Abrupt reversal in ocean overturning during the Palaeocene/Eocene warm period

Nunes, Flavia; Norris, Richard D.
January 2006
Nature;1/5/2006, Vol. 439 Issue 7072, p60
Academic Journal
An exceptional analogue for the study of the causes and consequences of global warming occurs at the Palaeocene/Eocene Thermal Maximum, 55 million years ago. A rapid rise of global temperatures during this event accompanied turnovers in both marine and terrestrial biota, as well as significant changes in ocean chemistry and circulation. Here we present evidence for an abrupt shift in deep-ocean circulation using carbon isotope records from fourteen sites. These records indicate that deep-ocean circulation patterns changed from Southern Hemisphere overturning to Northern Hemisphere overturning at the start of the Palaeocene/Eocene Thermal Maximum. This shift in the location of deep-water formation persisted for at least 40,000 years, but eventually recovered to original circulation patterns. These results corroborate climate model inferences that a shift in deep-ocean circulation would deliver relatively warmer waters to the deep sea, thus producing further warming. Greenhouse conditions can thus initiate abrupt deep-ocean circulation changes in less than a few thousand years, but may have lasting effects; in this case taking 100,000 years to revert to background conditions.


Related Articles

  • Response of Southern Ocean circulation to global warming may enhance basal ice shelf melting around Antarctica. Hattermann, Tore; Levermann, Anders // Climate Dynamics;Oct2010, Vol. 35 Issue 5, p741 

    We investigate the large-scale oceanic features determining the future ice shelf-ocean interaction by analyzing global warming experiments in a coarse resolution climate model with a comprehensive ocean component. Heat and freshwater fluxes from basal ice shelf melting (ISM) are parameterized...

  • Astronomical pacing of late Palaeocene to early Eocene global warming events. Lourens, Lucas J.; Sluijs, Appy; Kroon, Dick; Zachos, James C.; Thomas, Ellen; Röhl, Ursula; Bowles, Julie; Raffi, Isabella // Nature;6/23/2005, Vol. 435 Issue 7045, p1083 

    At the boundary between the Palaeocene and Eocene epochs, about 55 million years ago, the Earth experienced a strong global warming event, the Palaeocene–Eocene thermal maximum. The leading hypothesis to explain the extreme greenhouse conditions prevalent during this period is the...

  • The Early Twentieth-Century Warming in the Arctic—A Possible Mechanism. Bengtsson, Lennart; Semenov, Vladimir A.; Johannessen, Ola M. // Journal of Climate;Oct2004, Vol. 17 Issue 20, p4045 

    The huge warming of the Arctic that started in the early 1920s and lasted for almost two decades is one of the most spectacular climate events of the twentieth century. During the peak period 1930–40, the annually averaged temperature anomaly for the area 60°–90°N amounted to...

  • Where's the heat? Washington, Warren M. // Natural History;Mar90, Vol. 99 Issue 3, p66 

    Examines the difficulties faced in the process of compiling evidence of global warming. Conflicting statistics; Role of the oceans in response to increased greenhouse gases; Efforts to accurately study the phenomena of global warming; Measurements of surface and deep ocean currents; Physics of...

  • Rapid freshening of North Atlantic could cool northern winters.  // Oceanus;2005, Vol. 44 Issue 2, p6 

    This article reports that large and climatically sensitive regions of the North Atlantic Ocean have become less salty since the late 1960s, a trend that could alter global ocean circulation and spur climate changes by the 21st century. Reporting in the June 17 edition of the journal "Science,"...

  • Sensitivity of North Atlantic subpolar gyre and overturning to stratification-dependent mixing: response to global warming. Marzeion, Ben; Levermann, Anders; Mignot, Juliette // Climate Dynamics;Apr2010, Vol. 34 Issue 5, p661 

    We use a reduced complexity climate model with a three-dimensional ocean component and realistic topography to investigate the effect of stratification-dependent mixing on the sensitivity of the North Atlantic subpolar gyre (SPG), and the Atlantic meridional overturning circulation (AMOC), to...

  • Global Warming and the Weakening of the Tropical Circulation. Vecchi, Gabriel A.; Soden, Brian J. // Journal of Climate;Sep2007, Vol. 20 Issue 17, p4316 

    This study examines the response of the tropical atmospheric and oceanic circulation to increasing greenhouse gases using a coordinated set of twenty-first-century climate model experiments performed for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The...

  • UNDERSTANDING EL NI�O. Whitaker, Richard // Geodate;May2007, Vol. 20 Issue 2, p6 

    The article provides information on El Ni�o phenomenon. The work of Gilbert Walker, a director-general of British Observatories in India, has linked the El Ni�o of the Peruvian fishermen with the warming of the tropical central and eastern Pacific ocean. A map has been compiled by the...

  • Global Environmental Concepts.  // Greece Country Review;2010, p142 

    The article offers information on the different global environmental concepts including the greenhouse effect, the relationship between global warming and greenhouse gases and international policy development in regard to global warming.


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics