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

Rhodes, Rachael H., Brook, Edward J., Chiang, John C. H., Blunier, Thomas, Maselli, Olivia J., McConnell, Joseph R., Romanini, Daniele and Severinghaus, Jeffrey P. (2015) Enhanced tropical methane production in response to iceberg discharge in the North Atlantic. Science, 348 (6238). pp. 1016-1019. ISSN 0036-8075

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Abstract

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.

Item Type:	Article
Subjects:	F800 Physical and Terrestrial Geographical and Environmental Sciences
Department:	Faculties > Engineering and Environment > Geography and Environmental Sciences
Depositing User:	Elena Carlaw
Date Deposited:	17 Jan 2019 10:20
Last Modified:	10 Oct 2019 23:15
URI:	http://nrl.northumbria.ac.uk/id/eprint/37618

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