A Big Enough Flood

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May 26, 2021 by Helen Hill

story by Helen Hill for MITgcm

WHOI Geologist Alan Condron’s research focuses on trying to understand why the Earth’s climate can abruptly change and how likely it is to suddenly change in the future. A particular interest is Dansgaard-Oeschger events – short-lived global climatic swings characterized by a period of abrupt warming followed by a period of slow cooling that occurred during the last ice age. Probably the most well-known is the Younger Dryas (around 12,900 to 11,700 years BP) when a period of re-glaciation temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM) started receding around 20,000 BP.

In a 2020 study using the ocean/sea-ice implementation of MITgcm described in Condron et al. (2009) and Hill and Condron (2014), Condron and his collaborators UMass Amherst geologists Anthony J. Joyce and Raymond S. Bradley, ran experiments to estimate the volume of freshwater that the Arctic Ocean stored as sea ice prior to deglaciation, and to quantify whether deglacial changes in ice export were large enough to slow the AMOC and cool climate.

Condron says researchers once thought the Younger Dryas cold period was triggered by the draining of Lake Agassiz, an enormous glacial lake at the edge of the massive ice sheet that once extended from the Arctic south into modern New York. “But although the lake was big by modern standards, it has been difficult in the climate modeling community to trigger a 1,000-year cold period with the water it contained, because the volume of water is not large enough to weaken the Atlantic circulation over a long period,” he says. “However, the volumes of water we find stored as sea ice in the Arctic vastly exceed the volume of Lake Agassiz, making sea ice break-up a really good candidate for triggering the Younger Dryas cooling.”

“Thick ice over the Arctic Ocean created an enormous reservoir of freshwater, independent of terrestrial sources,” says Condron. “As ice sheets retreated and sea level rose, changes in atmospheric circulation and land-based floods caused this ice to flow to the sea through Fram Strait east of Greenland, where it melted and freshened Nordic Seas enough to weaken Atlantic circulation.”

“As both the volume of ice stored in the Arctic Basin and the magnitude of these export events far exceed the volume of meltwater discharged from Lake Agassiz, our results demonstrate that ice from the Arctic Ocean itself may have played an important role in causing abrupt climate change in the past.”

To find out more about this work contact acondron@whoi.edu

Story image credit: Rawpixel

About the Researcher

Alan Condron is an Assistant Scientist at the Geology and Geophysics Department at Woods Hole Oceanographic Institution. He holds a PhD (2006) from the University of Sheffield in the UK. Condron uses numerical models to understand Climate Change. He has been using MITgcm since 2007.


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This Month’s Featured Publication

Related Publications

Condron, A., Winsor, P., Hill, C., and Menemenlis, D. (2009), Simulated Response of the Arctic Freshwater Budget to Extreme NAO Wind Forcing, Journal of Climate, doi: 10.1175/2008JCLI2626.1

Hill, J.C. and Condron, A. (2014), Subtropical iceburg scours and meltwater routing in the deglacial western North Atlantic, Nature Geoscience, doi: 10.1038/ngeo2267

Other New Publications this Month

EGU General Assembly 2021 papers

Brisc, F. and Serra, N.: Immersive Visualization of Ocean Data in a Game Engine, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12491, https://doi.org/10.5194/egusphere-egu21-12491, 2021

Du, J., Zhang, X., Ye, Y., Völker, C., and Tian, J.: Southern control of interhemispheric synergy on marine carbon sequestration during glacial cycles, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9623, https://doi.org/10.5194/egusphere-egu21-9623, 2021

Kehl, C., Reijnders, D., Fischer, R., Brouwer, R., Schram, R., and van Sebille, E.: Parcels 2.2 – An increasingly versatile, open-source Lagrangian ocean simulation tool, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1033, https://doi.org/10.5194/egusphere-egu21-1033, 2021

Love, R., Andres, H., Condron, A., Zhang, X., Lohmann, G., and Tarasov, L.: Towards more physically constrained freshwater injection via eddy permitting simulations of the last glacial cycle, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10357, https://doi.org/10.5194/egusphere-egu21-10357, 2021

Goldsworth, F., Marshall, D., and Johnson, H.: Symmetric (inertial) instability in cross-equatorial western boundary currents, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1159, https://doi.org/10.5194/egusphere-egu21-1159, 2021

Gonzalez, N., Waldman, R., Sannino, G., Giordani, H., and Somot, S.: A new perspective on tidal mixing at the Strait of Gibraltar from a very high-resolution model of the Mediterranean Sea, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3971, https://doi.org/10.5194/egusphere-egu21-3971, 2021

Pendleton, S., Condron, A., and Donnelly, J.: Hudson valley floods an unlikely trigger for Inter-Allerød Cold Period (IACP) cooling 13,300 years ago, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12829, https://doi.org/10.5194/egusphere-egu21-12829, 2021

Strobach, E., Molod, A., Trayanov, A., Putman, W., Menemenlis, D., Klein, P., Campin, J.-M., Hill, C., and Henze, C.: GEOS-MITgcm coupled atmosphere-ocean simulation for DYAMOND, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14947, https://doi.org/10.5194/egusphere-egu21-14947, 2021

April 2021 Journal Publications

Brisc F. and N. Serra (2021), Real-time Immersive VR Visualization of Ocean Climate Data, 2021 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW), doi: 10.1109/VRW52623.2021.00051

De Andrés E, Otero J, Navarro, FJ, Walczowski W (2021), Glacier–plume or glacier–fjord circulation models? A 2-D comparison for Hansbreen–Hansbukta system, Svalbard, Journal of Glaciology, doi: 10.1017/jog.2021.27

T. Duda et al (2021), Effects of Pacific Summer Water layer variations and ice cover on Beaufort Sea underwater sound ducting, The Journal of the Acoustical Society of America, doi: 10.1121/10.0003929

T.J. Fauches et al (2021), TRAPPIST Habitable Atmosphere Intercomparison (THAI) workshop report, arXiv: 2104.01091 [ astro-ph.EP]

Y. Feng et al (2021), Improved representation of river runoff in Estimating the Circulation and Climate of the Ocean Version 4 (ECCOv4) simulations: implementation, evaluation, and impacts to coastal plume regions, Geosci. Model Dev., doi: 10.5194/gmd-14-1801-2021

F.W. Goldsworth et al (2021), Symmetric instability in cross-equatorial western boundary currents, Journal of Physical Oceanography, doi: 10.1175/JPO-D-20-0273.1

G. Gopalakrishnan et al (2021), State estimates and forecasts of the eddy field in the Subtropical Countercurrent in the Northern Philippine Sea, Journal of Atmospheric and Oceanic Technology, doi: 10.1175/JTECH-D-20-0083.1

Kaitlin A. Naughten et al (2021), Two-timescale response of a large Antarctic ice shelf to climate change, Nature Communications, doi: 10.1038/s41467-021-22259-0

Wanying Kang et al (2021), How does salinity shape ocean circulation and ice geometry on Enceladus and other icy satellites? arXiv: 2104.07008 [astro-ph.EP]

G. Le Gland (2021), SPEAD 1.0 – Simulating Plankton Evolution with Adaptive Dynamics in a two-trait continuous fitness landscape applied to the Sargasso Sea, Geosci. Model Dev., doi: 10.5194/gmd-14-1949-2021

Zhenyu Liu et al (2021), Observational characteristics and dynamic mechanism of low-salinity water lens for the offshore detachment of the Changjiang River diluted water in August 2006, Acta Oceanologica Sinica, doi: 10.1007/s13131-021-1710-9

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