Focus |

Ocean conveyor and climate

The ocean overturning circulation has been compared to a conveyor belt that transports heat and salt, as well as carbon and other elements around the globe. The initial schematic of this global ocean circulation has been enriched with added loops and more sophisticated pathways. But the vertical exchange of water between surface and abyss in the northern North Atlantic and the high southern latitudes continues to be an important determinant of the vigour of the circulation. In this focus, we present a collection of research articles and opinion pieces that explore the interplay between ocean overturning in the north and south and climate change.

Content

  • Nature Geoscience | Editorial

    The ocean overturning circulation is potentially sensitive to climate change. In the north and south alike, human influence is less pronounced than we thought, but that is no reason to relax our watchfulness.

  • Nature Geoscience | News & Views

    A weakening of the Atlantic meridional overturning circulation has emerged from noise after years of painstaking measurements. Three independent lines of evidence suggest that an anthropogenic influence on this overturning is not yet detectable.

    • Thomas W. N. Haine
  • Nature Geoscience | News & Views

    Conversion of Antarctic circumpolar upwelling waters to less dense water has mainly been attributed to surface heat fluxes. An analysis of water-mass transformation shows that the dominant process is the formation of sea ice near Antarctica and its melt offshore.

    • Nathaniel L. Bindoff
    •  &  William R. Hobbs
  • Nature Geoscience | Letter

    The mid-1990s’ warming of the North Atlantic subpolar gyre was probably related to strengthened overturning. Observations and numerical models suggest that a climate reversal to a cooling trend occurred around 2005.

    • Jon Robson
    • , Pablo Ortega
    •  &  Rowan Sutton

From the archives

  • Nature Geoscience | Letter

    The exchange of water across the Antarctic continental shelf break brings warm waters towards ice shelves and glacier grounding lines. Ocean glider observations reveal that eddy-induced transport contributes significantly to this exchange.

    • Andrew F. Thompson
    • , Karen J. Heywood
    • , Sunke Schmidtko
    •  &  Andrew L. Stewart
  • Nature Geoscience | Letter

    In the Southern Ocean, deep-water masses of the world ocean upwell to the surface and subsequently sink to intermediate and abyssal depths in two overturning cells. Observational evidence relates changes in abyssal mixing—a key influence on the lower cell—to oceanic eddy variability.

    • K. L. Sheen
    • , A. C. Naveira Garabato
    • , J. A. Brearley
    • , M. P. Meredith
    • , K. L. Polzin
    • , D. A. Smeed
    • , A. Forryan
    • , B. A. King
    • , J-B. Sallée
    • , L. St. Laurent
    • , A. M. Thurnherr
    • , J. M. Toole
    • , S. N. Waterman
    •  &  A. J. Watson
  • Nature Geoscience | Letter

    In the tropics, substantially more rain falls just north of the Equator. An analysis of satellite observations, reanalysis data and model simulations suggests that the meridional ocean overturning circulation contributes significantly to the tropical rainfall peak north of the Equator.

    • Dargan M. W. Frierson
    • , Yen-Ting Hwang
    • , Neven S. Fučkar
    • , Richard Seager
    • , Sarah M. Kang
    • , Aaron Donohoe
    • , Elizabeth A. Maroon
    • , Xiaojuan Liu
    •  &  David S. Battisti
  • Nature Geoscience | Article

    Uptake of atmospheric carbon dioxide in the subpolar North Atlantic Ocean declined rapidly between 1990 and 2006. An analysis of oceanographic data suggests that the slowdown of the meridional overturning circulation was largely responsible.

    • Fiz F. Pérez
    • , Herlé Mercier
    • , Marcos Vázquez-Rodríguez
    • , Pascale Lherminier
    • , Anton Velo
    • , Paula C. Pardo
    • , Gabriel Rosón
    •  &  Aida F. Ríos
  • Nature Geoscience | Article

    Hydrographic properties of the North Atlantic Ocean have changed significantly over the past decades. A combination of changes in seawater density, calculated from observed properties of sea water and a numerical ocean model, reveals that the strength of the meridional overturning circulation has changed in different directions in the subpolar and subtropical basins, respectively.

    • M. Susan Lozier
    • , Vassil Roussenov
    • , Mark S. C. Reed
    •  &  Richard G. Williams