Open AccessPermafrost thaw driven changes in hydrology and vegetation cover increase trace gas emissions and climate forcing in Stordalen Mire from 1970 to 2014
Author(s) -
Ruth K. Varner,
Patrick Crill,
Steve Frolking,
C. K. McCalley,
S. A. Burke,
Jeffrey P. Chanton,
M. E. Holmes,
AUTHOR_ID,
S. R. Saleska,
M. W. Palace
Publication year - 2021
Publication title -
philosophical transactions - royal society. mathematical, physical and engineering sciences/philosophical transactions - royal society. mathematical, physical and engineering sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.074
H-Index - 169
eISSN - 1471-2962
pISSN - 1364-503X
DOI - 10.1098/rsta.2021.0022
Subject(s) - mire , permafrost , environmental science , radiative forcing , sphagnum , peat , climate change , hydrology (agriculture) , global warming , greenhouse gas , forcing (mathematics) , trace gas , ecosystem , wetland , vegetation (pathology) , physical geography , climatology , atmospheric sciences , ecology , oceanography , geology , geography , medicine , geotechnical engineering , pathology , biology
Permafrost thaw increases active layer thickness, changes landscape hydrology and influences vegetation species composition. These changes alter belowground microbial and geochemical processes, affecting production, consumption and net emission rates of climate forcing trace gases. Net carbon dioxide (CO2 ) and methane (CH4 ) fluxes determine the radiative forcing contribution from these climate-sensitive ecosystems. Permafrost peatlands may be a mosaic of dry frozen hummocks, semi-thawed or perched sphagnum dominated areas, wet permafrost-free sedge dominated sites and open water ponds. We revisited estimates of climate forcing made for 1970 and 2000 for Stordalen Mire in northern Sweden and found the trend of increasing forcing continued into 2014. The Mire continued to transition from dry permafrost to sedge and open water areas, increasing by 100% and 35%, respectively, over the 45-year period, causing the net radiative forcing of Stordalen Mire to shift from negative to positive. This trend is driven by transitioning vegetation community composition, improved estimates of annual CO2 and CH4 exchange and a 22% increase in the IPCC's 100-year global warming potential (GWP_100) value for CH4 . These results indicate that discontinuous permafrost ecosystems, while still remaining a net overall sink of C, can become a positive feedback to climate change on decadal timescales.This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’.