Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes

  title={Collapse and rapid resumption of Atlantic meridional circulation linked to deglacial climate changes},
  author={Jerry F. McManus and Roger Francois and J. M. Gherardi and L. D. Keigwin and S. L. R. Brown-Leger},
The Atlantic meridional overturning circulation is widely believed to affect climate. Changes in ocean circulation have been inferred from records of the deep water chemical composition derived from sedimentary nutrient proxies, but their impact on climate is difficult to assess because such reconstructions provide insufficient constraints on the rate of overturning. Here we report measurements of 231Pa/230Th, a kinematic proxy for the meridional overturning circulation, in a sediment core from… 

Estimated strength of the Atlantic overturning circulation during the last deglaciation

The Atlantic meridional overturning circulation affects the latitudinal distribution of heat, and is a key component of the climate system. Proxy reconstructions, based on sedimentary 231 Pa= 230 Th

Extreme deepening of the Atlantic overturning circulation during deglaciation

Glacial terminations during the late Pleistocene epoch are associated with changes in insolation. They are also punctuated by millennial-scale climate shifts, characterized by a weakening and

Constraining the Variability of the Atlantic Meridional Overturning Circulation During the Holocene

There is a converging body of evidence supporting a measurable slowdown of the Atlantic Meridional Overturning Circulation (AMOC) as climate warms and Northern Hemisphere ice sheets inexorably

Accelerated drawdown of meridional overturning in the late‐glacial Atlantic triggered by transient pre‐H event freshwater perturbation

Abrupt decreases of the Atlantic meridional overturning circulation (MOC) during the Late Pleistocene have been directly linked to catastrophic discharges of glacimarine freshwater, triggering

Coherent deglacial changes in western Atlantic Ocean circulation

A consistent signal of the 231Pa/230Th proxy reveals a spatially coherent picture of western Atlantic circulation changes over the last deglaciation, which reveals a two-step AMOC slowdown at the beginning of the deglacial period.

Strength and geometry of the glacial Atlantic Meridional Overturning Circulation

During the Last Glacial Maximum, the pattern of Atlantic Meridional Overturning Circulation was different from today. A combination of sediment chemistry and a scavenging model suggests that the

North Atlantic ocean circulation and abrupt climate change during the last glaciation

Climate and ocean circulation proxies are examined at high resolution in a deep North Atlantic sediment core, suggesting reduced Atlantic overturning circulation during every cool northern stadial, with the greatest reductions during episodic Hudson Strait iceberg discharges, while sharp northern warming followed reinvigorated overturning.

Abrupt pre-Bølling–Allerød warming and circulation changes in the deep ocean

It is shown that the release of heat from warm waters in the deep North Atlantic Ocean probably triggered the Bølling–Allerød warming and reinvigoration of the Atlantic meridional overturning circulation, and the depleted radiocarbon content of the warm and salty water mass implies a long-term disconnect from rapid surface exchanges, and is most consistent with a Southern Ocean source.



Evidence for changes in the North Atlantic Deep Water linked to meltwater surges during the Heinrich events

Changes in surface salinity of the North Atlantic Ocean during the last deglaciation

ABRUPT and short climate changes, such as the Younger Dryas, punctuated the last glacial-to-interglacial transition1–4. Broecker et al.5 proposed that these may have been caused by an interruption of

Evidence for massive discharges of icebergs into the North Atlantic ocean during the last glacial period

SEDIMENTS in the North Atlantic ocean contain a series of layers that are rich in ice-rafted debris and unusually poor in foraminifera1. Here we present evidence that the most recent six of these

Deglacial sea-level record from Tahiti corals and the timing of global meltwater discharge

THE timing of the last deglaciation is important to our understanding of the dynamics of large ice sheets1 and their effects on the Earth's surface2,3. Moreover, the disappearance of the glacial ice

A 0.5-million-year record of millennial-scale climate variability in the north atlantic

Long, continuous, marine sediment records from the subpolar North Atlantic document the glacial modulation of regional climate instability throughout the past 0.5 million years, which characterizes nearly all observed climate states.

Constraints from paleotracer data on the North Atlantic circulation during the Last Glacial Maximum

We investigate the extent to which the paleotracers, δ13C and δ18O, constrain the North Atlantic Ocean general circulation during the last glacial maximum (LGM). The distinction is made in this work

Deglacial changes in ocean circulation from an extended radiocarbon calibration

Temporal variations in the atmospheric concentration of radiocarbon sometimes result in radiocarbon-based age-estimates of biogenic material that do not agree with true calendar age. This problem is

Abrupt climate change at the end of the last glacial period inferred from trapped air in polar Ice

Nitrogen and argon isotopes in trapped air in Greenland ice show that the Greenland Summit warmed 9 +/- 3 degrees C over a period of several decades, beginning 14,672 years ago, supporting a North Atlantic rather than a tropical trigger for the climate event.