If you’re into carbon accounting, you’ve probably come across Scope 1, 2, and 3 emissions, which are used to determine a company’s carbon footprint and guide emissions reduction efforts… but have you heard of Scope 4 emissions? Most likely not yet. That's because Scope 4 emissions are in addition to the emissions that companies must track.  Although this concept is quite new, understanding it and knowing how to account for it is useful for companies and organizations that want to limit their emissions and meet their climate goals.  So, we will explain what Scope 4 emissions are, how they differ from other scopes, why it is important and beneficial for companies to measure and report them, along with the main challenges in calculating them. (Jennifer L)