title: Permafrost thawing as a possible source of abrupt carbon release at the onset of the Bølling/Allerød.
abstract: One of the most abrupt and yet unexplained past rises in atmospheric CO2 (>10 p.p.m.v. in two centuries) occurred in quasi-synchrony with abrupt northern hemispheric warming into the Bølling/Allerød, ~14,600 years ago. Here we use a U/Th-dated record of atmospheric Δ(14)C from Tahiti corals to provide an independent and precise age control for this CO2 rise. We also use model simulations to show that the release of old (nearly (14)C-free) carbon can explain these changes in CO2 and Δ(14)C. The Δ(14)C record provides an independent constraint on the amount of carbon released (~125 Pg C). We suggest, in line with observations of atmospheric CH4 and terrigenous biomarkers, that thawing permafrost in high northern latitudes could have been the source of carbon, possibly with contribution from flooding of the Siberian continental shelf during meltwater pulse 1A. Our findings highlight the potential of the permafrost carbon reservoir to modulate abrupt climate changes via greenhouse-gas feedbacks.
authors.affiliation: Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung (AWI), P.O. Box 12 01 61, D-27515 Bremerhaven, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Köhler
authors.affiliation: 1] Alfred-Wegener-Institut Helmholtz-Zentrum für Polar-und Meeresforschung (AWI), P.O. Box 12 01 61, D-27515 Bremerhaven, Germany [2] School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, UK.
authors.forename: Gregor
authors.initials: G
authors.lastname: Knorr
authors.affiliation: CEREGE, Aix Marseille University, CNRS, IRD, College de France, B.P. 80 Technopole de l'Arbois, 13545 Aix-en-Provence, France.
authors.forename: Edouard
authors.initials: E
authors.lastname: Bard