Ecosystem and soil respiration radiocarbon detects old carbon release as a fingerprint of warming and permafrost destabilization with climate change

The permafrost region has accumulated organic carbon in cold and waterlogged soils over thousands of years and now contains three times as much carbon as the atmosphere. Global warming is degrading permafrost with the potential to accelerate climate change as increased microbial decomposition releases soil carbon as greenhouse gases. A 19-year time series of soil and ecosystem respiration radiocarbon from Alaska provides long-term insight into changing permafrost soil carbon dynamics in a warmer world. Nine per cent of ecosystem respiration and 23% of soil respiration observations had radiocarbon values more than 50‰ lower than the atmospheric value. Furthermore, the overall trend of ecosystem and soil respiration radiocarbon values through time decreased more than atmospheric radiocarbon values did, indicating that old carbon degradation was enhanced. Boosted regression tree analyses showed that temperature and moisture environmental variables had the largest relative influence on lower radiocarbon values. This suggested that old carbon degradation was controlled by warming/permafrost thaw and soil drying together, as waterlogged soil conditions could protect soil carbon from microbial decomposition even when thawed. Overall, changing conditions increasingly favoured the release of old carbon, which is a definitive fingerprint of an accelerating feedback to climate change as a consequence of warming and permafrost destabilization. This article is part of the Theo Murphy meeting issue ‘Radiocarbon in the Anthropocene’.

[1]  E. Schuur,et al.  Organic‐Matter Accumulation and Degradation in Holocene Permafrost Deposits Along a Central Alaska Hillslope , 2023, Journal of Geophysical Research: Biogeosciences.

[2]  Intergovernmental Panel on Climate Change Climate Change 2021 – The Physical Science Basis , 2023 .

[3]  A. Richardson,et al.  ATMOSPHERIC RADIOCARBON FOR THE PERIOD 1910–2021 RECORDED BY ANNUAL PLANTS , 2023, Radiocarbon.

[4]  C. Czimczik,et al.  Reductions in California's Urban Fossil Fuel CO2 Emissions During the COVID‐19 Pandemic , 2022, AGU Advances.

[5]  Julia E. M. Stuart,et al.  Evidence for older carbon loss with lowered water tables and changing plant functional groups in peatlands , 2022, Global change biology.

[6]  D. Lawrence,et al.  Permafrost and Climate Change: Carbon Cycle Feedbacks From the Warming Arctic , 2022, Annual Review of Environment and Resources.

[7]  T. Lenton,et al.  Exceeding 1.5°C global warming could trigger multiple climate tipping points , 2022, Science.

[8]  T. Vihma,et al.  The Arctic has warmed nearly four times faster than the globe since 1979 , 2022, Communications Earth & Environment.

[9]  C. Czimczik,et al.  Closing the Winter Gap—Year‐Round Measurements of Soil CO2 Emission Sources in Arctic Tundra , 2022, Geophysical Research Letters.

[10]  B. Kromer,et al.  RADIOCARBON IN GLOBAL TROPOSPHERIC CARBON DIOXIDE , 2021, Radiocarbon.

[11]  E. Bard,et al.  Radiocarbon: A key tracer for studying Earth’s dynamo, climate system, carbon cycle, and Sun , 2021, Science.

[12]  M. Mauritz,et al.  Experimental Soil Warming and Permafrost Thaw Increase CH4 Emissions in an Upland Tundra Ecosystem , 2021, Journal of Geophysical Research: Biogeosciences.

[13]  R. Striegl,et al.  Complex Vulnerabilities of the Water and Aquatic Carbon Cycles to Permafrost Thaw , 2021, Frontiers in Climate.

[14]  M. Mauritz,et al.  Investigating Thaw and Plant Productivity Constraints on Old Soil Carbon Respiration From Permafrost , 2021, Journal of Geophysical Research: Biogeosciences.

[15]  M. Mauritz,et al.  Tundra Underlain By Thawing Permafrost Persistently Emits Carbon to the Atmosphere Over 15 Years of Measurements , 2021, Journal of Geophysical Research: Biogeosciences.

[16]  M. Mauritz,et al.  Lower soil moisture and deep soil temperatures in thermokarst features increase old soil carbon loss after 10 years of experimental permafrost warming , 2020, Global change biology.

[17]  M. Lupascu,et al.  Assessing the Potential for Mobilization of Old Soil Carbon After Permafrost Thaw: A Synthesis of 14C Measurements From the Northern Permafrost Region , 2020, Global Biogeochemical Cycles.

[18]  M. Mauritz,et al.  Carbon Thaw Rate Doubles When Accounting for Subsidence in a Permafrost Warming Experiment , 2020, Journal of Geophysical Research: Biogeosciences.

[19]  D. Lawrence,et al.  Soil moisture and hydrology projections of the permafrost region – a model intercomparison , 2020 .

[20]  Andreas Kääb,et al.  Northern Hemisphere permafrost map based on TTOP modelling for 2000–2016 at 1 km2 scale , 2019, Earth-Science Reviews.

[21]  E. Schuur,et al.  Millennial-scale carbon accumulation and molecular transformation in a permafrost core from Interior Alaska , 2019, Geochimica et Cosmochimica Acta.

[22]  M. Heimann,et al.  Drainage enhances modern soil carbon contribution but reduces old soil carbon contribution to ecosystem respiration in tundra ecosystems , 2019, Global change biology.

[23]  M. Phillips,et al.  Permafrost is warming at a global scale , 2019, Nature Communications.

[24]  Michelle C. Mack,et al.  Ecological Response to Permafrost Thaw and Consequences for Local and Global Ecosystem Services , 2018, Annual Review of Ecology, Evolution, and Systematics.

[25]  S. Trumbore,et al.  Soil Organic Matter Persistence as a Stochastic Process: Age and Transit Time Distributions of Carbon in Soils , 2018, Global biogeochemical cycles.

[26]  D. Lawrence,et al.  Dependence of the evolution of carbon dynamics in the northern permafrost region on the trajectory of climate change , 2018, Proceedings of the National Academy of Sciences.

[27]  M. Mauritz,et al.  Nonlinear CO2 flux response to 7 years of experimentally induced permafrost thaw , 2017, Global change biology.

[28]  J. Chanton,et al.  Methane emissions proportional to permafrost carbon thawed in Arctic lakes since the 1950s , 2016 .

[29]  M. Mack,et al.  Nitrogen availability increases in a tundra ecosystem during five years of experimental permafrost thaw , 2016, Global change biology.

[30]  S. Natali,et al.  Old soil carbon losses increase with ecosystem respiration in experimentally thawed tundra , 2016 .

[31]  J. Cornelissen,et al.  Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic respiration in contrasting permafrost ecosystems , 2015, Global change biology.

[32]  D. Lawrence,et al.  Permafrost thaw and resulting soil moisture changes regulate projected high-latitude CO2 and CH4 emissions , 2015 .

[33]  H. Graven Impact of fossil fuel emissions on atmospheric radiocarbon and various applications of radiocarbon over this century , 2015, Proceedings of the National Academy of Sciences of the United States of America.

[34]  M. Mauritz,et al.  Experimental Warming Alters Productivity and Isotopic Signatures of Tundra Mosses , 2015, Ecosystems.

[35]  M. Mauritz,et al.  Experimental Warming Alters Productivity and Isotopic Signatures of Tundra Mosses , 2015, Ecosystems.

[36]  M. Mauritz,et al.  Permafrost thaw and soil moisture driving CO2 and CH4 release from upland tundra , 2015 .

[37]  D. M. Lawrence,et al.  Climate change and the permafrost carbon feedback , 2014, Nature.

[38]  Guido Grosse,et al.  Estimated stocks of circumpolar permafrost carbon with quantified uncertainty ranges and identified data gaps , 2014 .

[39]  M. Lupascu,et al.  Rates and radiocarbon content of summer ecosystem respiration in response to long‐term deeper snow in the High Arctic of NW Greenland , 2014 .

[40]  T. Mauritsen,et al.  Arctic amplification dominated by temperature feedbacks in contemporary climate models , 2014 .

[41]  Edward A G Schuur,et al.  Thawing permafrost increases old soil and autotrophic respiration in tundra: Partitioning ecosystem respiration using δ13C and ∆14C , 2013, Global change biology.

[42]  D. Lawrence,et al.  Diagnosing Present and Future Permafrost from Climate Models , 2012 .

[43]  Susan M. Natali,et al.  Increased plant productivity in Alaskan tundra as a result of experimental warming of soil and permafrost , 2012 .

[44]  B. Bolker,et al.  Incorporating spatial heterogeneity created by permafrost thaw into a landscape carbon estimate , 2012 .

[45]  Stephan Gruber,et al.  Derivation and analysis of a high-resolution estimate of global permafrost zonation , 2011 .

[46]  S. Natali,et al.  Effects of experimental warming of air, soil and permafrost on carbon balance in Alaskan tundra , 2011 .

[47]  E. Schuur,et al.  Response of CO2 exchange in a tussock tundra ecosystem to permafrost thaw and thermokarst development , 2009 .

[48]  M. Garnett,et al.  Bomb-14C analysis of ecosystem respiration reveals that peatland vegetation facilitates release of old carbon. , 2009 .

[49]  T. E. Osterkamp,et al.  The effect of permafrost thaw on old carbon release and net carbon exchange from tundra , 2009, Nature.

[50]  S. Trumbore Radiocarbon and Soil Carbon Dynamics , 2009 .

[51]  Marc L. Fischer,et al.  Where do fossil fuel carbon dioxide emissions from California go? An analysis based on radiocarbon observations and an atmospheric transport model , 2008 .

[52]  S. Hagemann,et al.  Vulnerability of Permafrost Carbon to Climate Change: Implications for the Global Carbon Cycle , 2008 .

[53]  M. Heimann,et al.  Terrestrial ecosystem carbon dynamics and climate feedbacks , 2008, Nature.

[54]  Christopher B. Field,et al.  Feedbacks of Terrestrial Ecosystems to Climate Change , 2007 .

[55]  M. Mack,et al.  Plant Species Composition and Productivity following Permafrost Thaw and Thermokarst in Alaskan Tundra , 2007, Ecosystems.

[56]  J. Randerson,et al.  Regional patterns of radiocarbon and fossil fuel‐derived CO2 in surface air across North America , 2007 .

[57]  C. Wirth,et al.  Reconciling Carbon-cycle Concepts, Terminology, and Methods , 2006, Ecosystems.

[58]  T. Naegler,et al.  Closing the global radiocarbon budget 1945–2005 , 2006 .

[59]  F. Chapin,et al.  Permafrost and the Global Carbon Budget , 2006, Science.

[60]  E. Davidson,et al.  Temperature sensitivity of soil carbon decomposition and feedbacks to climate change , 2006, Nature.

[61]  S. Trumbore Carbon respired by terrestrial ecosystems – recent progress and challenges , 2006 .

[62]  M. Winton,et al.  Amplified Arctic climate change: What does surface albedo feedback have to do with it? , 2006 .

[63]  Susan E. Trumbore,et al.  Partitioning sources of soil respiration in boreal black spruce forest using radiocarbon , 2006 .

[64]  D. Baldocchi Assessing the eddy covariance technique for evaluating carbon dioxide exchange rates of ecosystems: past, present and future , 2003 .

[65]  J. Randerson,et al.  Seasonal and latitudinal variability of troposphere Δ14CO2: Post bomb contributions from fossil fuels, oceans, the stratosphere, and the terrestrial biosphere , 2002 .

[66]  Susan E. Trumbore,et al.  AGE OF SOIL ORGANIC MATTER AND SOIL RESPIRATION: RADIOCARBON CONSTRAINTS ON BELOWGROUND C DYNAMICS , 2000 .

[67]  Roger G. Barry,et al.  Further statistics on the distribution of permafrost and ground ice in the Northern Hemisphere , 2000 .

[68]  A. Piquero,et al.  USING THE CORRECT STATISTICAL TEST FOR THE EQUALITY OF REGRESSION COEFFICIENTS , 1998 .

[69]  B. Stephens,et al.  Winter CO2 fluxes in a boreal forest , 1997 .

[70]  S. Trumbore,et al.  Potential responses of soil organic carbon to global environmental change. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[71]  J. Overland,et al.  Arctic Report Card 2020: Surface Air Temperature , 2020 .

[72]  N. Krakauer,et al.  Radiocarbon in the Atmosphere , 2016 .

[73]  Susan E. Trumbore,et al.  Radiocarbon Nomenclature, Theory, Models, and Interpretation: Measuring Age, Determining Cycling Rates, and Tracing Source Pools , 2016 .

[74]  E. Schuur,et al.  Radiocarbon and Climate Change: Mechanisms, Applications and Laboratory Techniques , 2016 .

[75]  S. Natali,et al.  Radiocarbon in Terrestrial Systems , 2016 .

[76]  R Core Team,et al.  R: A language and environment for statistical computing. , 2014 .

[77]  E. Schuur,et al.  Holocene Carbon Stocks and Carbon Accumulation Rates Altered in Soils Undergoing Permafrost Thaw , 2011, Ecosystems.

[78]  Eric A. Davidson,et al.  Soil carbon cycling in a temperate forest: radiocarbon-based estimates of residence times, sequestration rates and partitioning of fluxes , 2000 .

[79]  Ü. Rannik,et al.  Estimates of the annual net carbon and water exchange of forests: the EUROFLUX methodology , 2000 .

[80]  Vladimir E. Romanovsky,et al.  Evidence for warming and thawing of discontinuous permafrost in Alaska , 1999 .

[81]  E. S. Melnikov,et al.  Circum-Arctic map of permafrost and ground-ice conditions , 1997 .

[82]  S. Trumbore,et al.  Carbon isotopes for characterizing sources and turnover of nonliving organic matter , 1995 .

[83]  J. Bauer,et al.  Recovery of Submilligram Quantities of Carbon Dioxide from Gas Streams by Molecular Sieve for Subsequent Determination of Isotopic ( 13C and 14C) Natural Abundances , 1992 .

[84]  E. Feigelson The Polar Regions , 1984 .

[85]  M. Stuiver,et al.  Discussion Reporting of 14C Data , 1977, Radiocarbon.

[86]  Mikhail Kanevskiy,et al.  (www.interscience.wiley.com) DOI: 10.1002/ppp.656 Physical and Ecological Changes Associated with Warming Permafrost and Thermokarst in Interior Alaska , 2022 .