Global trade moves far more than just goods—it also unintentionally transports plants and animals to new places, where they can disrupt ecosystems and threaten native wildlife. This chapter explains how these accidental introductions happen and how they have grown over nearly 150 years of increasing global connection. By combining worldwide trade statistics with records of where alien species first appear, the study shows how the movement of commodities can lead to new biological invasions. It also measures how these invasions affect native species, especially those already vulnerable to extinction. The result is a set of impact factors that reveal how each kilogram of traded goods contributes to biodiversity loss.