The article discusses different ways to measure the water footprint, or how much water is used or affected by human activities. It points out that there are two main methods used: looking at the amount of water used directly and considering the environmental impacts of water use. The article emphasizes that one type of water footprint called "scarcity water footprint" is actually a specific form of the impact-based approach. By clarifying these distinctions, the article highlights that there's a need to correctly distinguish between the two methods to prevent confusion and misinformation.