Sulphur shortage: a potential resource crisis looms as the world decarbonizes

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

The study, published in the Royal Geographical Society journal, indicates that global demand for sulphuric acid is set to rise significantly, to 400 million tonnes from the current 246 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 100 to 320 million tonnes, between 40 and 130 per cent of current supply, depending on how quickly decarbonization occurs.

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

Currently, more than 80 per cent of the global sulphur supply is in the form of waste from the desulphurization of crude oil and natural gas that reduces sulphur dioxide gas emissions that cause acid rain. However, decarbonization of the global economy to deal with climate change will significantly reduce the production of fossil fuels and subsequently the supply of sulphur.

This study, led by researchers at University College London, is 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.

“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,” said professor Mark Maslin, the study lead author.

“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 sulfate minerals in the Earth’s crust. The international community should consider supporting and regulating sulphur mining to minimize the impacts of the transition and also to avoid cheap unethical production from distorting the market.”

Added study co-author Simon Day of the UCL Institute for Risk and Disaster Reduction, “our concern is that the dwindling supply could lead to a transition period when green tech outbids the fertilizer 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 per cent.

The authors also explored 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 fertilizer industry, increasing the recycling of lithium batteries, or by using lower energy capacity/weight ratio batteries, because 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 possible to predict how quickly the supply of sulphur as a waste product from oil and gas desulphurization will decrease, given that decarbonization of the global economy is just starting.

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