Without sulfur in the form of sulfuric acid, industries would struggle to produce the phosphorus fertilisers that raise farm yields or extract the essential metals used in everything from solar panels to electric car batteries.
Yet a problem looms, which has gone largely unnoticed. More than 80% of the global sulfur supply is a waste product, extracted from fossil fuels like oil and natural gas (which typically contain between 1% and 3% sulfur by weight) to reduce emissions of sulfur dioxide, the gas that causes acid rain.
