A composite annual-resolution stalagmite record of North Atlantic climate over the last three millennia

Abstract

Annually laminated stalagmites can be used to construct a precise chronology, and variations in laminae thickness provide an annual growth-rate record that can be used as a proxy for past climate and environmental change. Here, we present and analyse the first composite speleothem annual growth-rate record based on five stalagmites from the same cave system in northwest Scotland, where precipitation is sensitive to North Atlantic climate variability and the winter North Atlantic Oscillation (NAO). Our 3000-year record confirms persistently low growth-rates, reflective of positive NAO states, during the Medieval Climate Anomaly (MCA). Another persistently low growth period occurring at 290-550 CE coincides with the European Migration Period, and a subsequent period of sustained fast growth-rate (negative NAO) from 600-900 AD provides the climate context for the Viking Age in northern and western Europe.

Centennial-scale vegetation and North Atlantic Oscillation changes during the Late Holocene in the southern Iberia

“…Our results agree with previous studies in the area and arid conditions at this time are well documented in changes in paleoecological and geochemical proxies in the Laguna de la Mula, Sierra Nevada (Jiménez- Moreno et al, 2013b) Moreno et al, 2013b). NAO reconstructions show the most negative phases during this period (Olsen et al, 2012;Baker et al, 2015;Fig. 4), which could explain high winter precipitation, the main source of moisture in this area.…”

“…Previous studies show overall arid conditions and persistently positive NAO (low winter precipitation) during this time, supporting our 20 results. For example, tree-ring and speleothem analyses from Morocco and Scotland (Trouet et al, 2009;Wassenburg et al, 2013;Baker et al, 2015) and a multiproxy geochemical record from a small lake in Greenland (Olsen et al, 2012) all show a strong correlation among different paleoclimate proxies with positive NAO during that time. This also agrees with more regional marine and terrestrial studies from the Iberian Peninsula.…”

“…In the last years a variety of multiproxy records have been used for the reconstruction of past NAO conditions (e.g. D ' Arrigo et al, 1993;Trouet et al, 2009;Olsen et al, 2012;Baker et al, 2015). These show that positive NAO conditions triggered a decrease in precipitation in the western Mediterranean area, while wetter conditions occurred during negative NAO phases.…”

Variations in the difference between mean sea level measured either side of Cape Hatteras and their relation to the North Atlantic Oscillation

“…Comparisons between the Luterbacher et al record and other reconstructions, with a focus on the wintertime NAO for the last millennium, have been made by Trouet et al (2009), Pinto and Raible (2012) and Ortega et al (2015) (see also Lehner et al 2012 andBaker et al 2015). For example, Figure 3 of Pinto and Rable (2012) demonstrates the close agreement between versions of the wintertime index computed by different groups for the late 19 th century onwards, with significant differences more apparent before that time.…”

Climate control on late Holocene high-energy sedimentation along coasts of the northeastern Atlantic Ocean

“…Several reconstructions of lowto high-frequency changes in the NAO index are available for the late Holocene to historical periods, with differences in temporal coverage and resolution ( Fig. 7E; Baker et al, 2015;Olsen et al, 2012;Ortega et al, 2015;Proctor et al, 2000;Trouet et al, 2009). The EA/WR atmospheric circulation pattern has received less attention, with a focus mostly on its impact on temperature and precipitation in western Europe and in the Mediterranean region (Ionita, 2014;Krichak and Alpert, 2005;Lim, 2015, and references therein).…”