Nuno Saavedra, Alexandra Mendes, and João F. Ferreira, researchers from the University of Porto in Portugal, have recently published a study in the journal *Environmental Software Systems* that sheds light on the environmental impact of Continuous Integration/Continuous Deployment (CI/CD) pipelines, specifically focusing on GitHub Actions.
CI/CD pipelines are integral to modern software development, automating the process of building, testing, and deploying code. However, their environmental impact, particularly in terms of carbon and water footprints, has largely been overlooked. As cloud computing’s environmental footprint grows, understanding the carbon and water footprints (CWF) of CI/CD services has become increasingly important.
The researchers analyzed over 2.2 million workflow runs from more than 18,000 repositories using GitHub Actions, the largest dataset of its kind. They built upon the methodology from the Cloud Carbon Footprint framework to estimate the carbon and water footprints of these workflows. Their findings reveal a substantial environmental impact. In 2024, the carbon footprint of GitHub Actions is estimated to range from 150.5 to 994.9 metric tons of CO2 equivalent (MTCO2e), with a most likely scenario of 456.9 MTCO2e. The water footprint ranges from 1,989.6 to 37,664.5 kiloliters, with a most likely scenario of 5,738.2 kiloliters.
To put these numbers into perspective, the most likely carbon footprint scenario is equivalent to the carbon captured by 7,615 urban trees in a year. The water footprint is comparable to the water consumed by an average American family over 5,053 years.
The study also provides strategies to mitigate this impact, primarily by reducing wasted computational resources. Key recommendations include deploying runners in regions with low environmental impact energy production, such as France and the United Kingdom, implementing stricter deactivation policies for scheduled runs, aligning their execution with periods of more environmentally favorable energy mix, and reducing the size of repositories.
For the energy sector, this research highlights the importance of considering the environmental impact of cloud computing services. As more industries, including energy, increasingly rely on cloud-based services for data analysis, monitoring, and management, understanding and mitigating the environmental impact of these services becomes crucial. The recommendations provided in the study can serve as a guide for energy companies to reduce the carbon and water footprints of their cloud computing activities.
The research was published in the journal *Environmental Software Systems*, providing a valuable contribution to the growing body of knowledge on the environmental impact of digital technologies.
This article is based on research available at arXiv.