Climate-induced Arctic-boreal peatland fire and carbon loss in the 21st century.

Boreal peatlands are increasingly vulnerable to wildfires as climate change continues accelerating. Fires consume substantial quantities of organic soils and rapidly transfer large stocks of terrestrial carbon to the atmosphere. Herein, we quantify the minimum environmental temperature from -45 °C to 45 °C that allows the moist peat to smolder, as the fire threshold of peatlands. We then apply a typical vertical soil temperature profile to estimate the future depth of burn and carbon emissions from boreal peatland fires under the impact of global warming. If the boreal region continues warming at a rate of 0.44 °C/decade, we estimate the carbon loss from the boreal peat fires on a warmer soil layer may increase from 143 Mt. in 2015 to 544 Mt. in 2100 and reach a total of 28 Gt in the 21st century. If the global human efforts successfully reduce the boreal warming rate to 0.3 °C/decade, the peat fire carbon loss would drop by 21% to 22 Gt in the 21st century. This work helps understand the vulnerability of boreal peatland to more frequent and severer wildfires driven by global warming and estimate climate-induced carbon emissions from boreal peatland fires in the 21st century.