Disentangling the hidden methane consumption in a warmer Arctic

The Arctic terrestrial methane debate is strongly biased by results from carbon-rich wetlands, which are methane-emission hotspots. Less attention has been given to the carbon-poor mineral soils, cover almost 87% of the Arctic.

The terrestrial methane budget is determined by two contrasting processes, production and consumption, both occurring within the soil.

In previous work we have shown a consistent increase (23-27%) in methane consumption when ecosystems have adapted to a future climate (year 2050-2080).

In this proposal, we will challenge the emissions-dominated view of the Arctic, and test if our results can be generalized to a circumpolar context.With global warming, Arctic plant communities respond rapidly, leading to taller plants, increased biomass, and changed composition.

These changes will lead to increased oxygen availability in surface soils (e.g. increased evapotranspiration), a process critical for the methane budget.

Methane is produced during anoxic conditions in water-saturated soils, while the aerated surface soil is occupied by methane-consuming bacteria, strongly reducing emissions or even absorbing atmospheric methane, processes often hidden in measurements.We hypothesize that changes in plant communities and climate conditions will significantly increase the methane consumption rates, increasing the Arctic sink strength.

This represents an important negative climate feedback, potentially giving us the time needed to reach a climate neutral lifestyle.