We are excited to announce the release of OSCAR v4! OSCAR is an open-source, reduced-complexity Earth system model (ESM) designed to probabilistically emulate the coupled climate–carbon–chemistry system. This latest version introduces enhanced numerical stability, modular submodels, and recalibration using AR6, CMIP6, and TRENDY datasets, among other things.
Warning
This package is currently in Beta (v4-beta0). We are actively refining features and documentation.
We expect a stable v4.0 by the end of 2026.
Action Required: Expect frequent updates in the coming months; please keep your package up to date.
Support & Feedback:
- Technical Issues: For bug reports or feature suggestions, please open an issue on the Issue Board.
- Scientific Collaboration: For research inquiries, contact the OSCAR model team at OSCAR_model@iiasa.ac.at.
OSCAR v4 bridges comprehensive ESMs and simpler reduced-complexity approaches, providing rapid, policy-relevant, probabilistic climate projections.
Key Improvements:
- User-oriented functionalities.
- Modularized code for independent submodel execution.
- Robust Monte Carlo & Latin hypercube sampling for improved probabilistic ensembles.
- Benchmarked via the Reduced Complexity Model Intercomparison Project (RCMIP) phase 3.
References:
v4.0 | Gasser et al., in preparation.
v3.1 | Gasser, T., L. Crepin, Y. Quilcaille, R. A. Houghton, P. Ciais & M. Obersteiner. "Historical CO2 emissions from land-use and land-cover change and their uncertainty." Biogeosciences 17: 4075–4101 (2020). doi:10.5194/bg-17-4075-2020
v2.2 | Gasser, T., P. Ciais, O. Boucher, Y. Quilcaille, M. Tortora, L. Bopp & D. Hauglustaine. "The compact Earth system model OSCAR v2.2: description and first results." Geoscientific Model Development 10: 271-319 (2017). doi:10.5194/gmd-10-271-2017
OSCAR can be installed via pip or uv. We recommend uv for a faster and cleaner environment setup.
Requires uv.
# Create a virtual environment and install OSCAR
uv venv
uv pip install git+https://github.com/iiasa/OSCAR.git
# Run the verification model
uv run oscar run# Install directly from GitHub
pip install git+https://github.com/iiasa/OSCAR.git
# Run the verification model
oscar runOSCAR is self-documenting and supports multiple run levels.
You can both inspect a mode and execute it from the Terminal or Python.
| Mode | Purpose | Inspect (Terminal) | Inspect (Python) | Run (Terminal) | Run (Python) | Status |
|---|---|---|---|---|---|---|
| General | Package overview & guidance | oscar |
oscar.info() |
— | — | ✅ Available |
| Standard | Instant verification simulation | oscar info standard |
oscar.info("standard") |
oscar run |
oscar.run() |
✅ Available |
| Configured | Official scenario library runs | oscar info configured |
oscar.info("configured") |
oscar run -m configured |
oscar.run(mode="configured") |
✅ Available |
| Customized | User-defined research workflows | — | oscar.info("customized") |
— | oscar.run(mode="customized") |
🚧 In Development |
| Advanced | Core model development | — | — | — | oscar.run(mode="advanced") |
🚧 In Development |
Note: Scientific modes (Configured and above) require access to a large data library.
The model will guide you through a one-time directory initialization on first use.
Run the 2024-2100 verification simulation with a single command:
oscar runRun a specific CMIP7 regional projection for multiple SSP scenarios:
import oscar
# Run official scenarios for the 5 RCP regions
oscar.run(
mode="configured",
scenario=["scen7-VL","scen7-H"],
region="RCP_5reg"
)Run user defined scenarios
Preparation:
-
Download Templates: Look for
setting_template.yaml -
Create Project Folder :
oscar.create_project('my-project')- (optional) put user forcing in this project folder (if empty, model will run with baseline scenarios)
- modify the setting file:
setting_my-experiment.yaml
-
Run Simulation with:
import oscar
# Run user-defined scenarios
oscar.run(
mode="customized",
project='my-project',
experiment='my-experiment'
)Note: run oscar.info('customized') for detailed information.
To remove OSCAR and its associated files:
| Target | Command / Action |
|---|---|
| Package (uv) | Delete the .venv folder and the project directory. |
| Package (pip) | Run pip uninstall oscar. |
| Data Library | Manually delete the data folder you initialized during setup. |