Article abstract
Nature Geoscience 1, 787 - 792 (2008)
Published online: 21 September 2008 | doi:10.1038/ngeo311
Subject Category: Palaeoclimate and palaeoceanography
Antarctic temperature at orbital timescales controlled by local summer duration
Peter Huybers1 & George Denton2
Abstract
During the late Pleistocene epoch, proxies for Southern Hemisphere climate from the Antarctic ice cores vary nearly in phase with Northern Hemisphere insolation intensity at the precession and obliquity timescales. This coherence has led to the suggestion that Northern Hemisphere insolation controls Antarctic climate. However, it is unclear what physical mechanisms would tie southern climate to northern insolation. Here we call on radiative equilibrium estimates to show that Antarctic climate could instead respond to changes in the duration of local summer. Simple radiative equilibrium dictates that warmer annual average atmospheric temperatures occur as a result of a longer summer, as opposed to a more intense one, because temperature is more sensitive to insolation when the atmosphere is cooler. Furthermore, we show that a single-column atmospheric model reproduces this radiative equilibrium effect when forced exclusively by local Antarctic insolation, generating temperature variations that are coherent and in phase with proxies of Antarctic atmospheric temperature and surface conditions. We conclude that the duration of Southern Hemisphere summer is more likely to control Antarctic climate than the intensity of Northern Hemisphere summer with which it (often misleadingly) covaries. In our view, near interhemispheric climate symmetry at the obliquity and precession timescales arises from a northern response to local summer intensity and a southern response to local summer duration.
- Harvard University, Cambridge, Massachusetts 02138, USA
- University of Maine, Orono, Maine 04469, USA
Correspondence to: Peter Huybers1 e-mail: phuybers@fas.harvard.edu
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated.
NEWS AND VIEWS
Global change Climate's astronomical sensorsNature News and Views (06 Nov 2008)
Contrasts in Vostok core ? changes in climate or ice volume?Nature News and Views (15 Aug 1985)
See all 8 matches for News And ViewsRESEARCH
Northern Hemisphere forcing of climatic cycles in Antarctica over the past 360,000 yearsNature Letters to Editor (23 Aug 2007)
Vostok ice core: a continuous isotope temperature record over the last climatic cycle (160,000 years)Nature Article (01 Oct 1987)
See all 68 matches for Research
