scholarly journals On the cause of abrupt vegetation collapse in North Africa during the Holocene: Climate variability vs. vegetation feedback

2006 ◽  
Vol 33 (22) ◽  
Author(s):  
Zhengyu Liu ◽  
Yi Wang ◽  
Robert Gallimore ◽  
Michael Notaro ◽  
I. Colin Prentice
Keyword(s):  
Climate Variability ◽  
North Africa ◽  
Holocene Climate ◽  
Vegetation Feedback ◽  
The Holocene

scholarly journals Holocene climate variability in north-eastern Italy: potential influence of the NAO and solar activity recorded by speleothem data

2012 ◽  
Vol 8 (4) ◽  
pp. 1367-1383 ◽  
Author(s):  
D. Scholz ◽  
S. Frisia ◽  
A. Borsato ◽  
C. Spötl ◽  
J. Fohlmeister ◽  
...  
Keyword(s):  
Solar Activity ◽  
Stable Isotope ◽  
Climate Variability ◽  
Regional Climate ◽  
Regional Scale ◽  
Holocene Climate ◽  
Winter Climate ◽  
The Holocene ◽  
North Eastern ◽  
The Mediterranean

Abstract. Here we present high-resolution stable isotope and lamina thickness profiles as well as radiocarbon data for the Holocene stalagmite ER 76 from Grotta di Ernesto (north-eastern Italy), which was dated by combined U-series dating and lamina counting. ER 76 grew between 8 ka (thousands of years before 2000 AD) and today, with a hiatus from 2.6 to 0.4 ka. Data from nine meteorological stations in Trentino show a significant influence of the North Atlantic Oscillation (NAO) on winter temperature and precipitation in the cave region. Spectral analysis of the stable isotope signals of ER 76 reveals significant peaks at periods of 110, 60–70, 40–50, 32–37 and around 25 a. Except for the cycle between 32 and 37 a all periodicities have corresponding peaks in power spectra of solar variability, and the 25-a cycle may correspond to NAO variability. This suggests that climate variability in northern Italy was influenced by both solar activity and the NAO during the Holocene. Six periods of warm winter climate in the cave region were identified. These are centred at 7.9, 7.4, 6.5, 5.5, 4.9 and 3.7 ka, and their duration ranges from 100 to 400 a. The two oldest warm phases coincide with the deposition of sapropel S1 in the Mediterranean Sea indicating that the climate in the cave region was influenced by this prominent pluvial phase in the Mediterranean area. For the younger warm phases it is difficult to establish a supra-regional climate pattern, and some of them may, thus, reflect regional climate variability. This highlights the complexity of regional and supra-regional scale Holocene climate patterns.

scholarly journals Holocene climate variability in North-Eastern Italy: potential influence of the NAO and solar activity recorded by speleothem data

2012 ◽  
Vol 8 (2) ◽  
pp. 909-952 ◽  
Author(s):  
D. Scholz ◽  
S. Frisia ◽  
A. Borsato ◽  
C. Spötl ◽  
J. Fohlmeister ◽  
...  
Keyword(s):  
Solar Activity ◽  
Stable Isotope ◽  
Climate Variability ◽  
Regional Climate ◽  
Regional Scale ◽  
Holocene Climate ◽  
Winter Climate ◽  
The Holocene ◽  
North Eastern ◽  
The Mediterranean

Abstract. Here we present high-resolution stable isotope and lamina thickness profiles as well as radiocarbon data for the Holocene stalagmite ER 76 from Grotta di Ernesto (North-Eastern Italy), which was dated by combined U-series dating and lamina counting. ER 76 grew between 8 ka (thousands of years before 2000 AD) and today, with a hiatus from 2.6 to 0.4 ka. Data from nine meteorological stations show a significant influence of the North Atlantic Oscillation (NAO) on winter precipitation in the cave region. Spectral analysis of the stable isotope signals of ER 76 reveals significant peaks at periods of 110, 60–70, 40–50, 32–37 and around 25 a. Except for the cycle between 32 and 37 a all periodicities have corresponding peaks in power spectra of solar variability, and the 25-a cycle may correspond to NAO variability. This suggests that climate variability in Northern Italy was influenced by both solar activity and the NAO during the Holocene. Six periods of warm winter climate in the cave region were identified. These are centred at 7.9, 7.4, 6.5, 5.5, 4.9 and 3.7 ka, and their duration ranges from 100 to 400 a. The two oldest warm phases coincide with the deposition of sapropel S1 in the Mediterranean Sea indicating that the climate in the cave region was influenced by this prominent pluvial phase in the Mediterranean area. For the younger warm phases it is difficult to establish a supra-regional climate pattern, and some of them may, thus, reflect regional climate variability. This highlights the complexity of regional and supra-regional scale Holocene climate patterns.

scholarly journals Environmental responses of the Northeast Antarctic Peninsula to the Holocene climate variability

2016 ◽  
Vol 31 (1) ◽  
pp. 131-147 ◽  
Author(s):  
Loïc Barbara ◽  
Xavier Crosta ◽  
Amy Leventer ◽  
Sabine Schmidt ◽  
Johan Etourneau ◽  
...  
Keyword(s):  
Climate Variability ◽  
Antarctic Peninsula ◽  
Holocene Climate ◽  
The Holocene ◽  
Environmental Responses

scholarly journals The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere–sea-ice–ocean model

2013 ◽  
Vol 9 (4) ◽  
pp. 1629-1643 ◽  
Author(s):  
M. Blaschek ◽  
H. Renssen
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Surface Cooling ◽  
Holocene Climate ◽  
Nordic Seas ◽  
The Holocene ◽  
Holocene Thermal Maximum ◽  
Thermal Maximum ◽  
The Impact

Abstract. The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene thermal maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveals a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from the previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in an ocean surface cooling of up to 2 K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of the early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come.

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