A Regional Approach to the Medieval Warm Period and the Little Ice Age

Ljungqvist, Fredrik Charpentier

doi:10.5772/9798

Cited by 14 publications

(29 citation statements)

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“…The warmer climate of the time [cf. Ljungqvist, 2010] increased water temperatures and probably stimulated larger primary production during calm summers. In combination with rising anthropogenic nutrient loads, this may have favored hypoxia in the Baltic Sea.…”

Section: Discussionmentioning

confidence: 99%

Salinity and hypoxia in the Baltic Sea since A.D. 1500

Hansson

Gustafsson

2011

J. Geophys. Res.

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[1] Over the past century, large salinity variability and deteriorating oxygen conditions have been observed in the Baltic Sea. These long-term changes were investigated in the central Baltic Sea using an ocean climate model with meteorological forcing based on seasonal temperature and pressure reconstructions covering the period 1500-1995. The results indicate that the salinity has slowly increased by 0.5 salinity units since 1500, peaking in the middle eighteenth century. Oxygen concentration is negatively correlated with salinity in the major part of the water column, indicating improved ventilation during a fresher state of the Baltic Sea. It is suggested that anoxic conditions have occurred in the deep water several times per century since 1500. However, since the middle twentieth century, increased oxygen consumption that is most likely the effect of anthropogenic nutrient release has resulted in a persistent oxygen deficiency in the water below 125 m. Within the limitations of our model formulation we suggest that the contemporary severe oxygen conditions are unprecedented since 1500.

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Section: Discussionmentioning

confidence: 99%

Salinity and hypoxia in the Baltic Sea since A.D. 1500

Hansson

Gustafsson

2011

J. Geophys. Res.

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“…There is growing evidence that the Little Ice Age occurred throughout the Northern Hemisphere (Ljungqvist, 2009(Ljungqvist, , 2010 and is distinctly seen as taking place during the last three to four centuries with a termination at ∼ 1900 AD (Grove, 2001). Other studies, however, mention that the LIA started somewhere between ∼ 1300 and 1400 AD (Fricke et al, 1995;Mauquoy et al, 2002;Moberg et al, 2005;Cage and Austin, 2010;Ljungqvist, 2010;Miller et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

“…Other studies, however, mention that the LIA started somewhere between ∼ 1300 and 1400 AD (Fricke et al, 1995;Mauquoy et al, 2002;Moberg et al, 2005;Cage and Austin, 2010;Ljungqvist, 2010;Miller et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

The Little Ice Age: evidence from a sediment record in Gullmar Fjord, Swedish west coast

2013

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We discuss the climatic and environmental changes during the last millennium in NE Europe based on a ca. 8-m long high-resolved and well-dated marine sediment record from the deepest basin of Gullmar Fjord (SW Sweden). According to the ²¹⁰Pb- and ¹⁴C-datings, the record includes the period of the late Holocene characterised by anomalously cold summers and well-known as the Little Ice Age (LIA). Using benthic foraminiferal stratigraphy, lithology, bulk sediment geochemistry and stable carbon isotopes we reconstruct various phases of the cold period, identify its timing in the study area and discuss the land–sea interactions occurring during that time. The onset of the LIA is indicated by an increase in cold-water foraminiferal species Adercotryma glomerata at ~ 1350 AD The first phase of the LIA was characterised by a stormy climate and higher productivity, which is indicated by a foraminiferal unit of Nonionella iridea and Cassidulina laevigata. Maximum abundances of N. iridea probably mirror a short and abrupt warming event at ~ 1600 AD. It is likely that due to land use changes in the second part of the LIA there was an increased input of terrestrial organic matter to the fjord, which is indicated by lighter δ¹³C values and an increase of detritivorous and omnivorous species such as Textularia earlandi and Eggerelloides scaber. The climate deterioration during the climax of the LIA (1675–1704 AD), as suggested by the increase of agglutinated species, presence of Hyalinea balthica, and a decline of N. iridea may have driven the decline in primary productivity during this time period

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“…70 (E) Reconstructed Northern Siberian and Chinese summer temperatures. 51 (F) and (G) Historical changes in the mass concentration ratios among different organic marker compounds measured in the Ushkovsky ice core. 11,47 3-HGA and MBTCA are higher-204 generation products.…”

Section: Environmental Science and Technology Lettersmentioning

confidence: 99%

Historical Trends of Biogenic SOA Tracers in an Ice Core from Kamchatka Peninsula

Kawamura

Seki

et al. 2016

Environ. Sci. Technol. Lett.

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Biogenic secondary organic aerosol (SOA) is ubiquitous in the Earth's atmosphere, influencing climate and air quality. However, the historical trend of biogenic SOA is not well known. Here, we report for the first time the major isoprene-and monoterpene-derived SOA tracers preserved in an ice core from the Kamchatka Peninsula. Significant variations are recorded during the past 300 years with lower concentrations in the early-to-middle 19th century and higher concentrations in the preindustrial period and the present day. We discovered that isoprene SOA tracers were more abundant in the preindustrial period than the present day, while monoterpene SOA tracers stay almost unchanged. The causes of the observed variability are complex, depending on atmospheric circulation, changes in emissions, and other factors such as tropospheric oxidative capacity. Our data presents an unprecedented opportunity to shed light on the formation, evolution, and fate of atmospheric aerosols and to constrain the uncertainties associated with modeling their atmospheric concentrations. ■ INTRODUCTION Palaeoclimate archives containing annual layers (e.g., ice cores, tree rings, speleothems, and coral reefs) have played a central role in reconstructing decadal-scale climatic oscillation of the past. 1 This insight has proved an invaluable tool to constrain climate model projections of future climate change by validating model hindcasts. Similarly, analysis of particles preserved in ice cores provides an unprecedented opportunity to elucidate the distribution, concentration, size distribution, and even chemical composition of atmospheric aerosols in the past. Such data would allow us to deduce the influence of aerosol radiative forcing on past climate change. Previously, aerosol particles preserved in high altitudinal or high latitudinal ice cores have been examined for inorganic species (e.g., sulfate), black carbon, and organic species such as polycyclic aromatic hydrocarbons, carboxylic acids, biomass burning tracers, and humic-like substances. 2−7 To date, little was known about the historical trends of secondary organic aerosols at a molecular level. 3,8 Here, we present the findings of the analysis of ice cores for evidence of organic compounds formed from biogenic trace gases. Terrestrial vegetation emits large quantities (∼1 Pg C y −1) of biogenic volatile organic compounds (BVOCs), including reactive species such as isoprene and monoterpenes, to the atmosphere. 9 The role of their atmospheric reactions in 50 governing the production and loss of tropospheric ozone is 51 well studied and relatively well understood, but BVOC 52 oxidation has also been shown to lead to aerosol 53 formation. 10−12 Organic particles formed by the photooxidation 54 of BVOCs are considered "secondary" organic aerosols (SOA) 55 and are believed to be more abundant than directly emitted 56 "primary" organic aerosols (POA) in the Earth's atmos-57 phere. 11,13−16 It is believed that SOA could be a significant 58 source of new nanoscale particles, especially in...

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A Regional Approach to the Medieval Warm Period and the Little Ice Age

Cited by 14 publications

References 104 publications

Salinity and hypoxia in the Baltic Sea since A.D. 1500

Salinity and hypoxia in the Baltic Sea since A.D. 1500

The Little Ice Age: evidence from a sediment record in Gullmar Fjord, Swedish west coast

Historical Trends of Biogenic SOA Tracers in an Ice Core from Kamchatka Peninsula

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