Rising temperatures will lead to the accelerated weathering of rocks in the Canadian Arctic, causing more CO2 to be released into the atmosphere, University of Oxford researchers have found.

In the Arctic, where surface air temperatures are warming nearly four times faster than the global average, understanding the potential contribution of atmospheric CO2 from weathering is crucial, the researchers said.

Certain minerals and rocks react with oxygen in the atmosphere, releasing CO2 through a series of chemical reactions.

The weathering of sulphide minerals, such as 'fool's gold', produces acid, which causes CO2 to be released from other nearby rock minerals.

In Arctic permafrost, these minerals are being exposed as the ground thaws due to rising temperatures, potentially accelerating climate change.

However, until now, it was largely unknown how this reaction would respond to temperature change and how much extra CO2 could be released.

The researchers used records of sulphate concentration and temperature from 23 sites across the Mackenzie River Basin, the largest river system in Canada, to examine the sensitivity of the weathering process to rising temperatures.

Dr Ella Walsh, lead author from the Department of Earth Sciences at the University of Oxford, said: "We see dramatic increases in sulphide oxidation across the Mackenzie River Basin with even moderate warming.

"Until now, the temperature sensitivity of CO2 release from sulphide rocks and its main drivers were unknown over large areas and timescales."

Sulphate, like CO2, is a product of sulphide weathering, and can be used to trace how fast this process occurs.

The results showed across the catchment, sulphate concentrations rose rapidly with temperature.

From 1960 to 2020, sulphide weathering increased by 45 per cent as temperatures increased by 2.3°C.

This indicates, the researchers said, CO2 released by weathering could trigger a positive feedback loop, accelerating warming in Arctic regions.

The researchers predicted CO2 released from the Mackenzie River Basin could double to three billion kg/year by 2100 under a moderate emission scenario.

This would be equivalent to about half the total annual emissions from Canada’s domestic aviation sector for a typical year.

Professor Bob Hilton, co-author from the Department of Earth Sciences at the University of Oxford, said: "Future warming across vast Arctic landscapes could further increase sulphide oxidation rates and affect regional carbon cycle budgets.

"Now that we have found this out, we are working to understand how these reactions might be slowed down, and it seems that peatland formation could help to lower the sulphide oxidation process."

According to the researchers, the study highlights the value of considering sulphide weathering in large scale emission models, which are extremely useful for making predictions of climate change.