability below, we would ask modelling centres to provide feedback by completing this form .

IMPORTANT: Updated dataset to address discontinuity between the PI control climatology and the historical ozone
A member of the community raised an issue with a discontinuity between the piControl climatology and the historical ozone. The full discussion is at #400

The ozone forcing providers have uploaded an updated version (v2.0) of the historical ozone concentrations to correct for the discontinuity in v1.2. The new historical ozone forcing v2.0, which can be found at this link, has an increased historical ozone burden of about 10% (primarily due to a vertical shift in the stratospheric ozone distribution).

The CMIP Panel co-chairs are recommending that, for modelling centres who rely on ozone as an external forcing, piControl, historical, and other relevant DECK (e.g., AMIP), simulations should be re-run with the v2.0 ozone if possible. For the piControl simulation, the 1850-1870 mean of v2.0 should be used (no specific piControl file will be produced for v2.0).
For those modellers who are not be able to repeat the piControl simulations, using the v1.2 PI climatology or the 1829-1849 20251025 v1.2 data is fine, since it is expected to be close to the 1850-1870 mean of v2.0.

However, it is preferable for a new historical simulation to be run with v2.0, if possible, and in advance of starting scenario simulations. If any modelling centres cannot re-run their historical simulations, they should contact the ozone forcing providers for guidance on use of future scenario ozone forcing files.

If any modelling centres run historical simulations with both v1.2 and v2.0 forcing, these simulations would be of interest to the Forcings Task Team.

Available CMIP7 scenario forcing datasets
To access the summary of CMIP7 ScenarioMIP datasets click here. The following scenario forcing datasets for the High (H) and Very Low (VL) scenarios are finalised and are now available:

(1) Anthropogenic short-lived climate forcer (SLCF) and CO2 emissions: IIASA-IAMC-vl-1-0-0; IIASA-IAMC-h-1-0-0 (DOI: 10.5281/zenodo.17981825.)

(2) Open biomass burning emissions: IIASA-IAMC-vl-1-0-0; IIASA-IAMC-h-1-0-0 (DOI: 10.5281/zenodo.17981825.)

(4) Greenhouse gas concentrations: CR-vl-1-0-0; CR-h-1-0-0 (DOI: No DOI provided.)

(6) Stratospheric volcanic SO2 emissions and aerosol optical properties: UOEXETER-ScenarioMIP-2-2-2 (No DOI provided)

PLEASE NOTE: Version 2.2.1 of the ScenarioMIP stratospheric aerosol optical properties has been updated to version 2.2.2 to fix an issue with the tropospheric mask. This issue resulted in a ~10% discrepancy between pre-industrial and ScenarioMIP stratospheric aerosol optical depth. Version 2.2.1 has been deprecated and version 2.2.2 (accessible here) should be used for ScenarioMIP runs. This only applies to ScenarioMIP files, stratospheric aerosol optical properties for DECK simulations are unchanged (version 2.2.1).

(9) Solar: SOLARIS-HEPPA-ScenarioMIP-4-6 (No DOI provided)

(12) Population density: PIK-vl-1-0-0; PIK-ln-1-0-0; PIK-l-1-0-0; PIK-ml-1-0-0; PIK-m-1-0-0; PIK-hl-1-0-0; PIK-h-1-0-0 (No DOI provided)

Please note that the van Vuuren et al. (2025) paper has been resubmitted with updates to two scenario names (VLLO becomes VL and VLHO becomes LN) plus a new scenario (HL). The updated table can be found at https://wcrp-cmip.org/mips/scenariomip/ and below. The updated or new scenarios are highlighted in bold.

Scenario	Scenario extension	Primary emission or temperature design criteria
High (H)	H-ext	Emissions as high as plausible consistent with climate policy rollback
High Low (HL)	HL-ext	High emissions until second half of the century, followed by rapid decline to net zero CO2 in 2100
Medium (M)	M-ext	Emissions consistent with current policies frozen as of 2025
Medium Low (ML)	ML-ext	Medium emissions until 2040 followed by gradual decline to net zero CO2 in 2100
Low (L)	L-ext	Emissions consistent with staying likely below 2C and not returning to 1.5C before end of the century
Very Low (VL) (Formerly Very Low Low Overshoot; VLLO)	VL-ext	Emissions consistent with limiting warming to 1.5C at the end of the century with overshoot as low as plausible
Low to Negative (LN) (Formerly Very Low High Overshoot; VLHO)	LN-ext	Emissions consistent with limiting warming to 1.5C at end of the century with high overshoot compared to the VL scenario.

Following the H and VL scenario forcings delivery, the CMIP Panel has decided that M and HL will be next in the running order.

Status of outstanding datasets
Land use
Preparation of the final H and VL land use scenario forcing datasets is nearing completion and we are anticipating publication by end of February.

Ozone concentrations and nitrogen deposition
Due to delays in the dependent datasets, the delivery of H and VL ozone and nitrogen deposition scenario datasets is now estimated for 10 March.

Aerosol optical properties/MACv2-SP
The expected date for publication for H and VL aerosol plumes scenarios is end of February.

Future extensions
The timeline for future extensions will be confirmed in the coming weeks following delivery of the land use data.

Impact of delays on downstream activities
During November 2025, modelling centres completed a survey indicating likely initiation and delivery of CMIP7 DECK and Assessment Fast Track data. Around 14 centres responded that they were intending to provide piControl, historical, and H and VL scenario data by 1 July 2026 to support downstream activities including ISIMIP, CORDEX and ISMIP7. ISIMIP has recently strongly emphasised their preference to receive historical simulation data as soon as possible and scenario data ideally by May/June at the latest to allow for their contribution to AR7.

Where to ask questions and raise issues about the forcing datasets
These discussions are all being captured on the input4MIPs GitHub. Issues related to any datasets can also be raised here https://github.com/PCMDI/input4MIPs_CVs/issues. Please go to these pages to read and engage in any discussions. The page has search functionality so you can find what you need.

[eleanororourke]

@znicholls have added today's update above and fixed the bolding in 2025-04-15 update

[github-actions]

No changes to the database between 'main' branch and 565950e

[github-actions]

No changes to the database between 'main' branch and f120409

[eleanororourke]

2026-02-16 update

Further to the update circulated on 12 February, there has been an iteration on the recommendation for piControl as follows:

Recommendation for pre-industrial control

The piControl forcing should come from files with the source ID FZJ-CMIP-ozone-1-2 data, (there are no specific piControl files available in the FZJ-CMIP-ozone-2-0 data). Note that this guidance differs from the email communication sent by the CMIP IPO on 12 February 2026.

For pre-industrial control, there are two options. The first is the monthly climatology file (frequency value of monC). This dataset averages over a longer simulation, essentially removing variability like the QBO. If you wish to use this forcing for your piControl, simply apply it on repeat.

The second is a transient file which has a time range equal to 182901-184912 in the filename. This file is found in the same directory as the historical forcing so please be careful to only use it for piControl and do not include it in historical forcing. This transient piControl forcing includes the QBO signal but uses average solar forcing and repeating 1850 emissions. If you wish to use this forcing for your piControl, simply apply it on repeat.

For full details on the ozone dataset please see Ozone concentrations - input4MIPs Controlled Vocabularies (CVs)

[github-actions]

No changes to the database between 'main' branch and 4e631db

[github-actions]

No changes to the database between 'main' branch and 2908684

[github-actions]

No changes to the database between 'main' branch and 6b1214c

[eleanororourke]

2026-02-24 update

The land use forcing data for the H and VL scenarios are now available – please see details at https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/land-use/#cmip7_1 and direct links below
UofMD-landState-vl-3-1
UofMD-landState-h-3-1

If you find an issue, please create an issue on GitHub so that the identification and resolution of this issue is publicly accessible.

Thank you to the dataset providers, Louise Chini and George Hurtt, for all their efforts.