Unveiling the impact of soil methane sink on atmospheric methane concentrations in 2020

In 2020, anthropogenic methane (CH4) emissions decreased due to COVID-19
containment policies, but there was a substantial increase in the
concentration of atmospheric CH4. Previous research suggested that this
abnormal increase was linked to higher wetland CH4 emissions and a
decrease in the atmospheric CH4 sink. However, the impact of changes in
the soil CH4 sink remained unknown. To address this, we utilized a
process-based model to quantify the alterations in the soil CH4 sink of
terrestrial ecosystems between 2019 and 2020. By implementing the model
with various datasets, we consistently observed an increase in the global
soil CH4 sink, reaching up to 0.35 ± 0.06 Tg in 2020 compared to 2019.
This increase was primarily attributed to warmer soil temperatures in
northern high latitudes. These findings emphasize the importance of
considering the CH4 sink in terrestrial ecosystems, as neglecting it can
lead to an underestimation of both emission increases and reductions in
atmospheric CH4 sink capacity. Furthermore, they highlight the potential
role of increased soil warmth in terrestrial ecosystems in slowing the
growth of CH4 concentrations in the atmosphere.