Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 438 (7068), 655-7

Slowing of the Atlantic Meridional Overturning Circulation at 25 Degrees N

Affiliations

Slowing of the Atlantic Meridional Overturning Circulation at 25 Degrees N

Harry L Bryden et al. Nature.

Abstract

The Atlantic meridional overturning circulation carries warm upper waters into far-northern latitudes and returns cold deep waters southward across the Equator. Its heat transport makes a substantial contribution to the moderate climate of maritime and continental Europe, and any slowdown in the overturning circulation would have profound implications for climate change. A transatlantic section along latitude 25 degrees N has been used as a baseline for estimating the overturning circulation and associated heat transport. Here we analyse a new 25 degrees N transatlantic section and compare it with four previous sections taken over the past five decades. The comparison suggests that the Atlantic meridional overturning circulation has slowed by about 30 per cent between 1957 and 2004. Whereas the northward transport in the Gulf Stream across 25 degrees N has remained nearly constant, the slowing is evident both in a 50 per cent larger southward-moving mid-ocean recirculation of thermocline waters, and also in a 50 per cent decrease in the southward transport of lower North Atlantic Deep Water between 3,000 and 5,000 m in depth. In 2004, more of the northward Gulf Stream flow was recirculating back southward in the thermocline within the subtropical gyre, and less was returning southward at depth.

Comment in

Similar articles

  • The Role of the Gulf Stream in European Climate
    JB Palter. Ann Rev Mar Sci 7, 113-37. PMID 25560606. - Review
    The Gulf Stream carries the warm, poleward return flow of the wind-driven North Atlantic subtropical gyre and the Atlantic Meridional Overturning Circulation. This northw …
  • Atlantic Meridional Overturning Circulation Slowdown Cooled the Subtropical Ocean
    SA Cunningham et al. Geophys Res Lett 40 (23), 6202-6207. PMID 26074634.
    [1] Observations show that the upper 2 km of the subtropical North Atlantic Ocean cooled throughout 2010 and remained cold until at least December 2011. We show that thes …
  • Recent Changes in the North Atlantic
    RR Dickson et al. Philos Trans A Math Phys Eng Sci 361 (1810), 1917-33; discussion 1933-4. PMID 14558901.
    It has long been recognized that the Atlantic meridional overturning circulation (MOC) is potentially sensitive to greenhouse-gas and other climate forcing, and that chan …
  • A Sea Change in Our View of Overturning in the Subpolar North Atlantic
    MS Lozier et al. Science 363 (6426), 516-521. PMID 30705189.
    To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st …
  • Overturning in the North Atlantic
    MS Lozier. Ann Rev Mar Sci 4, 291-315. PMID 22457977. - Review
    The global overturning of ocean waters involves the equatorward transport of cold, deep waters and the poleward transport of warm, near-surface waters. Such movement crea …
See all similar articles

Cited by 9 PubMed Central articles

See all "Cited by" articles

LinkOut - more resources

Feedback