Rapid carbon loss from warming peatlands

Scientists have demonstrated a direct relationship between climate warming and carbon loss in a peatland ecosystem. Their study provides a glimpse of potential futures where significant stores of carbon in peat bogs could be released into the atmosphere as greenhouse gases.

Peatlands currently cover around 3% of Earth’s landmass and hold at least a third of global soil carbon – more carbon than is stored in the world’s forests.

Peat bogs are particularly good at locking away carbon because of the cold, wet, acidic conditions that preserve meters-deep layers of ancient plant matter.

Scientists have taken a keen interest in these enormous carbon reserves, questioning how much and how quickly the hotter, drier conditions in a peatland bog can trigger microbial processes that release carbon in the form of carbon dioxide and methane into the air, furthering the warming cycle as the gases trap heat in the atmosphere.

The US Department of Energy’s Spruce and Peatland Responses Under Changing Environments, or SPRUCE project, studies a unique whole ecosystem manipulation experiment in the forests of northern Minnesota, explains a statement.

SPRUCE uses a series of enclosures to expose large peatland plots to five different temperatures, with the hottest of the chambers experiencing an increase of about 16 degrees Fahrenheit above and deep belowground. Half the enclosures also received elevated levels of carbon dioxide.

This futuristic experiment allows scientists to measure the effects of conditions this ecosystem has never experienced before, providing a glimpse of potential future climates.

The study found that in just three years, all warmed bog plots turned from carbon accumulators into carbon emitters – marking the first time whole-ecosystem plots have been used to document such changes.

Warmer temperatures directly translated into greater carbon emissions, with the warmest of the experimentally heated plots emitting the most carbon dioxide and methane.

The SPRUCE data will inform a new wetland model for potential use in DOE’s Energy Exascale Earth System Model project, which uses high-performance computing to simulate and predict environmental changes important to the energy sector.

Photo credit: MIT

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