# ESMValTool

> ESMValTool: A community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP

**Wikidata**: [Q120938869](https://www.wikidata.org/wiki/Q120938869)  
**Source**: https://4ort.xyz/entity/esmvaltool

## Summary
ESMValTool is a free, community-developed software tool designed for the routine evaluation of Earth system models participating in the Coupled Model Intercomparison Project (CMIP). It provides users with diagnostics and performance metrics to assess model outputs, distributed under the Apache Software License 2.0.

## Key Facts
- **License:** Distributed as free software under the Apache Software License 2.0.
- **Primary Function:** Serves as a community diagnostic and performance metrics tool for Earth system models in CMIP.
- **Source Code Repository:** Hosted on GitHub at `https://github.com/ESMValGroup/ESMValTool`.
- **Website:** Official documentation and information available at `https://esmvaltool.org/`.
- **Version History (Selected):** Version 2.0.0 was released on August 3, 2020; Version 2.8.0 was released on March 28, 2023.
- **Software Class:** Classified as free software, allowing users to run, study, change, and distribute it.
- **Download Availability:** Releases are accessible via the GitHub releases page.

## FAQs
### Q: What is the primary purpose of ESMValTool?
A: ESMValTool is designed for the routine evaluation of Earth system models used in CMIP. It provides a standardized set of diagnostics and performance metrics for analyzing model behavior.

### Q: Is ESMValTool free to use?
A: Yes, ESMValTool is free software distributed under the Apache Software License 2.0, which permits users to freely use, modify, and distribute the software.

### Q: Where can the source code for ESMValTool be found?
A: The source code is maintained in a public repository on GitHub under the ESMValGroup organization.

## Why It Matters
ESMValTool plays a critical role in the field of climate science by standardizing the evaluation process for complex Earth system models. As these models are fundamental to understanding climate change and variability (specifically within the framework of CMIP), having a community-maintained tool ensures that evaluations are reproducible, comprehensive, and quasi-operational.

By offering an extended set of large-scale diagnostics, the tool bridges the gap between raw model output and actionable scientific insight. Its open-source nature (Apache 2.0) fosters transparency and collaboration, allowing a diverse community of scientists to contribute to the improvement of climate modeling techniques. The frequent release cycle—spanning versions 2.0.0 in 2020 to 2.8.0 in 2023—demonstrates an active, maintained effort to keep pace with the evolving needs of climate researchers.

## Notable For
- **Community Development:** It is explicitly a "community diagnostic" tool, relying on contributions from a broad user base rather than a single closed entity.
- **CMIP Focus:** It is specialized for the Coupled Model Intercomparison Project (CMIP), which is the standard framework for climate model intercomparison.
- **Open Licensing:** Unlike proprietary alternatives, it uses the permissive Apache Software License 2.0.
- **Active Maintenance:** The project maintains a rapid release schedule, with eight minor versions (2.0.0 to 2.8.0) released between August 2020 and March 2023.

## Body

### Software Classification and Licensing
ESMValTool is classified as free software. It is distributed under the terms of the **Apache Software License 2.0**. This classification ensures that users have the legal freedom to run, study, change, and distribute the software and any modified versions of it. The project is described in academic sources as "a community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP."

### Version History and Development
The tool has undergone significant development, particularly within the version 2.x lifecycle. The project utilizes a semantic versioning system. According to structured data from Wikidata and GitHub, the following key releases have been recorded:

- **v2.0.0:** Released on August 3, 2020. This version is associated with the publication "ESMValTool v2.0 – Extended set of large-scale diagnostics for quasi-operational and comprehensive evaluation of Earth system models in CMIP."
- **v2.1.0:** Released on October 26, 2020.
- **v2.2.0:** Released on February 25, 2021.
- **v2.3.0:** Released on July 27, 2021.
- **v2.4.0:** Released on November 9, 2021.
- **v2.5.0:** Released on March 15, 2022.
- **v2.6.0:** Released on July 25, 2022.
- **v2.7.0:** Released on October 28, 2022.
- **v2.8.0:** Released on March 28, 2023.

### Technical Infrastructure
The technical home for ESMValTool is hosted on GitHub under the group **ESMValGroup**. The official website serves as the portal for the tool, while the repository provides the download URL for all releases. The project facilitates the evaluation of Earth system models by providing pre-processing and diagnostic capabilities tailored to the CMIP context. The existence of version 1.0 is noted in the source descriptions ("ESMValTool (v1.0)"), indicating a long-standing history of development prior to the extensive v2.x expansion.

## References

1. [Release 2.0.0. 2020](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.0.0)
2. [Release 2.1.0. 2020](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.1.0)
3. [Release 2.1.1. 2020](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.1.1)
4. [Release 2.2.0. 2021](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.2.0)
5. [Release 2.3.0. 2021](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.3.0)
6. [Release 2.4.0. 2021](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.4.0)
7. [Release 2.5.0. 2022](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.5.0)
8. [Release 2.6.0. 2022](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.6.0)
9. [Release 2.7.0. 2022](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.7.0)
10. [Release 2.8.0. 2023](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.8.0)
11. [Release 2.9.0. 2023](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.9.0)
12. [Release 2.10.0. 2023](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.10.0)
13. [Release 2.11.0. 2024](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.11.0)
14. [Release 2.12.0. 2025](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.12.0)
15. [Release 2.13.0. 2025](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.13.0)
16. [Release 2.14.0. 2026](https://github.com/ESMValGroup/ESMValTool/releases/tag/v2.14.0)
17. [Source](https://api.github.com/repos/ESMValGroup/ESMValTool)