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

Rachael H. Rhodes, Edward J. Brook, John C. H. Chiang, Thomas Blunier, Olivia J. Maselli, Joseph R. McConnell, Daniele Romanini, Jeffrey P. Severinghaus

Research output: Contribution to journalArticlepeer-review

70 Citations (Scopus)

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.
Original languageEnglish
Pages (from-to)1016-1019
Number of pages4
JournalScience
Volume348
Issue number6238
DOIs
Publication statusPublished - 29 May 2015

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