Climate Evolution in the Northern North Atlantic – 15 Ma to Present

Abstract. Although the Last Interglacial (LIG) is often considered as a possible analogue for future climate in high latitudes, its precise climate evolution and associated causes remain uncertain. Here we compile high-resolution marine sediment records from the North Atlantic, Labrador Sea, Norwegian Sea and the Southern Ocean. We document a delay in the establishment of peak interglacial conditions in the North Atlantic, Labrador and Norwegian Seas as compared to the Southern Ocean. In particular, we observe a persistent iceberg melting at high northern latitudes at the beginning of the LIG. It suggests that the input of meltwater has maintained (1) colder and fresher surface-water conditions in the North Atlantic, Labrador and Norwegian Seas and (2) weaker ventilation of North Atlantic deep waters during the early LIG (129–125.5 ka) compared to the late LIG. Results from an ocean-atmosphere coupled model with insolation as a sole forcing for three key periods of the LIG show that insolation variations alone lead to warmer North Atlantic surface waters and stronger Atlantic overturning during the early LIG (126 ka) than the late LIG (122 ka). Hence insolation variations alone do not explain the delay in peak interglacial conditions observed at high northern latitudes. When freshwater input is interactively computed at 126 ka in response to the high boreal summer insolation, the model simulates colder, fresher North Atlantic surface waters and weaker Atlantic overturning during the early LIG (126 ka) compared to the late LIG (122 ka). This result indicates that both insolation variations and ice sheet melting have to be considered to reproduce the LIG climate evolution and supports our hypothesis that optimal thermal and deep ocean circulation conditions at high northern latitudes develop during the late LIG only, when the freshwater supply has already ceased.

Download Full-text

Consistency of the multi-model CMIP5/PMIP3-past1000 ensemble

Climate of the Past Discussions ◽

10.5194/cpd-9-3789-2013 ◽

2013 ◽

Vol 9 (4) ◽

pp. 3789-3824 ◽

Cited By ~ 1

Author(s):

O. Bothe ◽

J. H. Jungclaus ◽

D. Zanchettin

Keyword(s):

Air Temperature ◽

North Atlantic ◽

North Pacific ◽

Surface Air Temperature ◽

Temperature Data ◽

The Other ◽

Last Millennium ◽

Ensemble Simulations ◽

The Pacific ◽

Climate Evolution

Abstract. We present an assessment of the probabilistic and climatological consistency of the CMIP5/PMIP3 ensemble simulations for the last millennium relative to proxy-based reconstructions under the paradigm of a statistically indistinguishable ensemble. We evaluate whether simulations and reconstructions are compatible realizations of the unknown past climate evolution. A lack of consistency is diagnosed in surface air temperature data for the Pacific, European and North Atlantic regions. On the other hand, indications are found that temperature signals partially agree in the western tropical Pacific, the subtropical North Pacific and the South Atlantic. Deviations from consistency may change between sub-periods, and they may include pronounced opposite biases in different sub-periods. These distributional inconsistencies originate mainly from differences in multi-centennial to millennial trends. Since the data uncertainties are only weakly constrained, the frequent over-dispersive distributional relations prevent the formal rejection of consistency of the simulation ensemble.

Download Full-text

Holocene Climate Evolution of the North Atlantic Ocean and the Nordic Seas — a Synthesis of New Results

Climate Development and History of the North Atlantic Realm ◽

10.1007/978-3-662-04965-5_11 ◽

2002 ◽

pp. 165-173 ◽

Cited By ~ 8

Author(s):

Nalân Koç ◽

Eystein Jansen

Keyword(s):

Atlantic Ocean ◽

North Atlantic ◽

North Atlantic Ocean ◽

Holocene Climate ◽

Nordic Seas ◽

The North ◽

Climate Evolution ◽

The North Atlantic

Download Full-text

Conductors of the current variations of the sea-surface temperature of the North Atlantic

Океанология ◽

10.31857/s0030-1574596895-902 ◽

2019 ◽

Vol 59 (6) ◽

pp. 895-902

Author(s):

N. V. Vakulenko ◽

D. M. Sonechkin

Keyword(s):

North Atlantic ◽

Rotation Axis ◽

Heat Content ◽

Sea Surface ◽

Short Time Period ◽

The North ◽

Time Period ◽

Climate Evolution ◽

To Come ◽

Short Time

It is generally accepted to believe that changes in the heat content of North Atlantic can be a source of surprises in the climate evolution, especially the climate of Europe. The RAPID program providing monitoring of this heat content serves to investigate this problem. However, results of such monitoring cover still too short time period to come to any conclusion. In this regard, changes of the North Atlantics sea surface mean temperature which already is observed during a long enough period (from the middle of the 20-th century) is analyzed as an indirect characteristic of the heat content. Wavelets are used for this purpose. Three scales, which define temporal variability of this characteristic, are found: from two to four, from seven up to ten, and about twenty two years. It is assumed that sources of variations of the first two from the specified scales are wobbles of the Earths rotation axis, and the source of variations of the third scale is the Hale's cycle of heliomagnetic activity.

Download Full-text

A 5500-year oxygen isotope record of high arctic environmental change from southern Spitsbergen

The Holocene ◽

10.1177/0959683617715698 ◽

2017 ◽

Vol 27 (12) ◽

pp. 1948-1962 ◽

Cited By ~ 9

Author(s):

Laura Arppe ◽

Eija Kurki ◽

Matthew J Wooller ◽

Tomi P Luoto ◽

Marek Zajączkowski ◽

...

Keyword(s):

Oxygen Isotope ◽

North Atlantic ◽

Little Ice Age ◽

Isotope Composition ◽

High Arctic ◽

Oxygen Isotope Composition ◽

Ice Age ◽

Oxygen Isotope Record ◽

Isotope Record ◽

Climate Evolution

The oxygen isotope composition of chironomid head capsules in a sediment core spanning the past 5500 years from Lake Svartvatnet in southern Spitsbergen was used to reconstruct the oxygen isotope composition of lake water (δ18Olw) and local precipitation. The δ18Olw values display shifts from the baseline variability consistent with the timing of recognized historical climatic episodes, such as the Roman Warm Period, the Dark Ages Cold Period and the ‘Little Ice Age’. The highest values of the record, ca. 3‰ above modern δ18Olw values, occur at ca. 1900–1800 cal. yr BP. Three negative excursions increasing in intensity toward the present, at 3400–3200, 1250–1100, and 350–50 cal. yr BP, are tentatively linked to roughly synchronous episodes of increased glacier activity and general cold spells around the northern North Atlantic. Their manifestation in the Svartvatnet δ18Olw record not only testify to the sensitivity and potential of high Arctic lacustrine δ18Ochir records in tracking terrestrial climate evolution but also highlight nonlinear dynamics within the northern North Atlantic hydroclimatic system. The ‘Little Ice Age’ period at 350–50 cal. yr BP displays a remarkable 8–9‰ drop in δ18Olw values, construed to predominantly represent significantly decreased winter temperatures during a period of increased seasonal differences and extended sea ice cover inducing changes in moisture source regions.

Download Full-text

Non-linear Holocene climate evolution in the North Atlantic: a high-resolution, multi-proxy record of glacier activity and environmental change from Hvítárvatn, central Iceland

Quaternary Science Reviews ◽

10.1016/j.quascirev.2012.02.006 ◽

2012 ◽

Vol 39 ◽

pp. 14-25 ◽

Cited By ~ 70

Author(s):

Darren J. Larsen ◽

Gifford H. Miller ◽

Áslaug Geirsdóttir ◽

Sædís Ólafsdóttir

Keyword(s):

High Resolution ◽

Environmental Change ◽

North Atlantic ◽

Holocene Climate ◽

Proxy Record ◽

The North ◽

Non Linear ◽

Climate Evolution ◽

The North Atlantic

Download Full-text

Consistency of the multi-model CMIP5/PMIP3-past1000 ensemble

Climate of the Past ◽

10.5194/cp-9-2471-2013 ◽

2013 ◽

Vol 9 (6) ◽

pp. 2471-2487 ◽

Cited By ~ 42

Author(s):

O. Bothe ◽

J. H. Jungclaus ◽

D. Zanchettin

Keyword(s):

North Atlantic ◽

North Pacific ◽

Surface Air Temperature ◽

Internal Variability ◽

Temperature Data ◽

Model Ensemble ◽

Single Model ◽

Ensemble Simulations ◽

The Pacific ◽

Climate Evolution

Abstract. We present an assessment of the probabilistic and climatological consistency of the CMIP5/PMIP3 ensemble simulations for the last millennium relative to proxy-based reconstructions under the paradigm of a statistically indistinguishable ensemble. We evaluate whether simulations and reconstructions are compatible realizations of the unknown past climate evolution. A lack of consistency is diagnosed in surface air temperature data for the Pacific, European and North Atlantic regions. On the other hand, indications are found that temperature signals partially agree in the western tropical Pacific, the subtropical North Pacific and the South Atlantic. Deviations from consistency may change between sub-periods, and they may include pronounced opposite biases in different sub-periods. These distributional inconsistencies originate mainly from differences in multi-centennial to millennial trends. Since the data uncertainties are only weakly constrained, the frequently too wide ensemble distributions prevent the formal rejection of consistency of the simulation ensemble. The presented multi-model ensemble consistency assessment gives results very similar to a previously discussed single-model ensemble suggesting that structural and parametric uncertainties do not exceed forcing and internal variability uncertainties.

Download Full-text