Enhanced tropical methane production in response to iceberg discharge in the North Atlantic

The causal mechanisms responsible for the abrupt climate changes of the Last Glacial Period remain unclear. One major difficulty is dating ice-rafted debris deposits associated with Heinrich events: Extensive iceberg influxes into the North Atlantic Ocean linked to global impacts on climate and biog...

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Bibliographic Details
Published in:Science
Main Authors: Rhodes, Rachael H., Brook, Edward J., Chiang, John C. H., Blunier, Thomas, Maselli, Olivia J., McConnell, Joseph R., Romanini, Daniele, Severinghaus, Jeffrey P.
Format: Article in Journal/Newspaper
Language:unknown
Published: American Association for the Advancement of Science 2015
Subjects:
F800 Physical and Terrestrial Geographical and Environmental Sciences
Greenland
Hudson
Hudson Strait
ice core
North Atlantic
Online Access:https://nrl.northumbria.ac.uk/id/eprint/37618/
https://doi.org/10.1126/science.1262005
Description
Summary:The causal mechanisms responsible for the abrupt climate changes of the Last Glacial Period remain unclear. One major difficulty is dating ice-rafted debris deposits associated with Heinrich events: Extensive iceberg influxes into the North Atlantic Ocean linked to global impacts on climate and biogeochemistry. In a new ice core record of atmospheric methane with ultrahigh temporal resolution, we find abrupt methane increases within Heinrich stadials 1, 2, 4, and 5 that, uniquely, have no counterparts in Greenland temperature proxies. Using a heuristic model of tropical rainfall distribution, we propose that Hudson Strait Heinrich events caused rainfall intensification over Southern Hemisphere land areas, thereby producing excess methane in tropical wetlands. Our findings suggest that the climatic impacts of Heinrich events persisted for 740 to 1520 years.

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