scholarly journals Glacier maxima in Baffin Bay during the Medieval Warm Period coeval with Norse settlement

2015 ◽  
Vol 1 (11) ◽  
pp. e1500806 ◽  
Author(s):  
Nicolás E. Young ◽  
Avriel D. Schweinsberg ◽  
Jason P. Briner ◽  
Joerg M. Schaefer

The climatic mechanisms driving the shift from the Medieval Warm Period (MWP) to the Little Ice Age (LIA) in the North Atlantic region are debated. We use cosmogenic beryllium-10 dating to develop a moraine chronology with century-scale resolution over the last millennium and show that alpine glaciers in Baffin Island and western Greenland were at or near their maximum LIA configurations during the proposed general timing of the MWP. Complimentary paleoclimate proxy data suggest that the western North Atlantic region remained cool, whereas the eastern North Atlantic region was comparatively warmer during the MWP—a dipole pattern compatible with a persistent positive phase of the North Atlantic Oscillation. These results demonstrate that over the last millennium, glaciers approached their eventual LIA maxima before what is considered the classic LIA in the Northern Hemisphere. Furthermore, a relatively cool western North Atlantic region during the MWP has implications for understanding Norse migration patterns during the MWP. Our results, paired with other regional climate records, point to nonclimatic factors as contributing to the Norse exodus from the western North Atlantic region.

The Holocene ◽  
2018 ◽  
Vol 29 (1) ◽  
pp. 85-96 ◽  
Author(s):  
Ioana Perșoiu ◽  
Aurel Perșoiu

We present here the first record of past flooding activity from the Carpathian Mountains, Eastern Europe, based on documentary evidence and sedimentary records along one of the main rivers draining this region (Someșul Mic River). Three periods of increased flood activity have occurred in Transylvania during the last millennium: the first at the beginning of the 10th century (the end of the Dark Ages Cold Period and beginning of the Medieval Warm Period (MWP)); the second at the end of the 16th and beginning of 17th century, during the cold Little Ice Age (LIA) and the third at the end of the 19th century. During the early MWP, generally wet summers resulted in a high incidence of floods and/or high discharges, while the cluster of floods at the end of 16th and beginning of the 17th centuries occurred mostly at flash floods generated during heavy summer thunderstorms. Increasing winter temperatures and spring precipitations probably caused the high incidence of floods at the end of the 19th century. The predominantly wet conditions during the MWP are likely to have resulted from northward penetration of Mediterranean cyclones during a (mostly) positive phase of the North Atlantic Oscillation (NAO), while wet conditions during the LIA arose as a combination of increases in local storminess and moisture transport from the North Atlantic along more southerly positioned westerlies associated with a negative phase of the NAO.


1998 ◽  
Vol 1 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Tom Amorosi ◽  
Paul C. Buckland ◽  
Kevin J. Edwards ◽  
Ingrid Mainland ◽  
Tom H. McGovern ◽  
...  

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
John Crossley ◽  
Christopher A. Skilbeck

This article describes a study of Tripleurospermum maritimum (L.) W.D.J. Koch and T. inodorum (L.) Sch. Bip. (Asteraceae) in the Orkney Islands (v.c.111), the results of which suggest that intermediates between these taxa may be rather common, and that T. maritimum subsp. nigriceps and subsp. maritimum are both involved, the former more frequently. Obviously this results in a complex taxonomic situation, evidently not confined to Orkney in the far north. Key identifying characters of the taxa are systematically examined and guidance offered on determining hybrids using a population level approach. The taxonomic complexities of these northern populations are discussed, with regard in particular to the identity of T. inodorum occurring there and the place of T. maritimum subsp. nigrescens in the forms and subspecies of T. maritimum found in the north Atlantic region.


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