Southern Hemisphere climate variability forced by Northern Hemisphere ice-sheet topography

T. R. Jones, W. H. G. Roberts, E. J. Steig, K. M. Cuffey, B. R. Markle, J. W. C. White

Research output: Contribution to journalLetterpeer-review

30 Citations (Scopus)

Abstract

The presence of large Northern Hemisphere ice sheets and reduced greenhouse gas concentrations during the Last Glacial Maximum fundamentally altered global ocean–atmosphere climate dynamics1. Model simulations and palaeoclimate records suggest that glacial boundary conditions affected the El Niño–Southern Oscillation2,3, a dominant source of short-term global climate variability. Yet little is known about changes in short-term climate variability at mid- to high latitudes. Here we use a high-resolution water isotope record from West Antarctica to demonstrate that interannual to decadal climate variability at high southern latitudes was almost twice as large at the Last Glacial Maximum as during the ensuing Holocene epoch (the past 11,700 years). Climate model simulations indicate that this increased variability reflects an increase in the teleconnection strength between the tropical Pacific and West Antarctica, owing to a shift in the mean location of tropical convection. This shift, in turn, can be attributed to the influence of topography and albedo of the North American ice sheets on atmospheric circulation. As the planet deglaciated, the largest and most abrupt decline in teleconnection strength occurred between approximately 16,000 years and 15,000 years ago, followed by a slower decline into the early Holocene.
Original languageEnglish
Pages (from-to)351-355
JournalNature
Volume554
Issue number7692
Early online date5 Feb 2018
DOIs
Publication statusPublished - 15 Feb 2018
Externally publishedYes

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