Metals are key nutrients in the industrial ecosystem, and it is thus unsurprising that they play a central role in industrial ecology. Steel in particular, with its excellent structural properties and relatively low cost, has come to be a dominant force in many sectors, such as construction, transportation, machinery, and packaging. Inexpensive mass production of steel began with the invention of the Bessemer process in 1855. At the turn of the century, global annual production was already 28 million metric tons (Mt). At the end of the millennium, global annual production had reached 850 Mt, and industry experts were wondering whether global demand had finally reached its peak. Not quite. In less then 20 years global output more than doubled to 1,800 Mt in 2018. The steadily decreasing emission intensity of steel production and the high recycling rate of steel scrap are no environmental match for the relentless growth in total output. No wonder steel is an important indicator of environmental progress or the lack thereof.


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