The history of Holocene atmospheric iodine over the North Atlantic

• Main Authors: Cuevas, Carlos A., Corella, Juan Pablo, Maffezzoli, N., Vallelonga, P., Spolaor, A., Cozzi, G., Müller, Julianne, Vinther, B., Barbante, C., Kjaer, H.A., Edwards, R., Saiz-Lopez, A.
• Other Authors: European Commission
• Format: Conference Object
• Language: unknown
• Published: European Geosciences Union 2020
• Subjects: Arctic; Greenland; Alfred Wegener Institute; Global warming; Ice cap; ice core; North Atlantic; ren
• Online Access: http://hdl.handle.net/10261/238102; https://doi.org/10.13039/501100000780

EGU General Assembly 2020 in the online format, 4-8 May 2020 Atmospheric iodine chemistry has a large influ-ence on the oxidizing capacity and associated radiative im-pacts in the troposphere. However, information on the evo-lution of past atmospheric iodine levels is restricted to theindustrial period while its long-term natural variability re-mains unknown. The current levels of iodine in the atmo-sphere are controlled by anthropogenic ozone deposition tothe ocean surface. Here, using high-resolution geochemicalmeasurements from coastal eastern Greenland ReCAP (REn-land ice CAP project) ice core, we report the first record ofatmospheric iodine variability in the North Atlantic duringthe Holocene (i.e., the last 11 700 years). Surprisingly, ourresults reveal that the highest iodine concentrations in therecord were found during the Holocene Thermal Maximum(HTM;~11 500¿5500 years before-present). These high io-dine levels could be driven by marine primary productivityresulting in an Early Holocene ¿biological iodine explosion¿.The high and stable iodine levels during this past warm pe-riod are a useful observational constraint on projections offuture changes in Arctic atmospheric composition and cli-mate resulting from global warming. This work was supported by CSIC. The RECAP ice coring effort was financed by the Danish Research Council through a Sapere Aude grant, the NSF through the Division of Polar Programs, the Alfred Wegener Institute, and the European Research Council under the European Community’s Seventh Framework Programme (FP7/2007-2013), and an ERC grant agreement 610055 through the Ice2Ice project and the Early Human Impact project (267696). This study has received funding from the European Research Council Executive Agency under the European Union’s Horizon 2020 Research and Innovation program (Project ERC-2016-COG 726349 CLIMAHAL)