A Punctuated Equilibrium Analysis of the Climate Evolution of Cenozoic: Hierarchy of Abrupt Transitions

The Earth's climate has experienced numerous critical transitions during its history, which have often been accompanied by massive and rapid changes in the biosphere. Such transitions are evidenced in various proxy records covering different timescales. The goal is then to identify, date, and rank past critical transitions in terms of importance, thus possibly yielding a more thorough perspective on climatic history. To illustrate such an angle, which inspired the punctuated equilibrium angle on the theory of evolution, we have analyzed 2 key high-resolution datasets: the CENOGRID marine compilation (past 66 Myr), and North Atlantic U1308 record (past 3.3 Myr). By combining recurrence analysis of the individual time series with a multivariate representation of the system based on the theory of the quasi-potential, we identify the key abrupt transitions associated with major regime changes that differentiate various clusters of climate variability. This allows interpreting the time-evolution of the system as a trajectory taking place in a dynamical landscape, whose multiscale features are associated with a hierarchy of tipping points.Comment: 27 pages, 5 figures plus supplementary materia

Repensando a teoria da alteridade e a obra de Josefo

François Hartog é o autor de Espelho de Heródoto - Ensaio sobre a representação do outro, obra a qual nos propomos a analisar quanto à validade de sua metodologia quando se tenta entender a definição de identidade à luz do universo helenístico, em especial no contexto judaico. Tomando Heródoto por modelo, pretendemos trabalhar juntamente a Hartog a construção da identidade do outro como forma de se entender o próprio, utilizando a construção narrativa dos essênios de Flávio Josefo em BJ

Optimizing Models of the North Atlantic Spring Bloom Using Physical, Chemical and Bio-Optical Observations from a Lagrangian Float

The North Atlantic spring bloom is one of the main events that lead to carbon export to the deep ocean and drive oceanic uptake of CO(2) from the atmosphere. Here we use a suite of physical, bio-optical and chemical measurements made during the 2008 spring bloom to optimize and compare three different models of biological carbon export. The observations are from a Lagrangian float that operated south of Iceland from early April to late June, and were calibrated with ship-based measurements. The simplest model is representative of typical NPZD models used for the North Atlantic, while the most complex model explicitly includes diatoms and the formation of fast sinking diatom aggregates and cysts under silicate limitation. We carried out a variational optimization and error analysis for the biological parameters of all three models, and compared their ability to replicate the observations. The observations were sufficient to constrain most phytoplankton-related model parameters to accuracies of better than 15 %. However, the lack of zooplankton observations leads to large uncertainties in model parameters for grazing. The simulated vertical carbon flux at 100 m depth is similar between models and agrees well with available observations, but at 600 m the simulated flux is larger by a factor of 2.5 to 4.5 for the model with diatom aggregation. While none of the models can be formally rejected based on their misfit with the available observations, the model that includes export by diatom aggregation has a statistically significant better fit to the observations and more accurately represents the mechanisms and timing of carbon export based on observations not included in the optimization. Thus models that accurately simulate the upper 100 m do not necessarily accurately simulate export to deeper depths

A reliable benchmark of the last 640,000 years millennial climate variability

How often have past climates undergone abrupt transitions? While our understanding of millennial variability during the past 130,000 years is well established, with precise dates available, such information on previous climate cycles is limited. To address this question, we identified 196 abrupt transitions in the δ18O record of the well-dated Chinese composite speleothem for the last 640,000 years. These results correspond to abrupt changes in the strength of the East Asian Monsoon, which align with the Greenland stadials and interstadials observed in the North Atlantic region during the last 130,000 years before present. These precise dates of past abrupt climate changes constitute a reliable and necessary benchmark for Earth System models used to study future climate scenarios

A punctuated equilibrium analysis of the climate evolution of cenozoic exhibits a hierarchy of abrupt transitions

The Earth's climate has experienced numerous critical transitions during its history, which have often been accompanied by massive and rapid changes in the biosphere. Such transitions are evidenced in various proxy records covering different timescales. The goal is then to identify, date, characterize, and rank past critical transitions in terms of importance, thus possibly yielding a more thorough perspective on climatic history. To illustrate such an approach, which is inspired by the punctuated equilibrium perspective on the theory of evolution, we have analyzed 2 key high-resolution datasets: the CENOGRID marine compilation (past 66 Myr), and North Atlantic U1308 record (past 3.3 Myr). By combining recurrence analysis of the individual time series with a multivariate representation of the system based on the theory of the quasi-potential, we identify the key abrupt transitions associated with major regime changes that separate various clusters of climate variability. This allows interpreting the time-evolution of the system as a trajectory taking place in a dynamical landscape, whose multiscale features describe a hierarchy of metastable states and associated tipping points

Detection of abrupt changes in East Asian monsoon from Chinese loess and speleothem records

Abrupt climate changes, especially at millennial timescales, have become a key topic in paleoclimatology because of their link with the tipping point theory and their extensive impacts on future climate scenarios. Although best documented in ice-cores and marine sediments, they are also recorded in different archives on the land, among which Chinese loess and speleothem records are of particular interest. These records effectively document orbital-to-millennial monsoon variability during the Pleistocene, but the dominant periodicity revealed by proxy records from these two types of archives is different. Nevertheless, millennial-scale oscillations recorded in Chinese loess and speleothem records seem highly similar over the last several glacial cycles. Such millennial fluctuations can be of varying amplitudes, and either more or less abrupt depending on the type of record. The observed abruptness usually depends on the sedimentation rates and sampling resolution in the loess and speleothem records. However, it can also be refined by comparisons with multiple physicochemical and isotopic proxies. Here, we apply a robust statistical method to detect abrupt changes in loess grain size and speleothem δ18O records. As a first step, we compared two reference records (i.e. the NGRIP ice-core and the Hulu speleothem δ18O records) of abrupt climate change to verify the robustness of our method in detecting the well-recognized abrupt events during the last glaciation. This result allows us, in a second step, to compare two high-resolution loess grain-size stacks (i.e. the CHILOMOS, and the LGS640 datasets) with the Chinese speleothem composite record built from Hulu and Sanbao records. Although visually observed rapid grain-size variations were previously interpreted as representing millennial-scale variations, our statistical analysis confirms that whether these abrupt climate changes can be robustly identified is highly dependent on the time resolution of the studied records. In a third step, we detected abrupt transitions in the MGSQ grain size stack, covering the last 3.6 Myrs. Our results also show that both winter and summer monsoons co-varied at glacial-interglacial to millennial timescales, reflecting a three-stage evolution of increasing intensity: (1) from 3.6 Ma to 2.6 Ma, (2) from 2.6 Ma to 1.2 Ma, and (3) from 1.2 Ma to present. Our results finally show that the identified abrupt climate events can be employed for synchronizing climate records on a global scale

The PaleoJump database for abrupt transitions in past climates

Tipping points (TPs) in Earth’s climate system have been the subject of increasing interest and concern in recent years, given the risk that anthropogenic forcing could cause abrupt, potentially irreversible, climate transitions. Paleoclimate records are essential for identifying past TPs and for gaining a thorough understanding of the underlying nonlinearities and bifurcation mechanisms. However, the quality, resolution, and reliability of these records can vary, making it important to carefully select the ones that provide the most accurate representation of past climates. Moreover, as paleoclimate time series vary in their origin, time spans, and periodicities, an objective, automated methodology is crucial for identifying and comparing TPs. To address these challenges, we introduce the opensource PaleoJump database, which contains a collection of carefully selected, high-resolution records originating in ice cores, marine sediments, speleothems, terrestrial records, and lake sediments. These records describe climate variability on centennial, millennial and longer time scales and cover all the continents and ocean basins. We provide an overview of their spatial distribution and discuss the gaps in coverage. Our statistical methodology includes an augmented Kolmogorov–Smirnov test and Recurrence Quantification Analysis; it is applied here, for illustration purposes, to selected records in which abrupt transitions are automatically detected and the presence of potential tipping elements is investigated. These transitions are shown in the PaleoJump database along with other essential information about the records, including location, temporal scale and resolution, as well as temporal plots. This open-source database represents, therefore, a valuable resource for researchers investigating TPs in past climates

Geochemical response of the mid-depth Northeast Atlantic Ocean to freshwater input during Heinrich events 1 to 4

PublishedArticleHeinrich events are intervals of rapid iceberg-sourced freshwater release to the high latitude North Atlantic Ocean that punctuate late Pleistocene glacials. Delivery of fresh water to the main North Atlantic sites of deep water formation during Heinrich events may result in major disruption to the Atlantic Meridional Overturning Circulation (AMOC), however, the simple concept of an AMOC shutdown in response to each freshwater input has recently been shown to be overly simplistic. Here we present a new multi-proxy dataset spanning the last 41,000 years that resolves four Heinrich events at a classic mid-depth North Atlantic drill site, employing four independent geochemical tracers of water mass properties: boron/calcium, carbon and oxygen isotopes in foraminiferal calcite and neodymium isotopes in multiple substrates. We also report rare earth element distributions to investigate the fidelity by which neodymium isotopes record changes in water mass distribution in the northeast North Atlantic. Our data reveal distinct geochemical signatures for each Heinrich event, suggesting that the sites of fresh water delivery and/or rates of input played at least as important a role as the stage of the glacial cycle in which the fresh water was released. At no time during the last 41 kyr was the mid-depth northeast North Atlantic dominantly ventilated by southern-sourced water. Instead, we document persistent ventilation by Glacial North Atlantic Intermediate Water (GNAIW), albeit with variable properties signifying changes in supply from multiple contributing northern sources.This research used samples provided by the Integrated Ocean Drilling (Discovery) Program IODP, which is sponsored by the US National Science Foundation and participating countries under management of Joint Oceanographic Institutions, Inc. We thank Walter Hale and Alex Wülbers for help with sampling, Kirsty Crocket for providing additional samples and Matt Cooper, Andy Milton, Mike Bolshaw and Dave Spanner for analytical support. Heiko Pälike, David Thornalley and Rachel Mills are thanked for productive discussions and comments on earlier versions of this work. We also thank three anonymous reviewers for their constructive feedback, which greatly improved the manuscript. Funding for this project was provided by NERC studentships to A.J.C. (grant NE/D005728/2) and T.B.C. (NE/I528626/1), with additional funding support from a Royal Society Wolfson Research Merit Award and NERC grants NE/F00141X/1 and NE/I006168/1 to P.A.W. and NE/D00876X/2 to G.L.F

The impact of FinTech development on traditional banking institutions in Poland

Szybko postępująca cyfryzacja i unowocześnianie technologii informacyjnych dają impuls do korzystania z innowacyjnych rozwiązań proponowanych przez szeroko rozumiany sektor finansów. W prezentowanej pracy przedstawiono rozwój systemu bankowego w Polsce, perspektywę zjawiska FinTech (technologie finansowe) ze zwróceniem uwagi na funkcjonujące oddziały bankowe a także innowacyjne rozwiązania finansowe. Celem artykułu jest analiza wpływu rozwoju FinTech na stacjonarne oddziały instytucji bankowych w Polsce. Autorzy zwracają uwagę na zmiany w zachowaniach właścicieli kont bankowych, na przykład sposób wypłaty gotówki. Głównym źródłem informacji wykorzystanych w artykule są dane uzyskane w wyniku przeprowadzenia ankiety. Analiza wyników badań pokazuje, że tradycyjne oddziały bankowe stają się zbędne oraz nieopłacalne i powoli z roku na rok ich liczba będzie maleć. Autorzy zwracają także uwagę na niesamowity fenomen BLIKA, który coraz częściej zastępuje inne metody płatności proponowane przez banki.The rapidly advancing digitisation and modernisation of information technologies are an impulse to use innovative solutions proposed by the broadly understood financial sector. The presented work presents the development of the banking system in Poland, the perspective of the FinTech phenomenon, with focus on operating bank branches in Poland, as well as innovative solutions. The aim of the article is to analyse the impact of FinTech development on traditional branches of banking institutions in Poland. The authors look at today’s behavior of bank account holders with regard to everyday activities, such as withdrawing cash. At the same time they make suggestions as to the reason for the presented results, in order to clearly formulate the final conclusions. The authors also discuss areas analogous to the main topic, such as cashless payment methods, with a closer analysis of their real impact on the banking structure. The main source of information for this article are results obtained from the authors’ own research. The considerations lead to the conclusion that in today’s banking environment bank branches are somewhat unnecessary and unprofitable, and will slowly decrease in number year by year. The results of the study highlight the amazing BLIK phenomenon, which is increasingly replacing payment methods offered by banks