Acidification also counts when the environmental impact of metals is assessed. Metal production has a climate component, but it can also contribute to acidification of soils and ecosystems. That makes a broader environmental assessment necessary.
The Binas contribution shows that material impact consists of multiple indicators. CO2 is important, but it is not the only relevant effect. By placing acidification alongside climate impact, scarcity and recycling, the table gives a fuller picture of metals and helps students understand why one material choice can create several environmental effects at once.