Sulphur shortage: Study highlights “potential resource crisis” as the world decarbonises

Sulphur obtained by mining in Kawah Ijen, a volcano in East Java, Indonesia: Research is urgently needed into low-impact methods of extracting sulphur from mineral deposits, say the authors of the study.

A projected shortage of sulphuric acid, a crucial chemical in our modern industrial society, could stifle green technology advancement and threaten global food security, according to a new study led by researchers from UCL.

The study, published in the Royal Geographical Society (with the Institute of British Geographers) journal The Geographical Journal, highlights that global demand for sulphuric acid is set to rise significantly from ‘246 to 400 million tonnes’ by 2040 – a result of more intensive agriculture and the world moving away from fossil fuels.

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.

A vital part of modern manufacturing, sulphuric acid is required for the production of phosphorus fertilisers that help feed the world, and for extracting rare metals from ores essential to the rapidly required green economy transition, like cobalt and nickel used in high-performance Li-ion batteries.

Currently, over 80% of the global sulphur supply is in the form of sulphur waste from the desulphurisation of crude oil and natural gas that reduces the sulphur 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 sulphur.

The study is seemingly the first to identify this major issue. The authors suggest that unless action is taken to reduce the need for this chemical, a massive increase in environmentally damaging mining will be required to fill the resulting resource demand.

Lead author, Professor Mark Maslin (UCL Geography), said: “Sulphur shortages have occurred before, but what makes this different is that the source of the element is shifting away from being a waste product of the fossil fuel industry.

“What we’re predicting is that as supplies of this cheap, plentiful, and easily accessible form of sulphur dry up, demand may be met by a massive increase in direct mining of elemental sulphur. This, by contrast, will be dirty, toxic, destructive, and expensive.

“Research is urgently needed to develop low-cost, low environmental impact methods of extracting large quantities of elemental sulphur from the abundant deposits of sulphate minerals in the Earth’s crust. The international community should consider supporting and regulating sulphur mining to minimise the impacts of the transition and also to avoid cheap unethical production from distorting the market.”

Study co-author Dr Simon Day (UCL Institute for Risk & Disaster Reduction) said: “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 sulphur supply, creating an issue with food production particularly in developing countries.”

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

The authors also explore several ways that demand for sulphur could be reduced as part of the transition to post-fossil fuel economies, including recycling phosphorus in wastewater for the fertiliser industry, by increasing the recycling of lithium batteries, or by using lower energy capacity/weight ratio batteries, as these require less sulphur for their production.

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 sulphur as a waste product from oil and gas desulphurisation will decrease as decarbonisation of the global economy is only just starting.

However, they conclude that by recognising the sulphur crisis now, national and international policies can be developed to manage future demand, increase resource recycling, and develop alternative cheap supplies