TY - JOUR A1 - Ben Nsir, Siwar A1 - Jomaa, Seifeddine A1 - Yildirim, Umit A1 - Zhou, Xiangqian A1 - D'Oria, Marco A1 - Rode, Michael A1 - Khlifi, Slaheddine T1 - Assessment of climate change impact on discharge of the lakhmass catchment (Northwest Tunisia) JF - Water N2 - The Mediterranean region is increasingly recognized as a climate change hotspot but is highly underrepresented in hydrological climate change studies. This study aims to investigate the climate change effects on the hydrology of Lakhmass catchment in Tunisia. Lakhmass catchment is a part of the Medium Valley of Medjerda in northwestern Tunisia that drains an area of 126 km(2). First, the Hydrologiska Byrans Vattenbalansavdelning light (HBV-light) model was calibrated and validated successfully at a daily time step to simulate discharge during the 1981-1986 period. The Nash Sutcliffe Efficiency and Percent bias (NSE, PBIAS) were (0.80, +2.0%) and (0.53, -9.5%) for calibration (September 1982-August 1984) and validation (September 1984-August 1986) periods, respectively. Second, HBV-light model was considered as a predictive tool to simulate discharge in a baseline period (1981-2009) and future projections using data (precipitation and temperature) from thirteen combinations of General Circulation Models (GCMs) and Regional Climatic Models (RCMs). We used two trajectories of Representative Concentration Pathways, RCP4.5 and RCP8.5, suggested by the Intergovernmental Panel on Climate Change (IPCC). Each RCP is divided into three projection periods: near-term (2010-2039), mid-term (2040-2069) and long-term (2070-2099). For both scenarios, a decrease in precipitation and discharge will be expected with an increase in air temperature and a reduction in precipitation with almost 5% for every +1 degrees C of global warming. By long-term (2070-2099) projection period, results suggested an increase in temperature with about 2.7 degrees C and 4 degrees C, and a decrease in precipitation of approximately 7.5% and 15% under RCP4.5 and RCP8.5, respectively. This will likely result in a reduction of discharge of 12.5% and 36.6% under RCP4.5 and RCP8.5, respectively. This situation calls for early climate change adaptation measures under a participatory approach, including multiple stakeholders and water users. KW - hydrological modeling KW - HBV-light model KW - Mediterranean KW - discharge KW - climate change KW - RCP4,5 and 8,5 Y1 - 2022 U6 - https://doi.org/10.3390/w14142242 SN - 2073-4441 VL - 14 IS - 14 PB - MDPI CY - Basel ER - TY - JOUR A1 - McCool, Weston C. A1 - Codding, Brian F. A1 - Vernon, Kenneth B. A1 - Wilson, Kurt M. A1 - Yaworsky, Peter M. A1 - Marwan, Norbert A1 - Kennett, Douglas J. T1 - Climate change-induced population pressure drives high rates of lethal violence in the Prehispanic central Andes JF - Proceedings of the National Academy of Sciences of the United States of America : PNAS N2 - Understanding the influence of climate change and population pressure on human conflict remains a critically important topic in the social sciences. Long-term records that evaluate these dynamics across multiple centuries and outside the range of modern climatic variation are especially capable of elucidating the relative effect of-and the interaction between-climate and demography. This is crucial given that climate change may structure population growth and carrying capacity, while both climate and population influence per capita resource availability. This study couples paleoclimatic and demographic data with osteological evaluations of lethal trauma from 149 directly accelerator mass spectrometry C-14-dated individuals from the Nasca highland region of Peru. Multiple local and supraregional precipitation proxies are combined with a summed probability distribution of 149 C-14 dates to estimate population dynamics during a 700-y study window. Counter to previous findings, our analysis reveals a precipitous increase in violent deaths associated with a period of productive and stable climate, but volatile population dynamics. We conclude that favorable local climate conditions fostered population growth that put pressure on the marginal and highly circumscribed resource base, resulting in violent resource competition that manifested in over 450 y of internecine warfare. These findings help support a general theory of intergroup violence, indicating that relative resource scarcity-whether driven by reduced resource abundance or increased competition-can lead to violence in subsistence societies when the outcome is lower per capita resource availability. KW - climate change KW - population pressure KW - warfare KW - lethal violence KW - Andes Y1 - 2022 U6 - https://doi.org/10.1073/pnas.2117556119 SN - 0027-8424 SN - 1091-6490 VL - 119 IS - 17 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Kong, Xiangzhen A1 - Ghaffar, Salman A1 - Determann, Maria A1 - Friese, Kurt A1 - Jomaa, Seifeddine A1 - Mi, Chenxi A1 - Shatwell, Tom A1 - Rinke, Karsten A1 - Rode, Michael T1 - Reservoir water quality deterioration due to deforestation emphasizes the indirect effects of global change JF - Water research : a journal of the International Association on Water Quality (IAWQ) N2 - Deforestation is currently a widespread phenomenon and a growing environmental concern in the era of rapid climate change. In temperate regions, it is challenging to quantify the impacts of deforestation on the catchment dynamics and downstream aquatic ecosystems such as reservoirs and disentangle these from direct climate change impacts, let alone project future changes to inform management. Here, we tackled this issue by investigating a unique catchment-reservoir system with two reservoirs in distinct trophic states (meso- and eutrophic), both of which drain into the largest drinking water reservoir in Germany. Due to the prolonged droughts in 2015-2018, the catchment of the mesotrophic reservoir lost an unprecedented area of forest (exponential increase since 2015 and ca. 17.1% loss in 2020 alone). We coupled catchment nutrient exports (HYPE) and reservoir ecosystem dynamics (GOTM-WET) models using a process-based modeling approach. The coupled model was validated with datasets spanning periods of rapid deforestation, which makes our future projections highly robust. Results show that in a short-term time scale (by 2035), increasing nutrient flux from the catchment due to vast deforestation (80% loss) can turn the mesotrophic reservoir into a eutrophic state as its counterpart. Our results emphasize the more prominent impacts of deforestation than the direct impact of climate warming in impairment of water quality and ecological services to downstream aquatic ecosystems. Therefore, we propose to evaluate the impact of climate change on temperate reservoirs by incorporating a time scale-dependent context, highlighting the indirect impact of deforestation in the short-term scale. In the long-term scale (e.g. to 2100), a guiding hypothesis for future research may be that indirect effects (e.g., as mediated by catchment dynamics) are as important as the direct effects of climate warming on aquatic ecosystems. KW - deforestation KW - climate change KW - temperate regions KW - reservoir KW - eutrophication KW - process-based modeling Y1 - 2022 U6 - https://doi.org/10.1016/j.watres.2022.118721 SN - 0043-1354 SN - 1879-2448 VL - 221 PB - Elsevier Science CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Katzenberger, Anja A1 - Levermann, Anders A1 - Schewe, Jacob A1 - Pongratz, Julia T1 - Intensification of very wet monsoon seasons in India under global warming JF - Geophysical research letters N2 - Rainfall-intense summer monsoon seasons on the Indian subcontinent that are exceeding long-term averages cause widespread floods and landslides. Here we show that the latest generation of coupled climate models robustly project an intensification of very rainfall-intense seasons (June-September). Under the shared socioeconomic pathway SSP5-8.5, very wet monsoon seasons as observed in only 5 years in the period 1965-2015 are projected to occur 8 times more often in 2050-2100 in the multi-model average. Under SSP2-4.5, these seasons become only a factor of 6 times more frequent, showing that even modest efforts to mitigate climate change can have a strong impact on the frequency of very strong rainfall seasons. Besides, we find that the increasing risk of extreme seasonal rainfall is accompanied by a shift from days with light rainfall to days with moderate or heavy rainfall. Additionally, the number of wet days is projected to increase. KW - Indian monsoon KW - climate modeling KW - extreme seasons KW - climate change KW - CMIP6 KW - India Y1 - 2022 U6 - https://doi.org/10.1029/2022GL098856 SN - 0094-8276 SN - 1944-8007 VL - 49 IS - 15 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Kuhla, Kilian A1 - Willner, Sven N. A1 - Otto, Christian A1 - Geiger, Tobias A1 - Levermann, Anders T1 - Ripple resonance amplifies economic welfare loss from weather extremes JF - Environmental research letters : ERL / Institute of Physics N2 - The most complex but potentially most severe impacts of climate change are caused by extreme weather events. In a globally connected economy, damages can cause remote perturbations and cascading consequences-a ripple effect along supply chains. Here we show an economic ripple resonance that amplifies losses when consecutive or overlapping weather extremes and their repercussions interact. This amounts to an average amplification of 21% for climate-induced heat stress, river floods, and tropical cyclones. Modeling the temporal evolution of 1.8 million trade relations between >7000 regional economic sectors, we find that the regional responses to future extremes are strongly heterogeneous also in their resonance behavior. The induced effect on welfare varies between gains due to increased demand in some regions and losses due to demand or supply shortages in others. Within the current global supply network, the ripple resonance effect of extreme weather is strongest in high-income economies-an important effect to consider when evaluating past and future economic climate impacts. KW - consecutive disasters KW - economic ripple resonance KW - repercussion resonance KW - weather extremes KW - supply network KW - climate impacts KW - climate change Y1 - 2021 U6 - https://doi.org/10.1088/1748-9326/ac2932 SN - 1748-9326 VL - 16 IS - 11 PB - IOP Publ. Ltd. CY - Bristol ER - TY - JOUR A1 - Pearce, Warren A1 - Özkula, Suay M. A1 - Greene, Amanda K. A1 - Teeling, Lauren A1 - Bansard, Jennifer S. A1 - Omena, Janna Joceli A1 - Rabello, Elaine Teixeira T1 - Visual cross-platform analysis JF - Information, Communication and Society: digital methods to research social media images N2 - Analysis of social media using digital methods is a flourishing approach. However, the relatively easy availability of data collected via platform application programming interfaces has arguably led to the predominance of single-platform research of social media. Such research has also privileged the role of text in social media analysis, as a form of data that is more readily gathered and searchable than images. In this paper, we challenge both of these prevailing forms of social media research by outlining a methodology for visual cross-platform analysis (VCPA), defined as the study of still and moving images across two or more social media platforms. Our argument contains three steps. First, we argue that cross-platform analysis addresses a gap in research methods in that it acknowledges the interplay between a social phenomenon under investigation and the medium within which it is being researched, thus illuminating the different affordances and cultures of web platforms. Second, we build on the literature on multimodal communication and platform vernacular to provide a rationale for incorporating the visual into cross-platform analysis. Third, we reflect on an experimental cross-platform analysis of images within social media posts (n = 471,033) used to communicate climate change to advance different modes of macro- and meso-levels of analysis that are natively visual: image-text networks, image plots and composite images. We conclude by assessing the research pathways opened up by VCPA, delineating potential contributions to empirical research and theory and the potential impact on practitioners of social media communication. KW - research methodology KW - visual analysis KW - social media KW - climate change Y1 - 2018 U6 - https://doi.org/10.1080/1369118X.2018.1486871 SN - 1468-4462 SN - 1369-118X VL - 23 IS - 2 SP - 161 EP - 180 PB - Routledge CY - London ER - TY - JOUR A1 - Palmer, Matthew D. A1 - Gregory, Jonathan A1 - Bagge, Meike A1 - Calvert, Daley A1 - Hagedoorn, Jan Marius A1 - Howard, Tom A1 - Klemann, Volker A1 - Lowe, Jason A. A1 - Roberts, Chris A1 - Slangen, Aimee B. A. A1 - Spada, Giorgio T1 - Exploring the drivers of global and local sea‐level change over the 21st century and beyond JF - Earth's future N2 - We present a new set of global and local sea‐level projections at example tide gauge locations under the RCP2.6, RCP4.5, and RCP8.5 emissions scenarios. Compared to the CMIP5‐based sea‐level projections presented in IPCC AR5, we introduce a number of methodological innovations, including (i) more comprehensive treatment of uncertainties, (ii) direct traceability between global and local projections, and (iii) exploratory extended projections to 2300 based on emulation of individual CMIP5 models. Combining the projections with observed tide gauge records, we explore the contribution to total variance that arises from sea‐level variability, different emissions scenarios, and model uncertainty. For the period out to 2300 we further breakdown the model uncertainty by sea‐level component and consider the dependence on geographic location, time horizon, and emissions scenario. Our analysis highlights the importance of local variability for sea‐level change in the coming decades and the potential value of annual‐to‐decadal predictions of local sea‐level change. Projections to 2300 show a substantial degree of committed sea‐level rise under all emissions scenarios considered and highlight the reduced future risk associated with RCP2.6 and RCP4.5 compared to RCP8.5. Tide gauge locations can show large ( > 50%) departures from the global average, in some cases even reversing the sign of the change. While uncertainty in projections of the future Antarctic ice dynamic response tends to dominate post‐2100, we see substantial differences in the breakdown of model variance as a function of location, time scale, and emissions scenario. KW - climate change KW - CMIP5 models KW - RCP scenarios KW - sea-level projections KW - tide gauge observations Y1 - 2020 U6 - https://doi.org/10.1029/2019EF001413 SN - 2328-4277 VL - 8 IS - 9 SP - 1 EP - 25 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Leins, Johannes A. A1 - Grimm, Volker A1 - Drechsler, Martin T1 - Large-scale PVA modeling of insects in cultivated grasslands BT - the role of dispersal in mitigating the effects of management schedules under climate change JF - Ecology and evolution N2 - In many species, dispersal is decisive for survival in a changing climate. Simulation models for population dynamics under climate change thus need to account for this factor. Moreover, large numbers of species inhabiting agricultural landscapes are subject to disturbances induced by human land use. We included dispersal in the HiLEG model that we previously developed to study the interaction between climate change and agricultural land use in single populations. Here, the model was parameterized for the large marsh grasshopper (LMG) in cultivated grasslands of North Germany to analyze (1) the species development and dispersal success depending on the severity of climate change in subregions, (2) the additional effect of grassland cover on dispersal success, and (3) the role of dispersal in compensating for detrimental grassland mowing. Our model simulated population dynamics in 60-year periods (2020-2079) on a fine temporal (daily) and high spatial (250 x 250 m(2)) scale in 107 subregions, altogether encompassing a range of different grassland cover, climate change projections, and mowing schedules. We show that climate change alone would allow the LMG to thrive and expand, while grassland cover played a minor role. Some mowing schedules that were harmful to the LMG nevertheless allowed the species to moderately expand its range. Especially under minor climate change, in many subregions dispersal allowed for mowing early in the year, which is economically beneficial for farmers. More severe climate change could facilitate LMG expansion to uninhabited regions but would require suitable mowing schedules along the path. These insights can be transferred to other species, given that the LMG is considered a representative of grassland communities. For more specific predictions on the dynamics of other species affected by climate change and land use, the publicly available HiLEG model can be easily adapted to the characteristics of their life cycle. KW - bilinear interpolation KW - climate change KW - dispersal success KW - land use KW - large marsh grasshopper KW - spatially explicit model Y1 - 2022 U6 - https://doi.org/10.1002/ece3.9063 SN - 2045-7758 VL - 12 IS - 7 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Huber, Veronika A1 - Krummenauer, Linda A1 - Peña-Ortiz, Cristina A1 - Lange, Stefan A1 - Gasparrini, Antonio A1 - Vicedo-Cabrera, Ana Maria A1 - Garcia-Herrera, Ricardo A1 - Frieler, Katja T1 - Temperature-related excess mortality in German cities at 2 °C and higher degrees of global warming JF - Environmental Research N2 - Background: Investigating future changes in temperature-related mortality as a function of global mean temperature (GMT) rise allows for the evaluation of policy-relevant climate change targets. So far, only few studies have taken this approach, and, in particular, no such assessments exist for Germany, the most populated country of Europe. Methods: We assess temperature-related mortality in 12 major German cities based on daily time-series of all-cause mortality and daily mean temperatures in the period 1993-2015, using distributed-lag non-linear models in a two-stage design. Resulting risk functions are applied to estimate excess mortality in terms of GMT rise relative to pre-industrial levels, assuming no change in demographics or population vulnerability. Results: In the observational period, cold contributes stronger to temperature-related mortality than heat, with overall attributable fractions of 5.49% (95%CI: 3.82-7.19) and 0.81% (95%CI: 0.72-0.89), respectively. Future projections indicate that this pattern could be reversed under progressing global warming, with heat-related mortality starting to exceed cold-related mortality at 3 degrees C or higher GMT rise. Across cities, projected net increases in total temperature-related mortality were 0.45% (95%CI: -0.02-1.06) at 3 degrees C, 1.53% (95%CI: 0.96-2.06) at 4 degrees C, and 2.88% (95%CI: 1.60-4.10) at 5 degrees C, compared to today's warming level of 1 degrees C. By contrast, no significant difference was found between projected total temperature-related mortality at 2 degrees C versus 1 degrees C of GMT rise. Conclusions: Our results can inform current adaptation policies aimed at buffering the health risks from increased heat exposure under climate change. They also allow for the evaluation of global mitigation efforts in terms of local health benefits in some of Germany's most populated cities. KW - temperature-related mortality KW - climate change KW - Future projections KW - Germany KW - global mean temperature Y1 - 2020 U6 - https://doi.org/10.1016/j.envres.2020.109447 SN - 0013-9351 SN - 1096-0953 VL - 186 SP - 1 EP - 10 PB - Elsevier CY - San Diego, California ER - TY - JOUR A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Pestryakova, Luidmila Agafyevna A1 - Epp, Laura Saskia A1 - Herzschuh, Ulrike T1 - Phylogenetic diversity and environment form assembly rules for Arctic diatom genera BT - a study on recent and ancient sedimentary DNA JF - Journal of Biogeography N2 - Aim This study investigates taxonomic and phylogenetic diversity in diatom genera to evaluate assembly rules for eukaryotic microbes across the Siberian tree line. We first analysed how phylogenetic distance relates to taxonomic richness and turnover. Second, we used relatedness indices to evaluate if environmental filtering or competition influences the assemblies in space and through time. Third, we used distance-based ordination to test which environmental variables shape diatom turnover. Location Yakutia and Taymyria, Russia: we sampled 78 surface sediments and a sediment core, extending to 7,000 years before present, to capture the forest-tundra transition in space and time respectively. Taxon Arctic freshwater diatoms. Methods We applied metabarcoding to retrieve diatom diversity from surface and core sedimentary DNA. The taxonomic assignment binned sequence types (lineages) into genera and created taxonomic (abundance of lineages within different genera) and phylogenetic datasets (phylogenetic distances of lineages within different genera). Results Contrary to our expectations, we find a unimodal relationship between phylogenetic distance and richness in diatom genera. We discern a positive relationship between phylogenetic distance and taxonomic turnover in spatially and temporally distributed diatom genera. Furthermore, we reveal positive relatedness indices in diatom genera across the spatial environmental gradient and predominantly in time slices at a single location, with very few exceptions assuming effects of competition. Distance-based ordination of taxonomic and phylogenetic turnover indicates that lake environment variables, like HCO3- and water depth, largely explain diatom turnover. Main conclusion Phylogenetic and abiotic assembly rules are important in understanding the regional assembly of diatom genera across lakes in the Siberian tree line ecotone. Using a space-time approach we are able to exclude the influence of geography and elucidate that lake environmental variables primarily shape the assemblies. We conclude that some diatom genera have greater capabilities to adapt to environmental changes, whereas others will be putatively replaced or lost due to the displacement of the Arctic tundra biome under recent global warming. KW - ancient sedimentary DNA KW - Arctic lakes KW - assembly rules KW - climate change KW - diatoms KW - environmental filtering KW - phylogenetic diversity KW - Siberian tree line Y1 - 2020 U6 - https://doi.org/10.1111/jbi.13786 SN - 0305-0270 SN - 1365-2699 VL - 47 IS - 5 SP - 1166 EP - 1179 PB - Wiley-Blackwell CY - Oxford ER -