In the field of sustainable software engineering, the first principle focuses on carbon, specifically carbon dioxide. What is carbon dioxide? It's the most common greenhouse gas, consisting of one part carbon and two parts oxygen. Like all greenhouse gases, it acts as a blanket warming up the planet. According to Green Developer Relations Lead Asim Hussain, in the engineering space, the climate solution is building applications that are carbon efficient. See Principle 1: Carbon - Learn | Microsoft Docs for more information.