NEEM Ice Core 120,000 Year Bromine and Sodium Data Spolaor, A.; Vallelonga, P.; Turetta, C.; Maffezzoli, N.; Cozzi, G.; Gabrieli, J.; Barbante, C.; Goto-Azuma, K.; Saiz-Lopez, A.; Cuevas, C.A.; Dahl-Jensen, D. Spolaor, A. Vallelonga, P. Turetta, C. Maffezzoli, N. Cozzi, G. Gabrieli, J. Barbante, C. Goto-Azuma, K. Saiz-Lopez, A. Cuevas, C.A. Dahl-Jensen, D. sea ice earth science/paleoclimate/ice cores (bromine,bulk ice,null,nanogram per gram,null,ice cores,null,inductively-coupled plasma field sector mass spectrometry,N,null) earth science/paleoclimate/ice cores (depth,null,null,meter,null,ice cores,null,null,N,null) earth science/paleoclimate/ice cores (delta 18O,bulk ice,null,per mil SMOW,null,ice cores,null,cavity ring-down spectroscopy,N,null) earth science/paleoclimate/ice cores (sodium,bulk ice,null,nanogram per gram,null,ice cores,null,inductively-coupled plasma field sector mass spectrometry,N,null) earth science/paleoclimate/ice cores (bromine,bulk ice,null,dimensionless,null,ice cores,null,null,N,bromine enrichment value) earth science/paleoclimate/ice core (NEEM>LATITUDE 77.45>LONGITUDE -51.06) Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called "bromine explosions" and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2C global average warming target of the recent COP21 Paris climate agreement. STUDY NOTES: Bromine, sodium and bromine enrichment data used to reconstruct Canadian Arctic sea ice over the past 120 ky NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Spolaor, A. Investigator : Vallelonga, P. Investigator : Turetta, C. Investigator : Maffezzoli, N. Investigator : Cozzi, G. Investigator : Gabrieli, J. Investigator : Barbante, C. Investigator : Goto-Azuma, K. Investigator : Saiz-Lopez, A. Investigator : Cuevas, C.A. Investigator : Dahl-Jensen, D. 2016-09-23 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/20528 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2016br.txt https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2016br.txt English https://www.ncdc.noaa.gov/paleo/study/20528 https://www1.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/neem/neem2016br.txt Andrea Spolaor, Paul Vallelonga, Clara Turetta, Niccolo Maffezzoli, Giulio Cozzi, Jacopo Gabrieli, Carlo Barbante, Kumiko Goto-Azuma, Alfonso Saiz-Lopez, Carlos A. Cuevas, and Dorthe Dahl-Jensen2016Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice coreScientific Reports33925610.1038/srep33925http://dx.doi.org/10.1038/srep33925 START YEAR: 120295 cal yr BP * END YEAR: -24 cal yr BP -51.06 77.45 -51.06 77.45