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Combined impacts of future climate-driven vegetation changes and socioeconomic pressures on protected areas in Africa (2022)
Martens, Carola ; Scheiter, Simon ; Midgley, Guy F. ; Hickler, Thomas
Africa's protected areas (PAs) are the last stronghold of the continent's unique biodiversity, but they appear increasingly threatened by climate change, substantial human population growth, and land-use change. Conservation planning is challenged by uncertainty about how strongly and where these drivers will interact over the next few decades. We investigated the combined future impacts of climate-driven vegetation changes inside African PAs and human population densities and land use in their surroundings for 2 scenarios until the end of the 21st century. We used the following 2 combinations of the shared socioeconomic pathways (SSPs) and representative greenhouse gas concentration pathways (RCPs): the “middle-of-the-road” scenario SSP2–RCP4.5 and the resource-intensive “fossil-fueled development” scenario SSP5–RCP8.5. Climate change impacts on tree cover and biome type (i.e., desert, grassland, savanna, and forest) were simulated with the adaptive dynamic global vegetation model (aDGVM). Under both scenarios, most PAs were adversely affected by at least 1 of the drivers, but the co-occurrence of drivers was largely region and scenario specific. The aDGVM projections suggest considerable climate-driven tree cover increases in PAs in today's grasslands and savannas. For PAs in West Africa, the analyses revealed climate-driven vegetation changes combined with hotspots of high future population and land-use pressure. Except for many PAs in North Africa, future decreases in population and land-use pressures were rare. At the continental scale, SSP5–RCP8.5 led to higher climate-driven changes in tree cover and higher land-use pressure, whereas SSP2–RCP4.5 was characterized by higher future population pressure. Both SSP–RCP scenarios implied increasing challenges for conserving Africa's biodiversity in PAs. Our findings underline the importance of developing and implementing region-specific conservation responses. Strong mitigation of future climate change and equitable development scenarios would reduce ecosystem impacts and sustain the effectiveness of conservation in Africa.
Synergistic HNO3–H2SO4–NH3 upper tropospheric particle formation (2022)
Wang, Mingyi ; Xiao, Mao ; Bertozzi, Barbara ; Marie, Guillaume ; Rörup, Birte ; Schulze, Benjamin ; Bardakov, Roman ; He, Xu-Cheng ; Shen, Jiali ; Scholz, Wiebke ; Marten, Ruby ; Dada, Lubna ; Baalbaki, Rima ; Lopez, Brandon ; Lamkaddam, Houssni ; Manninen, Hanna E. ; Amorim, Antonio ; Ataei, Farnoush ; Bogert, Pia ; Brasseur, Zoé ; Caudillo, Lucía ; De Menezes, Louis-Philippe ; Duplissy, Jonathan ; Ekman, Annica M. L. ; Finkenzeller, Henning ; Gonzalez Carracedo, Loïc ; Granzin, Manuel ; Guida, Roberto ; Heinritzi, Martin ; Hofbauer, Victoria ; Höhler, Kristina ; Korhonen, Kimmo ; Krechmer, Jordan E. ; Kürten, Andreas ; Lehtipalo, Katrianne ; Mahfouz, Naser G. A. ; Makhmutov, Vladimir ; Massabò, Dario ; Mathot, Serge ; Mauldin, Roy L. ; Mentler, Bernhard ; Müller, Tatjana ; Onnela, Antti ; Petäjä, Tuukka ; Philippov, Maxim ; Piedehierro, Ana A. ; Pozzer, Andrea ; Ranjithkumar, Ananth ; Schervish, Meredith ; Schobesberger, Siegfried ; Simon, Mario ; Stozhkov, Yuri ; Tomé, António ; Umo, Nsikanabasi Silas ; Vogel, Franziska ; Wagner, Robert ; Wang, Dongyu S. ; Weber, Stefan K. ; Welti, André ; Wu, Yusheng ; Zauner-Wieczorek, Marcel ; Sipilä, Mikko ; Winkler, Paul M. ; Hansel, Armin ; Baltensperger, Urs ; Kulmala, Markku ; Flagan, Richard C. ; Curtius, Joachim ; Riipinen, Ilona ; Gordon, Hamish ; Lelieveld, Jos ; El Haddad, Imad ; Volkamer, Rainer ; Worsnop, Douglas R. ; Christoudias, Theodoros ; Kirkby, Jasper ; Möhler, Ottmar ; Donahue, Neil M.
New particle formation in the upper free troposphere is a major global source of cloud condensation nuclei (CCN)1,2,3,4. However, the precursor vapours that drive the process are not well understood. With experiments performed under upper tropospheric conditions in the CERN CLOUD chamber, we show that nitric acid, sulfuric acid and ammonia form particles synergistically, at rates that are orders of magnitude faster than those from any two of the three components. The importance of this mechanism depends on the availability of ammonia, which was previously thought to be efficiently scavenged by cloud droplets during convection. However, surprisingly high concentrations of ammonia and ammonium nitrate have recently been observed in the upper troposphere over the Asian monsoon region5,6. Once particles have formed, co-condensation of ammonia and abundant nitric acid alone is sufficient to drive rapid growth to CCN sizes with only trace sulfate. Moreover, our measurements show that these CCN are also highly efficient ice nucleating particles—comparable to desert dust. Our model simulations confirm that ammonia is efficiently convected aloft during the Asian monsoon, driving rapid, multi-acid HNO3–H2SO4–NH3 nucleation in the upper troposphere and producing ice nucleating particles that spread across the mid-latitude Northern Hemisphere.
New CA-ID-TIMS U–Pb zircon ages for the Altenberg–Teplice Volcanic Complex (ATVC) document discrete and coeval pulses of Variscan magmatic activity in the Eastern Erzgebirge (Eastern Variscan Belt) (2022)
Tichomirowa, Marion ; Käßner, Alexandra ; Repstock, Alexander ; Weber, Sebastian ; Gerdes, Axel ; Whitehouse, Martin J.
The Altenberg–Teplice Volcanic Complex (ATVC) is a large ~ NNW–SSE trending volcano-plutonic system in the southern part of the Eastern Erzgebirge (northern Bohemian Massif, south-eastern Germany and northern Czech Republic). This study presents high precision U–Pb CA-ID-TIMS zircon ages for the pre-caldera volcano-sedimentary Schönfeld–Altenberg Complex and various rocks of the caldera stage: the Teplice rhyolite, the microgranite ring dyke, and the Sayda-Berggießhübel dyke swarm. These data revealed a prolonged time gap of ca. 7–8 Myr between the pre-caldera stage (Schönfeld–Altenberg Complex) and the climactic caldera stage. The volcanic rocks of the Schönfeld–Altenberg Complex represent the earliest volcanic activity in the Erzgebirge and central Europe at ca. 322 Ma. The subsequent Teplice rhyolite was formed during a relatively short time interval of only 1–2 Myr (314–313 Ma). During the same time interval (314–313 Ma), the microgranite ring dyke intruded at the rim of the caldera structure. In addition, one dyke of the Sayda-Berggiesshübel dyke swarm was dated at ca. 314 Ma, while another yielded a younger age (ca. 311 Ma). These data confirm the close genetic and temporal relationship of the Teplice rhyolite, the microgranite ring dyke, and (at least part of) the Sayda-Berggießhübel dyke swarm. Remarkably, the caldera formation in the south of the Eastern Erzgebirge (caldera stage of ATVC: 314–313 Ma) and that in the north (Tharandt Forest caldera: 314–312 Ma) occurred during the same time. These data document a large ~ 60 km NNW–SSE trending magmatic system in the whole Eastern Erzgebirge. For the first time, Hf-O-isotope zircon data was acquired on the ring dyke from the ATVC rocks to better characterize its possible sources. The homogeneous Hf-O-isotope zircon data from the microgranite ring dyke require preceding homogenization of basement rocks. Some small-scale melts that were produced during Variscan amphibolite-facies metamorphism show similar Hf-O-isotope characteristics and can therefore be considered as the most probable source for the microgranite ring dyke melt. In addition, a second source with low oxygen isotope ratios (e.g. basic rocks) probably contributed to the melt and possibly triggered the climactic eruption of the Teplice rhyolite as well as the crystal-rich intrusion of the ring dyke.
Sozialraumanalyse Ginnheim : ein Frankfurter Stadtteil der Kontraste (2021)
Künstler, Falk ; Schipper, Sebastian
Prekär, flexibel, entgrenzt : Geographien der Arbeit in der "Global City" Frankfurt (2018)
Frankfurt ist Knotenpunkt globaler Güter-, Finanz-, Wissens- und Migrationsbewegungen. Die Arbeitsmärkte und -verhältnisse in der Stadt sind Ausdruck einer globalen Verwobenheit, die diskursiv oft mit dem Label der ›Global City‹ markiert wird. In einer Zeit, in der Arbeit als Feld der Produktion und Reproduktion weitreichenden Transformationsprozessen ausgesetzt ist, in der das sogenannte Normalarbeitsverhältnis zunehmend erodiert, in der Arbeitsverhältnisse oft räumlich, sozial und zeitlich entgrenzt und flexibilisiert sind und in der gut bezahlte Jobs und schlecht- bezahlte, teils prekarisierte Formen der Beschäftigung koexistieren – zum Teil im gleichen Betrieb –, muss es Aufgabe wirtschaftsgeographischer Forschung sein, die Lebenswelten von Arbeitenden in einer räumlichen Perspektive zu beleuchten. Genau dies will der vorliegende Band tun. Er versammelt engagierte, theoretisch gesättigte und empirisch geerdete Beiträge von Studierenden des Instituts für Humangeographie, die einen kritischen Blick auf die Formen, Praktiken, Beziehungen und gesellschaftliche Einbettung von Arbeit in unterschiedlichen Branchen in der ›Global City‹ Frankfurt werfen.
Wohnungs‐ und Büroimmobilienmärkte unter Stress: Deregulierung, Privatisierung und Ökonomisierung (2009)
Spatiotemporal discharge variability of the Doce river in SE Brazil during MIS 6 and 5 (2022)
Arndt, Iris ; Voigt, Silke ; Petschick, Rainer ; Hou, Alicia ; Raddatz, Jacek ; Albuquerque, Ana Luiza S. ; Bahr, André
The modern precipitation balance in southeastern (SE) Brazil is regulated by the South American summer Monsoon and threatened by global climate change. On glacial-interglacial timescales, monsoon intensity was strongly controlled by precession-forced changes in insolation. To date, relatively little is known about the spatiotemporal distribution of tropical precipitation in SE Brazil and the resulting variability of fluvial discharge on glacial-interglacial timescales. Here, we present X-ray diffraction-derived mineralogical data for the 150–70 ka period (marine isotope stage (MIS) 6 to MIS 5) from the Doce River basin. This area was sensitive to changes in monsoonal precipitation intensity due to its proximity to the South Atlantic Convergence Zone. The data, obtained from a marine sediment core (M125-55–7) close to the Doce river mouth (20°S), show pronounced changes in the Doce River suspension load’s mineralogical composition on glacial-interglacial and precessional timescales. While the ratio of silicates to carbonates displays precession-paced changes, the mineralogical composition of the carbonate-free fraction discriminates between two assemblages which strongly vary between glacial and interglacial time scales, with precession-forced variability only visible in MIS 5. The first assemblage, dominated by high contents of kaolinite and gibbsite, indicates intensified lowland erosion of mature tropical soils. The second one, characterized by higher contents of the well-ordered illite, quartz and albite, points to intensified erosion of immature soils in the upper Doce Basin. High kaolinite contents in the silicate fraction prevailed in late MIS 6 and indicate pronounced lowland soil erosion along a steepened topographic gradient. The illite-rich mineral assemblage was more abundant in MIS 5, particularly during times of high austral summer insolation, indicating strong monsoonal rainfall and intense physical erosion in the upper catchment. When the summer monsoon weakened in times of lower insolation, the mineral assemblage was dominated by kaolinite again, indicative of lower precipitation and runoff in the upper catchment and dominant lowland erosion.
Snow representation over Siberia in operational seasonal forecasting systems (2022)
Risto, Danny ; Fröhlich, Kristina ; Ahrens, Bodo
Seasonal forecasting systems still have difficulties predicting temperature over continental regions, while their performance is better over some maritime regions. On the other hand, the land surface is a substantial source of (sub-)seasonal predictability. A crucial land surface component in focus here is the snow cover, which stores water and modulates the surface radiation balance. This paper’s goal is to attribute snow cover seasonal forecasting biases and lack of skill to either initialization or parameterization errors. For this purpose, we compare the snow representation in five seasonal forecasting systems (from DWD, ECMWF, Météo-France, CMCC, and ECCC) and their performances in predicting snow and 2-m temperature over a Siberian region against ERA5 reanalysis and station data. Although all systems use similar atmospheric and land initialization approaches and data, their snow and temperature biases differ in sign and amplitude. Too-large initial snow biases persist over the forecast period, delaying and prolonging the melting phase. The simplest snow scheme (used in DWD’s system) shows too-early and fast melting in spring. However, systems including multi-layer snow schemes (Météo-France and CMCC) do not necessarily perform better. Both initialization and parameterization are causes of snow biases, but, depending on the system, one can be more dominant.
Tracing the mobility of a Late Epigravettian (~ 13 ka) male infant from Grotte di Pradis (Northeastern Italian Prealps) at high-temporal resolution (2022)
Lugli, Federico ; Nava, Alessia ; Sorrentino, Rita ; Vazzana, Antonino ; Bortolini, Eugenio ; Oxilia, Gregorio ; Silvestrini, Sara ; Nannini, Nicola ; Bondioli, Luca ; Fewlass, Helen ; Talamo, Sahra ; Bard, Edouard ; Mancini, Lucia ; Müller, Wolfgang ; Romandini, Matteo ; Benazzi, Stefano
We present the results of a multi-disciplinary investigation on a deciduous human tooth (Pradis 1), recently recovered from the Epigravettian layers of the Grotte di Pradis archaeological site (Northeastern Italian Prealps). Pradis 1 is an exfoliated deciduous molar (Rdm2), lost during life by an 11–12-year-old child. A direct radiocarbon date provided an age of 13,088–12,897 cal BP (95% probability, IntCal20). Amelogenin peptides extracted from tooth enamel and analysed through LC–MS/MS indicate that Pradis 1 likely belonged to a male. Time-resolved 87Sr/86Sr analyses by laser ablation mass spectrometry (LA-MC-ICPMS), combined with dental histology, were able to resolve his movements during the first year of life (i.e. the enamel mineralization interval). Specifically, the Sr isotope ratio of the tooth enamel differs from the local baseline value, suggesting that the child likely spent his first year of life far from Grotte di Pradis. Sr isotopes are also suggestive of a cyclical/seasonal mobility pattern exploited by the Epigravettian human group. The exploitation of Grotte di Pradis on a seasonal, i.e. summer, basis is also indicated by the faunal spectra. Indeed, the nearly 100% occurrence of marmot remains in the entire archaeozoological collection indicates the use of Pradis as a specialized marmot hunting or butchering site. This work represents the first direct assessment of sub-annual movements observed in an Epigravettian hunter-gatherer group from Northern Italy.
Implementing bicycle-friendly transport policies: Examining the effect of an infrastructural intervention on residents’ perceived quality of urban life in Frankfurt, Germany (2022)
Lanzendorf, Martin ; Scheffler, Clara ; Trost, Laura ; Werschmöller, Simon
In recent years, many European cities have developed strategies to improve the quality of urban life by reducing car traffic and increasing the attractiveness of alternative modes and the built environment for residents. Frequently, at least in German cities, improvements to the cycling infrastructures play a key role in this transformation of urban spaces. One of those transformative interventions took place in 2020 in Frankfurt am Main (Germany). The city redesigned an arterial road close to the city centre, the Friedberger Landstrasse, by converting two car lanes to bicycle lanes. It is the aim of this study to analyse the effects of this change on the quality of urban life of its residents using a quantitative before-and-after study. The results demonstrate the expected improvements in the perceived quality of urban life for residents after the intervention. A more detailed analysis, however, shows that the residents’ perceptions vary according to their own mode use on the Friedberger Landstrasse and other sociodemographic characteristics. Thus, better cycling infrastructure does not only improve conditions for cyclists, but also contributes to a higher quality of urban life for residents and, therefore, improves the liveability of a city in two ways. We conclude that local transport policies are not only relevant for a modal shift, but also for the quality of urban life and, thus, related urban development strategies.
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