A projected shortage of sulfuric acid could stifle green technology advancement and threaten global food security, according to a new study published today in the Royal Geographical Society (with the Institute of British Geographers) journal The Geographical Journal.

The study highlights that global demand for sulfuric acid is set to rise significantly from ‘246 to 400 million tonnes’ by 2040. The researchers estimate that this will result in a shortfall in annual supply of between 100 and 320 million tonnes – between 40 and 130% of current supply – depending on how quickly decarbonisation occurs.

Currently, over 80% of the global sulfur supply is in the form of sulfur waste from the desulfurisation of crude oil and natural gas that reduces the sulfur dioxide gas emissions that cause acid rain. However, decarbonisation of the global economy to deal with climate change will significantly reduce the production of fossil fuels – and subsequently the supply of sulfur.

Study lead author, Professor Mark Maslin (UCL Geography), said: “What we’re predicting is that as supplies of this cheap, plentiful, and easily accessible form of sulfur dry up, demand may be met by a massive increase in direct mining of elemental sulfur. This, by contrast, will be dirty, toxic, destructive, and expensive.

“Research is needed to develop low-cost, low environmental impact methods of extracting large quantities of elemental sulfur from the abundant deposits of sulfate minerals in the Earth’s crust.”

“Our concern is that the dwindling supply could lead to a transition period when green tech outbids the fertiliser industry for the limited more expensive sulfur supply," commented Dr Simon Day (UCL Institute for Risk and Disaster Reduction).

To determine their findings, the researchers estimated three sulfuric acid demand scenarios from 2021 to 2040, based on historic and forecast demand, with annual growth rates ranging from 1.8% to 2.4%.

In addition, they prompt crucial questions about whether it would make economic sense to invest in alternative production methods, given it is not currently possible to predict how quickly the supply of sulfur as a waste product from oil and gas desulfurisation will decrease as decarbonisation of the global economy is only just starting.