Earth's global Ag, Al, Cr, Cu, Fe, Ni, Pb, and Zn cycles

The stocks and flows of the global silver, aluminum, chromium, copper, iron, nickel, lead, and zinc cycles quantify over 98% of the total mass of metal mobilized by human activity at the turn of the 21st century. Iron and aluminum, representing >95% by mass of all metals mined, are for the first time assessed for global anthropogenic emissions to air, water, and land. Anthropogenic activity has significantly perturbed Earth's natural biogeochemical cycles, attested by the “grand nutrient” cycles of carbon, nitrogen, phosphorous, and sulfur and further revealed here by the “anthrobiogeochemical” cycles of metals. We demonstrate that humans today mobilize about half the metal mass of these global elemental metal cycles.