Lessons learned from developing green software

Technology brings exciting opportunities to improve our interactions with the natural surroundings. However, that same technological development might also negatively impact the environment. Every new technology has a carbon footprint, whether from its construction or operation. And most technological developments require software systems, and more recently AI-based software systems. For these software systems to positively impact our environment, they need to be developed and operated with sustainability in mind, also called 'green' in the discipline of software engineering. This chapter explores various dimensions of sustainability in software system development, drawing on existing software quality frameworks. We highlight green software best practices for development and knowledge transfer. We examine AI-based software systems, emphasising the importance of energy efficiency and carbon impact in the next generation of intelligent systems. This entails considering decisions at different stages of the AI lifecycle, ranging from underlying design choices in training pipelines to selecting optimal hardware for training and serving models. This chapter presents the intersection of green software, sustainable software engineering, and green AI as of major importance for future innovation. By prioritising sustainability in software development and AI, we can foster a more sustainable and eco-friendly future, with the potential to reduce energy consumption and mitigate the environmental impact of technology.