Rising methane emissions from Finnish lakes due to climate warming and
increasing ice-free days
Abstract
Lakes account for about 10% of the boreal landscape and are responsible
for approximately 30% of biogenic methane emissions. However, its
quantification is still of large uncertainty under changing climate
conditions. Finland has the densest lake system in the world with most
lakes situated in the boreal zone. This study uses a large observational
dataset of lake methane concentrations to constrain its methane
emissions with an extant process-based lake biogeochemical model. We
found that the total current diffusive emission from Finnish lakes is
0.12±0.03 Tg CH yr and will increase by 26-59% by the end of this
century. We discovered that while warming lake water and sediment
temperature played an important role, the climate impact on ice-on
periods was a key indicator to the degree of emission increase in the
future. We concluded that these boreal lakes remain as a significant
methane source under warming climate in this century.