Short-term Climatic Events Research Articles

Effects of physical forcing on short-term plankton dynamics in a narrow coral reef lagoon (Ouano, New Caledonia): a two-week high-frequency study

Abstract The response of plankton communities to short-term climatic events was studied in a narrow coral reef lagoon representative of the channel-type lagoons of the high islands of the tropical Pacific. Phyto- and zooplankton data (abundance and taxonomic composition) were sampled at high frequencies for 2 weeks in April–May 2017 under various tidal conditions and combined with environmental and physical measurements and modeling hydrodynamic products. The short-term external events (wind, waves and rain) that occurred caused changes in the circulation patterns and increased nutrient concentrations in the lagoon. The plankton reacted quickly to this enrichment, with an increase in chlorophyll a and the rapid development of a microphytoplankton community dominated by diatoms, and of opportunistic herbivorous zooplankton (tintinnids, appendicularians). Zooplankton composition and distribution were strongly modulated by the circulation patterns through advection and mixing. Our results show that the tidal and diel components of the temporal variability of planktonic groups were blurred by sporadic event components (i.e. wind, wave and rainfall events). Environmental and biological responses to these external physical forcings occurred at lagoon scale in this channel-like lagoon, unlike what is observed in larger lagoons (such as the southern lagoons of New Caledonia) where spatial variability is much higher.

Orbital-paced silicate weathering intensity and climate evolution across the Eocene-Oligocene transition in the southeastern margin of the Tibetan Plateau

The Eocene-Oligocene transition (EOT, ∼33.9 Ma), a period of dramatic global cooling marking the onset of the Antarctic ice sheet. However, paleoclimatic reconstructions indicate a notable spatial heterogeneity in both the marine and terrestrial realms. While limited temporal resolution terrestrial records have hindered the precise understanding of short-term climate events and orbital-scale changes during this transition. Here, we present a chemical weathering data sequence from a fluvial-lacustrine deposition from Lühe Basin, which is located at southeastern margin of the Tibetan Plateau. Based on the radioisotope, paleomagnetic and 405 kyr orbital tuning of the elemental datasets, the deposition age of Lühe Basin is dated to ∼35.5–25.5 Ma. Two weakening stages of the weathering intensity are detected around Eocene-Oligocene boundary: 34.1 to 33.9 Ma and 33.8 to 33.6 Ma, which are temporally equivalent to the two global main climatic steps of EOT (EOT-1 and Oi-1). We find the chemical weathering intensity sequence paced the 1.2 Myr obliquity amplitude modulation and 405 kyr long-eccentricity cycles. Notably, the minima of 1.2 Myr obliquity amplitude and 405 kyr eccentricity are synchronous with the Oil-1 event. These patterns highlight the role of orbital forcing in shaping the cooling trend across the EOT and may trigger Antarctic glaciation.

Assessment of climate extremes at the regional scale during the last millennium using an annually resolved stalagmite record

In public awareness, extraordinary floods, heat-waves, or drought episodes rank amongst the most tangible indications of a changing climate. Forecasting the magnitude of such extreme events at regional and local scales is a major challenge. Development of reliable small-scale climate models requires testing against past climate records, but these are often incomplete, or cover only partial aspects in a spectrum of environmental parameters, e.g., due to seasonal bias as it is the case for tree-ring records. Here, we study a stalagmite from the “Kleine Teufelshöhle” (KTH) in the Franconian karst (Germany) to obtain independent information on local climate conditions at multi-annual to multi-decadal time scales. Radiocarbon and 230Th/U dating provide constraints for linear growth models, which were then successfully refined by correlating high spatial resolution O isotope data for the KTH stalagmite with a published regional tree-ring width record at annual resolution for the past 1000 years. Besides the availability of the tree-ring record, the KTH site offers the additional advantage that direct comparison between tree-ring and speleothem climate proxies with historical documents is possible due to the proximity of the speleothem and tree-ring sites to the former “Free imperial city” of Nuremberg. Historical documents provide precisely dated records of extreme events, in particular for destructive floods. Higher O isotope values in the stalagmite characterize the “Litte Ice Age" (LIA), an interval coinciding with frequent and devastating floods, sometimes associated with river blockage related to accumulation of ice rafts. Prior to approximately 1500 Common Era (CE), O isotope values were generally lower and only show minor overlap with historical flooding accounts. Conversely, some known drought events for Central Europe as well as the climatic influence of large-volume volcanic eruptions with hemispheric to global impact may be recorded in the speleothem as negative excursions in speleothem O isotopic values. The correlated tree-ring and speleothem data for the first time provide a complementary paleohydrology record that is uniquely suited to resolve extreme short-term climate events at the regional scale.

An Environmental and Climate History of the Roman Expansion in Italy

Abstract A first synthesis of available data for the period of Rome’s expansion in Italy (about 400–29 b.c.e.) shows the role of climate and environment in early Roman imperialism. Although global indices suggest a warmer phase with relatively few short-term climate events occuring around the same time as the expansion, local data emphasize the highly variable timing and expression of these trends. This variability casts doubt on ideas of a unitary, historically consequential “Roman Warm Period.” The historical importance of climate and environment to socioeconomic development merits emphasis, but should be understood in terms of evolving, contingent forms of resilience and risk-mitigating behavior by Italian communities during Roman expansion.

Influence of monsoon anomalies on intra-annual density fluctuations of Chinese pine in the Loess Plateau

In the past few decades, the East Asian summer monsoon (EASM) has experienced an unprecedented weakening, exacerbating drought in northern China, especially in the monsoon margin area. Improving our understanding of monsoon variability will benefit agricultural production, ecological construction, and disaster management. Tree-ring is widely used as proxy data for extending the monsoon history. However, in the East Asian monsoon margin, the tree-ring width were mostly formed before the rainy season, thus may have limited ability to indicate the monsoon variability. Intra-annual density fluctuations (IADFs) can provide higher resolution information on tree growth as well as evidence of short-term climate events. Here, we used Chinese pine (Pinus tabuliformis Carr.) samples from the eastern edge of the Chinese Loess Plateau (CLP), where the climate is deeply affected by monsoon, to investigate the response of tree growth and IADFs frequency to climate variation. We show that tree-ring width and IADFs record significantly different climatic signals. The former was mainly affected by moisture conditions at the end of the previous growing season and the current spring. While the latter was common in years when severe droughts occurred in June and July, especially in June. This period coincides with the onset of the EASM, so we further analyzed the relationship between IADFs frequency and the rainy season. Both correlation analysis and the GAM model suggest that the frequent occurrence of IADFs may be related to the late start of the monsoon rainy season, meaning that we have found a new indicator in tree-ring records that can capture monsoon anomalies. Our results provide further insight into drought variation in the eastern CLP, which also implicates the Asian summer monsoon dynamic.

Short-term paleogeographic reorganizations and climate events shaped diversification of North American freshwater gastropods over deep time

What controls species diversity and diversification is one of the major questions in evolutionary biology and paleontology. Previous studies have addressed this issue based on various plant and animal groups, geographic regions, and time intervals. However, as most previous research focused on terrestrial or marine ecosystems, our understanding of the controls on diversification of biota (and particularly invertebrates) in freshwater environments in deep time is still limited. Here, we infer diversification rates of North American freshwater gastropods from the Late Triassic to the Pleistocene and explore potential links between shifts in speciation and extinction and major changes in paleogeography, climate, and biotic interactions. We found that variation in the speciation rate is best explained by changes in continental fragmentation, with rate shifts coinciding with major paleogeographic reorganizations in the Mesozoic, in particular the retreat of the Sundance Sea and subsequent development of the Bighorn wetland and the advance of the Western Interior Seaway. Climatic events in the Cenozoic (Middle Eocene Climate Optimum, Miocene Climate Optimum) variably coincide with shifts in speciation and extinction as well, but no significant long-term association could be detected. Similarly, no influence of diversity dependence was found across the entire time frame of ~ 214 Myr. Our results indicate that short-term climatic events and paleogeographic changes are relevant to the diversification of continental freshwater biota, while long-term trends have limited effect.

Sequence stratigraphy and microplankton palaeoenvironmental dynamics across the Jurassic–Cretaceous transition in the Canadian Arctic

ABSTRACTThe Jurassic to Cretaceous strata exposed in the Rollrock Section, Sverdrup Basin, Arctic Canada, represent one of the northernmost continuous outcrops spanning this poorly understood transition. The Oxfordian–Valanginian mudstones of the Rollrock Section were deposited in a shallow marine environment and, as such, provide the ideal lithology to investigate the response of high latitude dinoflagellate cyst populations to the frequent environmental perturbations of this time. Using a multivariate statistical approach, distinct palaeoecologically significant groups are identified and directly linked to time and palaeoenvironments, allowing for the reconstruction of underlying long term palaeoenvironmental trends. These palaeoenvironmental trends are identified to be driven by sequence stratigraphic cycles. For the first time, fourth order sequences are recorded from this pivotal period in the Sverdrup Basin and reveal an additional level of short term climatic events that complicate the identification of long term trends. The relationship existing between marine phytoplankton and climate is utilised to decipher the interplay of long-term and short-term climate fluctuations, distinguishing them from evolutionary trends. Two groups of dinoflagellate cysts, identified by process morphology, are recorded to act as environmental proxies. High percentages of proximochorate dinoflagellate cysts, such as Trichodinium erinaceoides, indicate more proximal, high energy, nutrient rich conditions and are dominant in fourth order transgressive systems tracts. High percentages of chorate dinoflagellate cysts, such as Oligosphaeridium complex, signify distal, low energy, nutrient depleted conditions and are dominant in fourth order highstand systems tracts.

A high-resolution, 1250-year long drought record from Ea Tyn Lake, Central Highlands of Việt Nam

An understanding of past climatic variability at regional to local scales is mandatory for a proper evaluation of current and potential future repercussions from global climate change. The Southeast Asian tropics remain severely under-represented in paleoenvironmental and paleoclimatic reconstructions, although a few recent paleoclimate studies evaluated the variability, position and strength of the main Asian monsoon systems at different timescales from modern records to the last 15,000 years. Comparable data from Việt Nam, however, are scarce although Việt Nam and its Central Highlands are critically located at the intersection of the East Asian Summer Monsoon and the Indian Summer Monsoon with highly important socio-ecological consequences from changes in the climate system. This study presents a high-resolution sedimentary climate record from Ea Tyn Lake in Việt Nam’s Central Highlands covering the last 1250 years. Using geochemical and sedimentological proxies and principal component analysis, we reconstructed at least 12 drought events, some of which appear to be of supraregional significance as they coincide with historically documented droughts in India, China, and Cambodia. Beyond tracking short-term climate events, the Rb/Sr elemental ratio along the Ea Tyn Lake sediment sequence reflects long-term monsoon variability throughout the last millenium, which was previously only reconstructed via δ18O speleothem records from China and India. Our Ea Tyn Lake record shows that the East Asian Summer Monsoon was relatively strong between ~1000 and 1350 cal CE and weaker between 1350 and 1850 cal CE, followed by renewed intensification after ~1850 cal CE.

Early Growth Responses of Larix kaempferi (Lamb.) Carr. Seedling to Short-Term Extreme Climate Events in Summer

Extreme climate events such as heat waves, drought, and heavy rainfall are occurring more frequently and are more intense due to ongoing climate change. This study evaluated the early growth performance of one-year-old Larix kaempferi (Lamb.) Carr. seedlings under open-field extreme climate conditions including experimental warming and different precipitation regimes. We recorded the survival rate, root collar diameter, height, biomass, shoot-to-root ratio, and seedling quality index using nine treatments (three temperature levels, i.e., control, warming by 3 °C and by 6 °C, × three precipitation levels, i.e., control, drought, and heavy rainfall) in July and August 2020. The survival rate of seedlings did not differ between treatments, showing high values exceeding 94% across treatments. The measured shoot height was largest under warming by 3 °C and high rainfall, indicating that moderate warming increased seedling height growth in a moist environment. Heavy rainfall decreased stem volume by 21% and 25% under control and warming by 6 °C treatments, respectively. However, drought manipulation using rain-out shelters did not decrease the growth performance. Overall, extreme climate events did not affect the survival rate, biomass, shoot-to-root ratio, and seedling quality index of L. kaempferi. We thus conclude that, regarding growth responses, L. kaempferi seedlings may be resistant to short-term extreme warming and drought events during summer.

Late Holocene Hydro-Climate Variability in the Eastern Mediterranean: A Spatial Multi-Proxy Approach

A total of thirteen (13) paleoclimatic coastal and hinterland archives of the broader eastern Mediterranean region were collected and examined statistically in search of underlying trends for the period 2800 to 200 BP. For each archive, a proxy record representative of hydro-climatic changes was selected, normalized using z-factors to facilitate intercomparison, and analyzed statistically. Multivariate statistical analysis was performed using a clustering analysis (HCA) and dimension reduction (PCA), which led to groupings of similar records temporally, and allowed the identification of spatially underlying modes of variability. Two main modes of variability were identified, further supporting complex trajectories of paleoclimatic evolution in the region. The first mode was identified for sites presenting a trend from a wetter to an overall drier phase, with respective changes at major phase shifts at 1400 BP and 1100 BP. All sites were from the southern and northern Balkan region, as well as southwestern Turkey. A contrasting dry to wet trend was identified for a site in the Peloponnese (Greece) and the Levant, with a major phase shift at around 750 BP. The inclusion of different proxies from very different environmental settings and the 200-year window has complicated the connection of established short-term climatic events to the study’s findings.

How long and how strong must a climatic anomaly be in order to evoke a social transformation? Historical and contemporaneous case studies

In recent years, scholarly interest in the nexus between climate change and human societies has risen dramatically, and many researchers from different disciplines have begun studying the possible effects of climate change and climate anomalies on past and present societies. In this article, we join this lively debate, seeking to extend it by raising, and providing possible answers to, two fundamental questions: what type of climatic anomalies can undermine social stability? What duration and intensity are necessary to instigate structural change? When attempting to answer these questions, researchers tend to view short-term climatic events, such as storms or mudslides, as “unusual” events that instigate an “unusual” reality for temporary, and measurable, time periods. We argue, instead, that gradual and more “usual” climatic events, such as prolonged droughts or extended periods of untimely rains, impact societies in a more profound and “extraordinary” manner, and it is here that our paper meets the theme of the extraordinary and the usual, the axes of the current collection of essays. Based on qualitative examination of collapse periods in western Asia and northern China during the eleventh and early twelfth centuries, and a high-resolution re-examination of the crisis in Mali at the beginning of 2010, we argue that extended climate anomalies that cause decreases in the amount of available food are the anomalies that most affect the fate of human civilizations. While people can cope with short-term climate anomalies that cause periodical food crises, lasting a year or two, extended climate anomalies that affect the availability of food, like droughts, cold spells or untimely rains, can have disastrous, long-term effects: they accelerate decisive processes, push people to migrate outside their regions of residence, increase violence and religious extremism, and, ultimately, lead to structural changes in the societies that are affected by the crises.

Marine heat waves differentially affect functioning of native (Ostrea edulis) and invasive (Crassostrea [Magallana] gigas) oysters in tidal pools

The frequency and duration of short-term extreme climatic events, such as marine heat waves (MHWs), are increasing worldwide. The rapid onset of MHWs can lead to short-term stress responses in organisms that may have lethal or sub-lethal effects. In addition, increased temperature variability and extremes are predicted to favour and facilitate the spread of non-native species, altering rates of key ecosystem processes and functions. It is possible, however, that compensatory mechanisms, such as increased feeding rates, may enable the maintenance of metabolic functioning and prevent detrimental temperature effects. Using a mesocosm-based approach, we experimentally tested for the effects of MHWs in tidal pools on the mortality, individual length, width and biomass, and respiration rates for both a native oyster, Ostrea edulis, and invasive oyster, Magallana gigas, with or without food supply. No mortality was recorded for either O. edulis or M. gigas for the duration of the four week experiment. Increases in length were greater in O. edulis compared to M. gigas but were not affected by temperature or food supply. Increases in width, however, did not differ between species but were reduced overall in heat wave treatments regardless of food supply. O. edulis gained more biomass than M. gigas in ambient treatments regardless of food supply but, in heat wave treatments, only gained greater biomass than M. gigas at additional levels of food supply. Respiration rates did not reflect changes in temperature or food supply in either species but differed through time, with greater rates post-heat wave in all treatments. Thermal responses of O. edulis and M. gigas to MHWs thus appear to be context dependent and, if food supply is sufficient, O. edulis may be able to maintain its presence in the intertidal. The ability of M. gigas to remain unaffected by fluctuating environmental conditions, however, suggests future resilience of invasive populations to climatic extremes that may result in competitive exclusion and a further decline in native oyster populations. This information is critical for developing effective management plans to ensure the sustainability of natural oyster populations whilst maintaining key ecosystem functioning.

Palaeoecological response to Greenlandian (Early Holocene) climatic changes: Insight from an abandoned-channel sequence of the Meuse River at Autrecourt-et-Pourron (Ardennes, France)

A Greenlandian (Early Holocene) palaeochannel of the Meuse River is described from Autrecourt-et-Pourron in the Ardennes region of northern France. During the Younger Dryas, fluvial deposits represent a high-energy, sinuous palaeochannel, but at the onset of the Holocene, progressive channel abandonment resulted in the establishment of a low-energy meandering river system. Well-dated studies using palynology, carpology, malacology and geomorphology reveal a Greenlandian succession of changes in fluvial dynamics and vegetation. Between 11,700 and 11,400 cal yr BP, warmer temperatures led to the development of a birch community (Betula sp.) within an open grassland, dominated by herbaceous cold-adapted plants (Linum alpinum, Plantago montana, Artemisia sp., Juniperus sp.). Between 11,400 and 11,100 cal yr BP, the river and the vegetation dynamics reflected two short-term climate events. Around 11,400 cal yr BP, the palaeochannel became separated from the active channels of the Meuse River but remained dominated by waterlogged wetlands. This cold and wet phase represents the “Preboreal Oscillation” also referred as the “11.4 ka event”. Around 11,300 cal yr BP, the records suggest that fire frequency increased close to the channel, and may indicate a dry episode that reflects a sharp, short-lived rise in temperature. Between 11,100 and 10,700 cal yr BP (Late Preboreal phase), the channel received flood deposits again. Salix and helophytes developed while Populus colonised the riverbank. From 10,700 cal yr BP, at the beginning of the Boreal phase, the palaeochannel was finally abandoned and dense temperate woodland with Corylus avellana and Quercus spp. became established. Based on its high chronological resolution, Autrecourt-et-Pourron represents a key locality in north-western Europe to investigate environmental change in connection with Early Holocene short climate variations. In addition, the results highlight the valuable contribution of carpological analyses in improving the spatial resolution of reconstructions of vegetation cover.

Attitudes of urban residents towards environmental migration in Kenya and Vietnam

The displacement of people is an important consequence of climate change, as people may choose or be forced to migrate in response to adverse climate conditions or sudden-onset extreme climate events. Existing studies show that there is a consistently higher social acceptance of migrants fleeing political persecution or war than of economic migrants. Here we examine whether individuals in Vietnam and Kenya also extend the notion of deservingness to environmental migrants in the context of internal rural-to-urban migration, using original data from a choice-based conjoint survey experiment. We find that although residents in receiving areas view short-term climate events and long-term climate conditions as legitimate reasons to migrate, they do not see environmental migrants as more deserving than economic migrants. These findings have implications for how practitioners address population movements due to climatic changes, and how scholars study people’s attitudes towards environmental migrants. People may choose or be forced to relocate due to climate change. Here the authors show that urban residents in Vietnam and Kenya view climate conditions as a legitimate reason for migration from rural to urban areas, but environmental migrants are not seen as more deserving than economic migrants.

A 7000-year record of floods and ecological feedbacks in Weeks Bay, Alabama, USA

Climate change, sea-level rise, and human activities present major concerns for coastal environments. Paleoenvironmental records allow us to extend the instrumented record and study recent environmental impacts in a long-term context with natural pre-industrial conditions. Here, we investigate grain size, stable carbon (δ13C) and nitrogen (δ15N) isotopes, elemental composition, and diatom abundance in sediments to construct a 7000-year paleoenvironmental history of Weeks Bay, Alabama, a NOAA National Estuarine Research Reserve.Four major floods of the Fish River since 1986 CE are independently identified in the Weeks Bay sediment record, validating the bay setting as an archive of flood events. Thirty-four flood events were identified over the last 5000 years, with two periods of intense flood activity coinciding with the Medieval Climate Anomaly and the Little Ice Age, indicating association of relatively short-term climate events and enhanced storm activity. Further, multiple paleoenvironmental proxies indicate marine conditions during formation of the bay ~6600 calendar years Before Present (cal yr BP) and a brackish transition as the estuary became restricted ~2000 cal yr BP.High total organic carbon/nitrogen values indicate nitrogen limitation in Weeks Bay. Increase in organic content, diatoms, and redox- and nutrient-associated elemental proxies over the last 300 years, with dramatic increase in algal abundance since the 1980s, strongly suggest that human activities (i.e. land clearing, agriculture) increased ecological feedbacks in the bay. Comparing past and present environmental conditions of coastal estuaries advances our understanding of estuarine response to climate change and sea level, floods, and human activities, which is important for environmental management and wetland conservation policy.

Climate regionalization and trends based on daily temperature and precipitation extremes in the south of the Pampas (Argentina)

The south of Pampas (36° 32’-40° 44’ S; 63° 24’-60° 30’ W), as most of Argentina, is a semiarid region. Its economy is based on rain-fed agriculture and livestock. Traditionally, the climate has been studied considering the analyses of monthly and annual climate parameters, but there is evidence that in this type of areas, the short-term climatic events have a substantial impact on the climate. Therefore, this study aimed at developing a climate regionalization from the analysis of daily temperature and precipitation extremes in the south of the Pampas for the period 1970-2017. Subsequently, it focuses on analyzing both trends and breakpoints of these events in the different sub-climates. To do so, we applied a Cluster-based Principal Component Analyses with a Ward hierarchical supervised method to generate a climate regionalization considering 29 daily extreme climatic indices and the elevation. We identify four sub-regions, and we analyzed trends during 1970-2017, and in the two-time series defined by applying breakpoints. Both minimum and maximum temperatures and precipitation had structural changes in the last 15 years, exposing the region to warming and dryness trends. The maximum temperature increases 0.5ºC, while precipitation decreases 30 mm. The short-term climate variability allows us to identify areas climatically more detailed and to conclude that the south of the Pampas is characterized by its high dependency on short-term climatic events.

Nonlinear planetary-synoptic wave interaction under generalized beta effect and its solutions

Abstract The interaction between planetary-scale wave and synoptic-scale wave in atmospheres is important in understanding the physical mechanism of short or long term weather or climate events, such as the blocking phenomena. Kinds of physical factors are disclosed to affect the interaction processes, such as the topography, background current. The effect of beta parameter is investigated in the present paper, it is called the generalized beta effect. By using methods of multiple scales and perturbation expansions, a new nonlinear forced Schrodinger equation is obtained in describing the evolution of planetary-scale envelope Rossby solitary waves, and a modified equation for synoptic-scale waves is derived. By constructing the numerical solution for the nonlinear Schrodinger equation, it reveals that the generalized beta can shift phase and modify the magnitude of planetary-scale envelope solitary waves. An analytical expression for synoptic-scale waves, including the generalized beta effect, is also obtained. It shows that the asymmetry, intensity and persistence of both planetary-scale wave and synoptic-scale wave depend strongly upon the generalized beta. The results provide new theoretical explanations for our understanding of wave-wave interaction.

Late Holocene coastal dynamics, climate pulses and low terraces in the coast of the state of São Paulo, southeast, Brazil

The lower Ribeira de Iguape stream – located in São Paulo, Brazilian southern coast, exhibits complex geomorphologic characteristics that resulted from multiple processes developed during the late Holocene. The present study proposes discussions about the possible relations between short-term climate events from the late Holocene (Climate Pulses) promoting the coastal dynamics and genesis of different levels of low fluvial-marine and marine terraces located in the study area, a subject rarely considered in other studies in humid tropical regions. The procedure of work included grain-size analyses and optically stimulated luminescence (OSL) dating of sediment samples collected from different depositional packages. Four depositional events resulted from transgressive and regressive events geochronologically related with climate pulses from the late Holocene were identified. The events can be summarized as follows: I) Marine Transgression (∼3.5–2.7 ka); II) Marine Regression (2.7–1.8 ka); III) Marine Transgression (1.8–0.65 ka); IV) Marine Regression (0.65–0.10 ka).

The palaeodemographic and environmental dynamics of prehistoric Arctic Norway: An overview of human-climate covariation

This paper presents the first palaeodemographic results of a newly assembled region-wide radiocarbon record of the Arctic regions of northern Norway. The dataset contains a comprehensive collection of radiocarbon dates in the area (N = 1205) and spans the 10,000-year period of hunter-gatherer settlement history from 11500 to 1500 cal BP. Utilizing local, high-resolution palaeoclimate data, the paper performs multi-proxy correlation testing of climate and demographic dynamics, looking for hunter-gatherer responses to climate variability. The paper compares both long-term climate trends and short-term disruptive climate events with the demographic development in the region. The results demonstrate marked demographic fluctuations throughout the period, characterized by a general increase, punctuated by three significant boom and bust-cycles centred on 6000, 3800 and 2200 cal BP, interpreted as instances of climate forcing of human demographic responses. The results strongly suggest the North Cape Current as a primary driver in the local environment and supports the patterns of covariance between coastal climate proxies and the palaeodemographic model. A mechanism of climate forcing mediation through marine trophic webs is proposed as a tentative explanation of the observed demographic fluxes, and a comparison with inter-regional results demonstrate remarkable similarity in demographic trends across mid-Holocene north and west Europe. The results of the north Norwegian radiocarbon record are thus consistent with independent, international efforts, corroborating the existing pan-European results and help further substantiate super-regional climate variability as the primary driver of population dynamics regardless of economic adaptation.

Austrian climate policies and GHG-emissions since 1990: What is the role of climate policy integration?

In 1990 Austria has committed to the Kyoto-protocol and later to the Paris Agreement. Since then, it has developed two climate strategies, has passed its first climate protection act, has adopted a strategy for adaptation to climate change and has implemented many new institutions, programmes and local to provincial climate change mitigation (CCM) measures. Indeed, Austrian GHG-emissions have been decreasing since 2005, giving reasons to suspect policy success. A closer analysis, however, challenges this impression. Here, we put climate policies since 1990 into perspective with other, often short-term drivers of GHG-emissions. Employing a conceptual framework, we evaluate the level of climate policy integration, which has been found key for successful climate policies in literature. This framework also helps us to detect benefits and shortcomings of past and existing CCM policies and so to derive insights relevant for policy-makers. We find that short-term climatic and socio-economic events overruled climate policies in their proximate GHG-emission effects, even when policies were implemented due to EU regulation after 2007. Policy effects are much more difficult to uncover, because they often happen within longer time-frames and are usually accompanied by indirect CCM-effects. In the background of accelerating climate change impacts in combination with associated high uncertainties, strengthening climate policies and integrating reflexive mechanisms that allow adjusting and continuously re-evaluating policy effectiveness, will become ever more important. Eliminating inconsistencies between CCM- and other sectoral policies and drastically reforming accounting schemes to include carbon leakage effects are particularly timely, yet considering political realities, very bold but necessary next step to make climate goals attainable.