Peatlands in the northern hemisphere store vast quantities of Earth’s soil carbon, largely thanks to the cold and wet climate which limits decomposition of organic matter. However, these fragile wetland systems are rapidly changing in response to warming temperatures, changing precipitation patterns, permafrost thaw, and drainage for agriculture or mining. All of which act to make peatlands either drier or wetter. In turn altering carbon storage and greenhouse gas emissions. To understand the future fate of Earth’s terrestrial carbon stores, we must understand how peatlands will respond to these stressors.

However, not all peatlands are the same. Local variations in hydrology, geology and geochemistry can make the degradation of some peatlands complex to predict and challenging to mitigate. For example, in areas rich in iron, enhanced waterlogging (such as is promoted by permafrost thaw) can release large quantities of previously mineral-associated carbon. On the other hand, drainage of iron-rich peatlands can release sulfuric acid, iron and toxic metals which make them complicated to restore. Using a combination of insights from mineralogy, geochemistry and microbiology at peatlands across the northern hemisphere; I will discuss the role of iron in shaping peatland degradation responses and the strategies needed to protect iron-rich peatlands in the future.