Chemical weathering is a central biogeochemical process that shapes the Earth’s Critical Zone (CZ), regulates the global carbon cycle and sets the pace for nutrient delivery to soils and ecosystems. Most knowledge on the rates and controls on chemical weathering are from laboratory experiments and from the short-term observation of modern soil and river systems. In contrast, little is known about past changes of chemical weathering over hundreds to thousands of years, which limits our understanding of how long-lasting human-climate-ecosystem interactions have impacted the CZ trajectories. Because of this knowledge gap, it is not possible to fully understand the response and feedbacks of the CZ to the climatic and environmental perturbations of the Holocene period, nor to predict their future evolution during the Anthropocene. To fill this gap, LAKE-SWITCH aims to produce new quantitative weathering records over 10^2-10^4 year timescales, with a temporal focus on the Holocene period. There are 3 main challenges: 1) developing quantitative proxies of chemical weathering, 2) calibrating these proxies for paleo-reconstructions, 3) measuring these proxies in paleo-archives of 10^2-10^4 year timescale integration. To provide these records, we will measure lithium and strontium isotopic proxies in lake detrital and authigenic – carbonates and biogenic silica – sediment archives. To calibrate these proxies and archives, we will use a source-to-sink approach and track weathering product pathways from soils, through rivers, to lake deposits. Then we will apply these proxies back in time in Holocene lake cores. As rapidly-eroding mountain dominate the global chemical erosion budget, we will focus on the study of the European Alps. New data from Alpine watersheds and lake records spanning gradients in erosion, runoff and land use will serve to quantify and model the impact of climate and human drivers on soil trajectories from the onset of the Holocene to the Anthropocene.

This project aims at better understanding the impact of the climate change on the morphologic and environmental processes in the Mont-Blanc Massif (MBM), with particular focus on the reduction of glacier surface-area, rock-fall increase related to permafrost warming and downstream changes of water and sediments fluxes. Adequately tackling the environmental and societal challenges arising from the acceleration of these processes requires 1) a documentation of the spatio-temporal evolution of each component, i.e. local climate, rock faces, glaciers, sediment production and hydrological regimes; and 2) an understanding of the complex interactions between these components. To address the two issues, we formed a team of climatologists, geomorphologists, glaciologists, permafrost specialists and hydrologists that will perform a systemic approach within five work-packages. The first one is dedicated to the coordination aspects; the other four focus on the study of the spatio-temporal changes of the different components influencing the evolution of the MBM: climate, hydrology, permafrost, erosion products, and present-day and Holocene glacier dynamics. In order to investigate the complex interplay between these parameters, active exchange between work-packages will assure cross-analysis of the resulting data. The project is based on both observations (field measurements, remote sensing and geochemistry) and modeling. Direct field observations will benefit from: 1) the contributions of the GLACIOCLIM observatory (LGGE-LTHE) regarding the glacio-hydrological processes; 2) the expertise of the EDYTEM lab in permafrost studies, and 3) the one of the ISTerre lab in erosional processes. Climate modeling will be handled by the “Centre de Recherche de Climatologie” of BioGeoscience. Remote sensing will benefit from the expertise of the LISTIC in satellite image processing while the study of long-term glacial and peri-glacial processes will be based on cosmogenic nuclides, including notably the new in-situ produced 14C dating tool currently implemented at CEREGE. Several modeling will be applied for the present-day (last ~50 years) period: the 1979-today regional climate variability around the MBM will first be analyzed through kilometer-scale numerical climate modeling and compared with statistically downscaled fields derived from atmospheric re-analyses and general circulation models. In addition to climate analysis (mostly focused on local orographic effects), the derived high-resolution data will be used to feed hydrological, permafrost and glacier models. Glacio-hydrological model will rely on a degree-day modeling. Glacier modeling will be based on functions linking mass balance and surface elevation changes, thermal evolution of the permafrost on physical modeling of rock surface temperature distribution, and sub-glacial erosion will be estimated as a function of the basal-ice velocity. Glacier fluctuations, including glacier retreat during the warm periods of the Holocene, will be studied using in-situ produced cosmogenic nuclides (14C and 10Be). An erosion/ice cover history will be deduced from modeled glacier mass balance and sub-glacial erosion functions will be calibrated with the present-day period and forced by different Holocene climate scenarii. Projections of future environmental evolutions will be achieved through a statistical downscaling of climate change simulations using the most recent IPCC scenarii. The reliability of the regionalized climate will be evaluated through comprehensive comparisons with observations under present conditions before applying the downscaling technique to a multi-model, multi-scenario (RCP2.6 and 8.5 radiative forcings) ensemble of global climate models throughout the 21st century. Projection of the glacier extents and permafrost changes till at least the mid-21st century will be statistically deduced from the multi-scenario climatic ensemble applied to the mass balance and thermal models.

The SCHEMA project aims to study archaeological sites that have received relatively little scientific attention, even though they constitute one of the largest corpus of European rock art: Holocene schematic rock art sites. The non-figurative nature of this art, its poor preservation and the difficulty of dating it directly (mineral pigments) explain this lesser scientific investment. However, the schematism of this graphic expression directly questions the cognitive processes that gave rise to it and, in so doing, questions its role within post-pleistocene prehistoric societies. This schematic rock art thus constitutes an essential vector of information about prehistoric societies that complements the other archaeological remains. In order to remove the analytical barriers identified, the SCHEMA project proposes a new research method, based on an integrated approach to the sites, combining data from archaeology, archaeo-geomorphology and materials science. The essence of the project is the construction of a methodology designed to apprehend as accurately as possible the graphic syntaxes of the schematic art of southern France, which can eventually be mobilised to question its cognitive nature. This is based on (i) an optimal recording of the sites (3D, Dstretch, hypspectral imagery); (ii) the characterisation of the nature and origin of the empty spaces of the decorated walls (WP2); (iii) the characterisation of the different temporalities of the walls (WP3). These work packages mobilise specific analyses but also common ones to reinforce the convergence of results (3D imaging, hyperspectral imaging, physico-chemical analyses, etc.). The results acquired will enable the graphic representations, visible and invisible, to be placed in the space of the wall and the site and in the time of their creation. These results will then allow us to approach the figurative syntaxes characteristic of this schematic rock art, the construction of the schematic discourse (WP4). Furthermore, the whole of this operating chain will produce original cartographies of the walls and sites studied, integrating the modes of representation, the pictorial matter used, the state of the walls and the chronological settings. Given the singularity of this rock art, which is relatively unknown in France, the SCHEMA project aims (i) to develop exchanges between researchers of different nationalities and specialists in schematic rock art; (ii) to promote the results of the project to the scientific community, the general public and local authorities in order to raise awareness of the heritage value of schematic rock art sites (see WP5). In this context, the results of the project will contribute to the next permanent exhibition of the Prehistory Museum of the Gorges du Verdon. Through this renewed methodology mobilising new analysis tools, the SCHEMA project aims to achieve a better understanding of the functioning, nature and social practices associated with schematic rock art. More broadly, we believe that the methodological and conceptual contribution of this project goes beyond the simple study of schematic art. Indeed, a large number of the world's rock art sites are located in open-air spaces that encounter the same issues of preservation, reading (alteration of the visibility of the figures, etc.) and chronological setting. The integrated and analytical approach developed in SCHEMA can enrich the research carried out on other chrono-cultural contexts.

Perennially frozen slopes occur in many mountain ranges of the world, and temperature changes in these environments have notable impacts on the state of permafrost, leading to increased slope instability and hazard from mass movements. In areas of discontinuous permafrost, these slopes can be hard to identify with certainty. This project investigates “molards” – cones of loose debris that result from thawing of blocks of ice-rich sediments mobilised by landslides in permafrost terrains. Molards are an understudied landform and have recently been shown to be an indicator of recent and ongoing permafrost degradation. In addition, they have spatial and geomorphic characteristics that reveal the dynamics of large mass movements. The PERMOLARDS project aims to build on these exciting new results and use molards as a geomorphological tool to understand climate change and natural hazard. We will use a multidisciplinary combination of field investigation, dating, laboratory and numerical simulations, modelling and remote sensing analysis to understand molard formation, evolution, morphology, longevity, and their environmental settings. We will explore three unique case studies in Greenland, Canada and Iceland, where we have identified with certainty molards that formed under climatic conditions from the Holocene to the present in a variety of geographic settings. We will constrain the morphological degradation of molards in space and time by using a morphological approach and novel luminescence dating techniques. We will define the range of material properties and ice configurations under which molards can form through field investigations and through simulation via analogue models in a laboratory cold room. Based on these results ancient molards can then be used to infer ground-ice contents. We will establish the baseline criteria to distinguish molards from other mounds in landslide deposits using remote sensing and field data that can be used by other researchers. We will use 3D numerical models to assess the potential role of thaw fluids in molard-hosting landslides in modifying the flow behaviour and its impact on hazard. We will monitor and model the state of permafrost at the field site in Greenland to ascertain the state of permafrost degradation represented by molards in new and recent landsides. Finally, we will establish the use of molards as a geomorphological tool to track permafrost degradation in time and in different geological and geographical settings around the globe. By developing these actions, the project provides insights into permafrost degradation in space and time, and the hazard posed by landslides in cold environments.

COSMO-ART proposes a new methodology based on a Cosmopolitan Approach to assess common interest points in uses and perceptions of rock art sites so as to articulate perceptions and development policies and better fulfil requirements of sustainability. This methodology has been elaborated by consortium members in the Maloti-Drakensberg WHS (South Africa-Lesotho) and COSMO-ART intends now to test its transferability by investigating 2 other regions: 1/ the Kimberley area, South Africa and 2/ the Erongo massif, Namibia. This cosmopolitan approach requires designing a systemic, diachronic and interdisciplinary methodology, combining contributions of archaeology, history, museography, human and social geography, environmental and cultural anthropology, geomorphology, and materials science. The project is split into 3 interdependent WP: 1/ Uses and values of rock art sites; 2/ Tourist activities and public presentation; 3/ Vulnerabilities and mitigation strategies.