Reconstructing Neogene surface uplift of the Alps: Integrating stable isotope paleoaltimetry and paleoclimate modelling

Paleoaltimetry - the reconstruction of the elevation of mountain ranges in the geological past - is key to understanding the geodynamic drivers of surface uplift. Simultaneously, surface uplift of Earth’s major mountain ranges redirected atmospheric flow and impacted climate globally. At a smaller scale, mountain building affects regional climate and biodiversity. Stable isotope paleoaltimetry is a powerful tool to quantify the past elevation of mountain ranges. It is based on the inverse relationship between the stable isotopic composition of meteoric waters and elevation, which is represented by the so-called isotopic lapse rate. However, variations in climatic parameters modify isotopic lapse rates and impact moisture transport over the continents and consequently affect paleoelevation reconstructions. Here, we show the results of a combined stable isotope paleoaltimetry and paleoclimate modeling approach in the European Alps. This approach allows for an improved and more realistic estimation of isotopic lapse rates, large-scale isotope-in-precipitation patterns over Europe and hence Alpine paleoaltimetry calculations. The European Alps are an ideal target for a combined paleoaltimetry - climate modeling approach, given that they are (a) one of the most-studied mountain ranges for which many geoscientific data are available, and (b) sufficiently small and oriented near-parallel to dominant atmospheric circulation patterns. The latter implies that no major global climatic changes are expected in response to Alpine surface uplift, as opposed to e.g. the Andes or the Tibet-Himalaya mountain ranges. Results from 4D-MB SPP phase 1 and 2 show that: (1) Changing the surface elevation of even a small orogen can complicate stable isotope paleoaltimetry by mixing the elevation and climate signal in a more complex way than commonly assumed. Climate models can help separate these signals and constrain surface uplift histories. (2) The Central Alps were already high during the Early and Middle Miocene, whereas the Eastern Alps were still at significantly lower elevations, thereby confirming that surface uplift propagated from west to east, as would be expected from oblique continent-continent collision. Together, the results highlight the importance and viability of this combined, interdisciplinary approach. Based on the results from 4D-MB SPP phase 1 and 2, we propose that future efforts to reconstruct surface uplift of mountain ranges follow this state-of-the-art approach, while keeping local limitations to proxy material availability and access to facilities in mind

Spannung bis zum Abpfiff: Die Prognose des Fußballweltmeisters ist schwieriger als bei der letzten WM

Anlässlich der Fußballweltmeisterschaft 2006 wurde erstmals der Marktwert der Mannschaften ('Transferwert') als eine einfache und transparente Basis für die Prognose des Ausgangs eines großen Fußballturniers vorgeschlagen. Und tatsächlich wurden die Teams mit den höchsten Marktwerten 2006 und 2010 ebenso FIFA-Weltmeister (Italien und Spanien), wie das teuerste Team der Jahre 2008 und 2012 Europameister wurde (Spanien). Der Sieger der kommenden Fußballweltmeisterschaft in Brasilien lässt sich auf dieselbe Weise vorhersagen, allerdings fällt die Prognose dieses Mal deutlich schwerer. Denn die Mannschaften des erweiterten Favoritenkreises liegen - gemessen am Marktwert des Mannschaftskaders - enger beieinander als beim letzten Turnier, als die spanische Auswahlmannschaft deutlich die teuerste war. Es könnten daher - wie 2006, als es an der Spitze auch eng war - andere Faktoren den Fußballweltmeister ausmachen: Fitness, Tagesform - und der Zufall.At the FIFA World Cup 2006, the method of using the market value of the teams ('transfer value') was first proposed as a simple and transparent basis for forecasting the outcome of a major football tournament. Indeed, the countries with players of the highest market value were world champions in 2006 and 2010 (Italy and Spain, respectively), just as the most expensive team won the European Championships in 2008 and 2012 (Spain). The winner of the upcoming World Cup in Brazil can be forecast in the same way, but it is considerably more difficult to predict the result this time around. This is because the top teams are much more evenly matched - in terms of the market value of the whole squad - than in the previous tournaments when the Spanish team was clearly the most expensive one. Consequently, other factors come into play, such as level of fitness, daily form, and chance, as they did in 2006 when the top teams were also very evenly matched

The effects of late Cenozoic climate change on the global distribution of frost cracking

Frost cracking is a dominant mechanical weathering phenomenon facilitating the breakdown of bedrock in periglacial regions. Despite recent advances in understanding frost cracking processes, few studies have addressed how global climate change over the late Cenozoic may have impacted spatial variations in frost cracking intensity. In this study, we estimate global changes in frost cracking intensity (FCI) by segregation ice growth. Existing process-based models of FCI are applied in combination with soil thickness data from the Harmonized World Soil Database. Temporal and spatial variations in FCI are predicted using surface temperature changes obtained from ECHAM5 general circulation model simulations conducted for four different paleoclimate time slices. Time slices considered include pre-industrial (∼ 1850 CE, PI), mid-Holocene (∼ 6 ka, MH), Last Glacial Maximum (∼ 21 ka, LGM), and Pliocene (∼ 3 Ma, PLIO) times. Results indicate for all paleoclimate time slices that frost cracking was most prevalent (relative to PI times) in the middle- to high-latitude regions, as well as high-elevation lower-latitude areas such the Himalayas, Tibet, the European Alps, the Japanese Alps, the US Rocky Mountains, and the Andes Mountains. The smallest deviations in frost cracking (relative to PI conditions) were observed in the MH simulation, which yielded slightly higher FCI values in most of the areas. In contrast, larger deviations were observed in the simulations of the colder climate (LGM) and warmer climate (PLIO). Our results indicate that the impact of climate change on frost cracking was most severe during the PI–LGM period due to higher differences in temperatures and glaciation at higher latitudes. The PLIO results indicate low FCI in the Andes and higher values of FCI in Greenland and Canada due to the diminished extent of glaciation in the warmer PLIO climate.</p

Empirical glacier mass-balance models for South America

We investigate relationships between synoptic-scale atmospheric variability and the mass-balance of 13 Andean glaciers (located 16–55° S) using Pearson correlation coefficients (PCCs) and multiple regressions. We then train empirical glacier mass-balance models (EGMs) in a cross-validated multiple regression procedure for each glacier. We find four distinct glaciological zones with regard to their climatic controls: (1) The mass-balance of the Outer Tropics glaciers is linked to temperature and the El Niño-Southern Oscillation (PCC ⩽ 0.6), (2) glaciers of the Desert Andes are mainly controlled by zonal wind intensity (PCC ⩽ 0.9) and the Antarctic Oscillation (PCC ⩽0.6), (3) the mass-balance of the Central Andes glaciers is primarily correlated with precipitation anomalies (PCC ⩽ 0.8), and (4) the glacier of the Fuegian Andes is controlled by winter precipitation (PCC ≈ 0.7) and summer temperature (PCC ≈ −0.9). Mass-balance data in the Lakes District and Patagonian Andes zones, where most glaciers are located, are too sparse for a robust detection of synoptic-scale climatic controls. The EGMs yield R2 values of ~ 0.45 on average and ⩽ 0.74 for the glaciers of the Desert Andes. The EGMs presented here do not consider glacier dynamics or geometry and are therefore only suitable for short-term predictions

pyESDv1.0.1: an open-source Python framework for empirical-statistical downscaling of climate information

The nature and severity of climate change impacts vary significantly from region to region. Consequently, high-resolution climate information is needed for meaningful impact assessments and the design of mitigation strategies. This demand has led to an increase in the application of empirical-statistical downscaling (ESD) models to general circulation model (GCM) simulations of future climate. In contrast to dynamical downscaling, the perfect prognosis ESD (PP-ESD) approach has several benefits, including low computation costs, the prevention of the propagation of GCM-specific errors, and high compatibility with different GCMs. Despite their advantages, the use of ESD models and the resulting data products is hampered by (1) the lack of accessible and user-friendly downscaling software packages that implement the entire downscaling cycle, (2) difficulties reproducing existing data products and assessing their credibility, and (3) difficulties reconciling different ESD-based predictions for the same region. We address these issues with a new open-source Python PP-ESD modeling framework called pyESD. pyESD implements the entire downscaling cycle, i.e., routines for data preparation, predictor selection and construction, model selection and training, evaluation, utility tools for relevant statistical tests, visualization, and more. The package includes a collection of well-established machine learning algorithms and allows the user to choose a variety of estimators, cross-validation schemes, objective function measures, and hyperparameter optimization in relatively few lines of code. The package is well-documented, highly modular, and flexible. It allows quick and reproducible downscaling of any climate information, such as precipitation, temperature, wind speed, or even short-term glacier length and mass changes. We demonstrate the use and effectiveness of the new PP-ESD framework by generating weather-station-based downscaling products for precipitation and temperature in complex mountainous terrain in southwestern Germany. The application example covers all important steps of the downscaling cycle and different levels of experimental complexity. All scripts and datasets used in the case study are publicly available to (1) ensure the reproducibility and replicability of the modeled results and (2) simplify learning to use the software package

The Alps Paleoelevation and Paleoclimate Experiment (APE): Neogene Paleoelevation and Paleoclimate of the Central Alps

Stable isotope paleoaltimetry takes advantage of the relationship between orogen elevation and the stable isotope ratios in meteoric water, which are ultimately recorded in geological archives like foreland basins or orogen-internal shear zones. The δ-δ approach relies on contrasting time-equivalent δ18O and δD records from high- and low-elevation sites to constrain the height of the orogen at the time these geologic archives were formed. However, at the same time, different boundary conditions such as changing paleogeography, atmospheric CO2 concentrations or sea surface temperatures result in complex paleoclimate model outputs, which predict significant changes in the isotopic composition of meteoric water. These changes may be recorded in geological archives and thus complicate the reconstruction of past elevations. The 4DMB Phase 1 project APE aimed at generating a first quantitative estimate for the paleoclimatic signal in Alpine stable isotope records, so that these records may be corrected for and ultimately yield more accurate paleoelevation estimates. We addressed this challenge by integrating isotope-tracking climate model (ECHAM5-wiso) simulations with stable isotope and clumped isotope data from the foreland basin and high-elevation regions of the central Alps. ECHAM5-wiso simulations have been conducted with 1) boundary conditions based on paleogeographic reconstructions of the Last Glacial Maximum (LGM) and the mid-Pliocene (PLIO), and 2) different topographic scenarios for the Alps. The simulations show that modifying environmental conditions can produce similar magnitudes of δ18O change as changes in alpine topography. For example, the climatically induced δ18O changes in the PLIO and LGM experiments correspond to the magnitude of changes created by setting the entire orogen to 50% and 150% of its modern height, respectively (Botsyun et al., 2020). Our modelling results stress the need for the paleoaltimetry community to correct isotopic signals in geologic archives for climate-induced changes in isotope ratios. Pedogenic carbonate proxy data from alluvial megafans of the Swiss Molasse Basin revealed that 1) low-elevation, distal δ18O values are higher than previously assumed and thus, more adequately reflect low-elevation δ18O values required for paleoelevation estimates; 2) Mid-Miocene megafans had considerable topography and an internal elevation gradient; 3) clumped isotope-derived carbonate formation temperatures yield low-elevation paleoclimate estimates and help to embed δ18O data into global climate models. Under consideration of previous work and our modelling results, we conclude that the Central Alps, more specifically the region surrounding the Simplon Fault Zone, attained surface elevations of >4000 m no later than the mid-Miocene (Krsnik et al., 2021). In summary, our approach represents an important methodological advance that allows the disentangling of climatic and surface uplift signals in the geologic stable isotope record. Furthermore, new insights into the Alps elevation history can help to constrain the timing of slab inversion and/or break-off in the Western/Central Alps

Predictable Winners. Market Value, Inequality, Diversity, and Routine as Predictors of Success in European Soccer Leagues

Vermarktlichung und Globalisierung haben den Profifußball und die Zusammensetzung von Mannschaften fundamental verändert. Vor dem Hintergrund der veränderten Rahmenbedingungen untersucht der Beitrag, in welchem Maße (a) der Marktwert einer Mannschaft, (b) ihre interne Ungleichheit, (c) die kulturelle Diversität eines Teams sowie (d) der Grad der Fluktuation im Team über den sportlichen Erfolg in nationalen Meisterschaften entscheiden. Die empirische Analyse bezieht sich für die Spielsaison 2012/13 auf die zwölf leistungsstärksten nationalen Fußball-Ligen Europas. Die Ergebnisse zeigen, dass der Ausgang von nationalen Fußballmeisterschaften auf der Basis unserer Hypothesen sehr gut vorausgesagt werden kann; fast alle unsere Hypothesen werden bestätigt. Dem Marktwert der Mannschaften kommt dabei die mit deutlichem Abstand wichtigste Rolle in der Prognose ihres Erfolgs zu.Marketization and globalization have changed professional soccer and the composition of soccer teams fundamentally. Against the background of these shifting conditions this paper investigates the extent to which the success of soccer teams in their national leagues is determined by (a) the monetary value of the team expressed in its market value, (b) inequality within the team, (c) the cultural diversity of the team, and (d) the degree of turnover among team members. The empirical analyses refer to the soccer season 2012/13 and include the twelve most important European soccer leagues. The findings demonstrate that success in a national soccer championship is highly predictable; nearly all of our hypotheses are confirmed. The market value of the team is, in today's world, by far the most important single predictor of athletic success in professional soccer

The Alps Paleoelevation and Paleoclimate Experiment: Reconstructing Eastward Propagation of Surface Uplift in the ALps (REAL)

Geological observations, geodynamic models, and seismic studies suggest Neogene eastward propagating surface uplift of the European Alps. Whereas 4DMB Phase I project APE focused on reconstructing surface uplift of the Central Alps, 4DMB Phase II project REAL aims at testing the predicted west-to-east surface uplift of the Alps by combining stable isotope paleoaltimetry and paleoclimate modeling. Stable isotope paleoaltimetry is based on the inverse relationship between elevation and the stable isotopic composition of meteoric water and provides a tool to reconstruct the elevation of mountain belts in the geological past. First, REAL explores applications of the δ-δ method (see Poster Phase I APE), which requires that various recorders of past rainfall are available in the rock record: soil carbonates from low-elevation (foreland) basins and hydrous minerals from high-elevation fault gouges/shear zones. Paleoelevation estimates are obtained by contrasting time-equivalent low- and high-elevation proxy data sets, provided that the isotopic composition of the fluids during mineral formation is estimated accurately. Whereas formation temperatures of fault gouge minerals (such as illite and syntectonic micas) can be readily estimated, we apply clumped isotope paleothermometry to provide robust estimates of meteoric water δ18O from the low-elevation foreland basin carbonate record. Second, meteoric water δ18O values are not only sensitive to local elevation, but also to the complex climatic changes resulting from different paleoenvironmental boundary conditions and regional topographic configuration. To isolate the contribution of each of these components δ-δ stable isotope paleoaltimetry is applied in combination with ECHAM5-wiso paleoclimate simulations for a number of topographic scenarios of diachronous surface uplift. This unique combination allows for the removal of climate change effects on the stable isotope data, and therefore improves the accuracy of paleoelevation reconstructions. Results from our ongoing Phase II project (spring 2021 - spring 2024): 1. Reveal that diachronous surface uplift would produce patterns of climate, δ18O in precipitation values, and isotopic lapse rates that are distinctly different from those of today and those produced by bulk surface uplift scenarios. Importantly, this signal would be detectable in stable isotope paleoaltimetry results (Boateng et al., in revision). 2. Present a Miocene (23–13 Ma) continental paleotemperature record from the northern Mediterranean region (Digne-Valensole basin, SE France), which indicates near-constant temperatures from 23.0-18.8 Ma, followed by a highly variable and warm climate during the Middle Miocene and rapid cooling after 14 Ma (Ballian et al., 2023). 3. Together with new and existing paleotemperature records, preliminary results of the δ-δ method show for the first time that (a) the Central Alps were already high during the Early Miocene and (b) the Eastern Alps were appreciably lower than the Central Alps during the Middle Miocene (Ballian et al., 2022)

Synergistic effects of diachronous surface uplift and global climate change on the isotopic composition of meteoric waters: implications on paleoelevation estimates across the European Alps

Stable isotope paleoaltimetry is widely used to infer past elevations of orogens due to the robust systematic inverse relationships between elevation and oxygen (δ18O) and hydrogen (δD) isotopic composition of meteoric waters recorded in geologic archives, such as paleosol carbonates or hydrous silicates. This δ18O-elevation relationship (or isotopic lapse rate) is commonly attributed to the preferential rainout of heavy water isotopologues from air masses ascending over topography. However, numerous non-linear climatic processes, such as surface recycling, vapor mixing, variability in moisture source, and precipitation dynamics, can also influence the isotopic lapse rate and thus complicate stable isotope paleoaltimetry estimates. This highlights the need for a better quantitative understanding of topographic and regional climatic effects on the isotopic composition of ancient waters. Through topographic sensitivity experiments, Boateng et al. (2023) suggested plausible changes in isotopic lapse rates across the Alps in response to different diachronous surface uplift scenarios and validated that the expected isotopic signal difference due to elevation changes is significant enough to be reflected in geologic archives. Recent paleoelevation reconstructions across the Alps estimate the mean elevation of >4000 m in the Central Alps during the Middle Miocene (Krsnik et al., 2021). These high elevation estimates have been attributed to the complicated transition from pre- to mid-Miocene Central Alps with a diverse landscape and a complex topography, mainly driven by the rapid exhumation of deep-seated core complexes, followed by a rearrangement of the drainage system. However, the paleoelevation estimate is based on the assumptions that the isotopic lapse rate (1) is similar to the modern lapse rate (~2.0 ‰/km), which is lower than the global average, (2) did not change during the deposition of the paleoaltimetry proxies compared to the present day, and (3) remained constant across the entire Alps. Here, we use a high-resolution isotope-tracking ECHAM5-wiso General Circulation Model to simulate the Middle Miocene climate and δ18Op responses to different surface uplift scenarios of the Alps. More specifically, we performed topographic sensitivity experiments by varying the height of the Western/Central Alps and Eastern Alps under two atmospheric CO2 concentration scenarios for Middle Miocene paleoenvironmental conditions. The simulated δ18Op values are consistent with the proxy reconstructions across the low- and high-elevation sites in the Alps. The topographic scenarios indicated δ18Op values differences of up to -10 ‰ between the low- and high-elevation sites, primarily due to changes in orographic precipitation and local near-surface temperature. Even though the differences across the low-elevation sites showed minor changes compared to the present-day climate, the high-elevation sites indicated significant changes mainly due to differences in moisture transport and moisture redistribution. These changes resulted in different isotopic lapse rates across the different transects around the Alps, contradicting the assumption of a regionally similar isotopic lapse rate. Using the simulated Middle Miocene isotopic lapse rates with the reconstructed Δδ18Op signal between the low-elevation Northern Alpine Foreland Basin and high-elevation Simplon fault gouge reveals an overestimation of paleoelevation estimates by 2 km when compared to the constant isotopic lapse rate of -2.0 ‰/km across the Alps. These uncertainty estimates are an improvement of the previous paleoelevation reconstruction across the Alps and support the integration of paleoaltimetry and paleoclimate modelling to reconstruct past surface elevations accurately

Cenozoic proxy constraints on Earth system sensitivity to greenhouse gases

The long-term extent of the Earth system response to anthropogenic interference remains uncertain. However, the geologic record offers insights into this problem as Earth has previously cycled between warm and cold intervals during the Phanerozoic. We present an updated compilation of surface temperature proxies for several key time intervals to reconstruct global temperature changes during the Cenozoic. Our data synthesis indicates that Earth’s surface slowly cooled by ca. 9°C during the early Paleogene to late Neogene and that continent-scale ice sheets developed after global temperature dropped to less than 10°C above preindustrial conditions. Slow cooling contrasts with the steep decrease in combined radiative forcing from past CO2 concentrations, solar luminosity, and ocean area, which was close to preindustrial levels even as Earth remained in a much warmer state. From this, we infer that the Earth system was less sensitive to greenhouse gas forcing for most of the Cenozoic and that sensitivity must have increased by at least a factor of 2 during the Plio-Pleistocene. Our results imply that slow feedbacks will raise global surface temperatures by more than 3°C in the coming millennia, even if anthropogenic forcing is stabilized at the present-day value (2 W/m2), and that their impact will diminish with further warming