1. Quaternary paleoenvironments of southern Africa
This session examines the evidence for, and implications of, environmental change across Africa on multi-decadal to multi-millennial timescales. Spanning the equator and encompassing tropical, subtropical and temperate climate systems of both hemispheres, Africa provides a unique opportunity to study not only local and regional climate dynamics but also inter- and intrahemispheric linkages in the global climate system. However, in comparison with much of the rest of the world, there is relatively little known about how African climates have changed in the past and why. This interdisciplinary session seeks to make connections between researchers working in Africa and highlight new records, proxies and syntheses that address existing knowledge gaps at both regional and continental scales.
2. The last interglacial
The last interglacial (LIG, marine isotope stage 5e) has an increasing attraction for paleoclimate study. While not an analogue for the future at global scale, the raised sea level that has been deduced demands that we understand how the increased polar temperatures affected the Antarctic and Greenland Ice Sheets. The LIG is characterized by a large contrast in insolation compared to the Holocene, and its start exhibits a very different dynamic that probably holds clues to the way that AMOC interacts with glacial terminations. Increasing amounts of well-resolved data are becoming available although dating remains a challenge. New experiments, both 127-ka snapshots and transient, were carried out within the auspices of PMIP, and the results should be available for the OSM. In this session, we invite presentations on all aspects of the LIG, including its start, end, comparisons with other interglacial periods, and the extent to which it can inform us about our future.
3. New developments in speleothem paleoclimate and paleoenvironmental science
Over the last two decades, speleothems have been increasingly applied for past climatic and environmental reconstructions for the last ca. 500 thousand years using the U-Th absolute dating method. However, recent improvements in the U-Pb dating methodology have already demonstrated that speleothem paleoclimate timeseries can be extended further back in time. Oxygen and carbon stable isotopes (δ18O and δ13C) are the most exploited measurements, allowing the investigation of an array of past climate and environmental variables such as temperature, rainfall amount, moisture provenance, and seasonality. Trace elements, clumped isotopes, and fluid inclusions are among the newest climate proxies being progressively applied to refine the speleothem-based paleoclimatic interpretations and to gain novel insights into past climatic and environmental dynamics. With the aim of presenting the most recent findings and advancements, this session welcomes speleothem-based paleoclimate and paleoenvironmental studies. We give special attention to records from underrepresented regions and/or time periods, as well as to novel approaches and/or techniques. We also welcome studies involving data-model comparisons, both using climate models as well as proxy system and karst geochemical models.
4. Social geosciences: Community-needs-driven paleo research for building sustainable and resilient societies
Under accelerating anthropogenic climate change scenarios and ever-increasing human environmental pressures, society today faces unprecedented challenges related to sustainable management of its limited natural resources and ensuring equitable access to those resources for all communities. It is clear that in the coming decades, our ability to effectively address and provide critical information regarding some of the most pressing human-environment issues, such as water security, food security, public health, land preservation and management within existing social frameworks (i.e. gender, class, ethnicity/castes, employment and migration, etc.) that usually manifest at local and regional scales, will necessitate a paradigm shift in the Earth systems sciences, in which, the human society is viewed and understood as an active player of the Earth system (i.e. the human beings impact the environment and are in turn impacted by environmental changes). This new paradigm shift can only be achieved via enhanced partnership between natural scientists and social scientists and, most importantly, where field practitioners and environmental planners, who work with at-risk local communities, are able to both inform research directions and questions that are human-needs focused as well as are able to communicate the results of the collaborative research back to the community in an effective manner (engaged research). In fostering such a stakeholder-focused, collaborative, and "engaged research" space, geoscientists, particularly those whose research focuses on environmental and climate records of the Anthropocene (and late Holocene), could play a key role by developing tools, methods, and most importantly, by providing relevant, high-resolution historical records of variations and changes in climate, environment and ecosystems at regional and local scales. Extensive data on local and regional environmental change can allow social scientists to understand environmental changes in the context of existing social norms, market mechanisms, agro-environmental policy and public attitudes. The co-development, conduct and outcome of such stake-holder focused research can also help fill the knowledge gap in vulnerable local communities, potentially making communities more resilient to climate and environmental change, especially in developing countries, where weak institutions and public distrust are major hindrances to effectiveness of public policy.
To start building such a stakeholder-focused collaborative research space, we invite contributions from scientists and practitioners working at the interface of paleoscience, social science and community engagement. We seek contributions from the paleo research community that are collaborative, applied, and human-needs focused. We especially encourage contributions that:
(1) provide historical records of climate, environmental or ecosystem change relevant for understanding environmental issues faced by local communities, environmental planners and policy makers,
(2) generate tools and techniques necessary for developing high-resolution records that are relevant for addressing social and economic issues faced by stake-holders,
(3) provide records that improve benchmarking of local downscaling and validation,
(4) enhance the visibility and utility of paleo research to the policy makers and vulnerable communities,
(5) improve public access to paleoscientific data, or
(6) broaden participation in paleoscience research by community members and stakeholders.
Via this session, we aim to bring together social-minded paleoscientists who are working to improve our collective ability to understand how paleo research can provide critical information that will allow us to manage our natural resources, improve access to resources in an equitable and sustainable manner, and address socio-economic and political aspects of human decision-making in the face of 21st century climate and environmental risks.
5. From the LGM to the Anthropocene: Environmental changes driven by climatic variability and human activity in East Asia
This multidisciplinary session will showcase the diverse climate and environmental change research across the various terrestrial environments of East Asia. East Asia is a highly dynamic region that underwent important environmental changes since the Last Glacial Maximum (LGM). The region has a long and complex history of human migration and land-use changes that modified the landscape and supported various ancient civilizations. Additionally, this region supports a large array of high-quality archives (i.e. lakes, peatlands, loess, marine sediments, etc.) recording paleoenvironmental changes. The ability to distinguish natural from anthropogenic change in environmental archives is increasingly important for understanding how these ecosystems have functioned in the past and will function in the future. We aim to bring together recent advances in paleoclimatic, paleoenvironmental, and human-activity reconstructions that contribute to understanding past climatic variability and human-climate-environment interactions in East Asia. Contributions related to, but not limited to, the following topics are welcome:
- terrestrial and near-shore records (peat bogs, lakes sediments, speleothems, marine/estuarine sediments, etc.) of climate variability at decadal to millennial timescales;
- studies of human responses to past climate change and human impacts on natural environments; and
- environmental impacts of past climate changes and human activities including vegetation dynamics, biogeochemical cycle of elements, and hydrological fluctuations.
Contributions that explore new analytical techniques, combine proxy records with historical evidences and/or larger-scale studies based on paleoenvironmental and archaeological database are particularly encouraged.
6. Sedimentary varves: High-resolution archives of past climate and environmental change
Annually laminated (i.e. varved) sediments are found in many diverse lacustrine and marine settings across the globe. They provide high-resolution sedimentary records with incremental time control in absolute years and offer precise timeseries of biological, stable and radiogenic isotopic, geochemical and sedimentological parameters.
Their analysis can yield climate reconstructions linked to e.g. hydroclimatic conditions, precipitation, temperature, modes of climate variability, and exogenic forcings. Varves can document environmental and ecological responses to rapid climate changes occurring on human timescales. It is possible to identify stratigraphic isochrons such as tephra layers and peaks in cosmogenic radionuclides in varved sediments, which allow for independent validation of varve chronologies and precise (year-to-year) synchronization of records obtained from different climatic regions, enabling scientists to better understand spatial gradients over time and to test regional climate models. This session is aimed at a multidisciplinary audience of sedimentologists, paleolimnologists, paleoecologists and paleoclimate modelers using varves from different environments to examine changes from millennial to subannual temporal scales. We welcome papers related to climate reconstruction and climate impact on aquatic environments. Moreover, we invite abstracts about developments in the interpretation of varves and improvements in geochronology, as well as new analytical techniques. This session is a contribution to the Varves Working Group, which is a PAGES endorsed group.
7. Charting future pathways to sustainability using concepts of resilience and adaptation
Concepts of sustainability and resilience, which underpin many of the future challenges and the instruments used to try and chart change and future routes, are embedded in time. As such, the assessment of these concepts requires the inclusion of a temporal perspective; specifically in sustainability agendas where paleoscience needs to provide more tangible contributions. However, there are multiple challenges to forge the link between paleoscience and application! One of the key challenges in the face of changing climates and growing and developing populations is how to create, conserve, and restore environments and landscapes that meet the needs of people, at the same time as safeguarding biodiversity and ecosystem services, and retaining adaptive capacity. This challenge requires an interdisciplinary approach to understand the interplay, trade-offs, and complexities of competing human and biological imperatives. In the face of this complexity, examining past variability can help in defining realistic future scenarios and in shaping ecosystem management that builds resilience and sustainable ecosystem services. But over what spatial and temporal scales? Bringing evidence from which proxy, or which suite of proxies? How to convey uncertainty and at what spatial scale?
These are all questions that the paleo community must face as they strive to make their work policy-relevant. There is another whole suite of questions about how can these paleodata be presented to non-paleoscientists with a focus on contemporary environmental and societal challenges. Finding answers to these questions is particularly challenging, given the diverse range of users from the research community and global assessments such as the IPCC or IPBES, to local, national, and regional managers and decision-makers. In this session, we consider how a past-present-future perspective can contribute to biodiversity conservation and sustainability in a changing world. We aim to run the session in two parts. Firstly, there will be a series of presentations from people leading in some of the challenges raised above. Secondly, we propose to have an open "parliamentary debate" where a series of binary questions will be debated by the audience with people able to take sides of the "house" where they will have the opportunity to present their perspectives and persuade people to move to their side of the house.
8. Recent paleoclimate research advances in the Americas over the Common Era
Our understanding of past climate variability and change in the Americas has made significant progress over the past decade, thanks to new analytical techniques, improved data coverage in space and time, and advances in proxy development, modeling, and our understanding of climate sensitivity of different proxies. Nonetheless, many challenges remain. This session seeks to synthesize the latest advances in paleoclimate research over the Americas during the Common Era (past 2000 years), with a special focus on South America, where sampling is still limited. We encourage contributions that document advances in our understanding of the climate system over the Americas from proxy development, single or multi-proxy climate reconstructions, paleoclimate model simulations, proxy-system modeling, as well as paleoclimate-data assimilation. Studies addressing impacts of past climate change on ecosystems, past civilizations, and societies through changes in climate variability, intensity, or frequency of extreme events are equally encouraged. Presentations that rely on past reconstructions to put current or future climatic conditions in a longer-term context or that highlight novel educational approaches or outreach efforts are also welcome.
9. Visualizing complex ecological systems and climate change: From lenses to computer
Paleoecological datasets can provide detailed understanding of the history and complexity of ecosystem processes that often occur at decadal to millennial timescales. When coupled with statistical and dynamic modeling, such approaches potentially provide stakeholders with visualizations of past and future scenarios. This session will provide a platform of exchange for methodological development of modeling paleoecological datasets of Earth and climate systems between established and early-career researchers. It will encourage studies that combine paleoecological/paleoclimate and modeling approaches to explore past ecosystem changes, ecosystem services, climate change, and fire dynamics. The session is not limited in timescale, however, studies that deal with contemporary challenges of fire, biodiversity management, and conservation are particularly welcome. Specifically, we encourage translation of combined modeling and paleoecological work into forms that could be used to communicate research results to stakeholders and decision makers.
10. Insights into future changes in global biogeochemical cycles from studies of the past
Recent human activities have greatly altered some of the biogeochemical cycles at a planetary scale (e.g. carbon, nitrogen, phosphorus) with large impacts on climate, ecosystems and environmental processes. In this session, we welcome contributions assessing recent and past changes in biogeochemical cycles at global and regional scales, including reconstructions of their natural dynamics and process-understanding based on models within an Earth system approach.
11. Tropical and subtropical interhemispheric teleconnections during the last 2000 years: A transatlantic approach
The study of long-term climate variability in the (sub)tropics allows for a better understanding of the impacts of the different modes of oscillation, and permits scientists to delineate some potential consequences to anthropogenic global warming (AGW). Such understanding is urgent, as some of the poorest and most vulnerable communities in the world inhabit these areas. Consequently, detailed multidisciplinary studies on the consequences of previous climate change events, such as the Little Ice Age and/or the Medieval Warm Period, can provide important data that may help constrain the impacts of AGW during the next decades/centuries for these areas. Marine (sediments, corals) and continental records (sediments, speleothems, tree rings), along with existing instrumental records, provide vital information on climate variability and atmospheric teleconnections affecting this area, help scientists to discern between natural and anthropogenic modulation, and provide a basis for different attribution studies. This session is addressed to researchers who are interested in improving the understanding of the role of the ocean in modulating past natural climate variability by combining climate reconstructions based on natural archives and climate model simulations. The specific objectives are to build a synthesis of existing paleoclimate data and acquire new paleoclimate data covering the late Holocene and the past 2000 years from key sites zones in the framework of the associate projects developed in the different partners' countries. These will be combined with model results to address the associated physical processes.
12. Volcanic impacts on climate and society
Volcanic eruptions can inject large amounts of material into the atmosphere, which impacts climate and societies on regional to global scales. The PAGES VICS working group has supported research focused on reconstructing the history of past volcanism, and understanding its impacts on the climate system and societies. This session will aim to highlight some of the most novel and valuable results resulting from interdisciplinary collaborative efforts fostered by VICS over its six-year lifetime. We invite contributions focusing on reconstruction of volcanic activity from various paleoarchives and their climate effects imprinted in individual proxy records and proxy compilations, and the analyses of volcanic climate effects using modeling experiments, such as simulations associated with the sixth phase of the Climate Model Intercomparison Project (CMIP6), including both the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP) and the Paleoclimate Modeling Intercomparison Project (PMIP). We further invite interdisciplinary research which aims to analyze to which extent volcanic eruptions contributed to shaping past climate and societal changes.
13. Climate variability across scales and climate states
The Earth's climate is highly variable on all spatial and temporal scales, and this has direct consequences for society. For example, changes in variability (spatial or temporal) can impact the recurrence frequency of extreme events. Yet it is unclear if a warmer future is one with more or with less climate variability, and at which scales, as a multitude of feedbacks is involved and the instrumental record is short. We welcome contributions that improve quantification, understanding, and prediction of climate variability in the Earth system across space and timescales through case studies, idealized or realistic modeling, synthesis, and model-data comparison studies that provide insights into past, present and future climate variability on local to global, and synoptic to orbital timescales.
Members of the PAGES working group on Climate Variability Across Scales (CVAS) and others are welcome. This session aims to provide a forum to present work on:
- the characterization of climate dynamics using a variety of techniques (e.g. scaling and multifractal techniques and models, recurrence plots, or variance analyses) to study its variability including periodicities, noise levels, or intermittency
- the relationship between changes in the mean state (e.g. glacial to interglacial or preindustrial to present to future), and higher-order moments of relevant climate variables, to changes in extreme-event occurrence and the predictability of climate
- the role of ocean, atmosphere, cryosphere, and land-surface processes in fostering long-term climate variability through linear – or nonlinear – feedbacks and mechanisms
- the attribution of climate variability to internal dynamics, or the response to natural (volcanic or solar) and anthropogenic forcing
- the interaction of external forcing (e.g. orbital forcing) and internal variability such as mechanisms for synchronization and pacing of glacial cycles
- the characterization of probabilities of extremes, including rare "black swan" events and the linkage between slow (interannual to millennial) climate variability and extreme event recurrence
- the development and characterization of statistical tools and stochastic models to quantify the distribution, or scaling, of climate variability over a wide range of timescales from short, noisy, and irregular (paleo)climate timeseries, such as robust estimators for power spectral analyses, fluctuation analyses (detrended, Haar, or other) and wavelets.
14. Past extremes and risks assessment: Linking the instrumental and the paleo record
The extreme events in climate, environment, and ecosystem dynamics are in most cases relatively rare, and consequently the instrumental period has a too-short duration to provide an adequate sampling and characterization. They strongly impact the natural systems and human societies, and even the short duration events can lead to a long-term imprint on the environment. Natural, historical, and documentary archives provide records of past extreme events over a wide range of climate and environmental conditions, in particular for hydrological events (floods, droughts, storms), fires, and changes in coastal dynamics (hurricanes, tsunamis). A robust risk assessment of their probability is only possible by extending the dataseries using natural and documentary archives that record the occurrence and impact of past extreme events at any timescale. This session builds from the past experience of the PAGES Integrative Activity Extreme events and risk assessment and focuses on the occurrence and understanding of mechanisms at the origin of past extreme events. We welcome quantitative approaches in order to obtain robust probability estimates based on long-term series that can be compared directly to their equivalent derived from instrumental data. We encourage contributions dealing with modeling and data-model comparison case studies. We would also like contributions that relate past and recent extremes with risk assessment. The goals of this session are to reinforce the coordination between existing research lines and working groups, to stimulate new analysis, and to facilitate the transfer of relevant information to potential users.
15. Art and science in a changing planet: A past global perspective
Co-conveners: Graciela Gil-Romera, Alejandra Vicente de Vera and Vojtech Abraham
Art and science are the two sides of the same coin; they are two ways to understand and describe the world around us and are often narrowly interconnected. In our fast-changing planet, society demands sound science communication, as scientific concepts need to inform the general public in the most objective, evidence-based way possible. Outreach is indeed becoming even more relevant today and will continue to do so in the future as a cornerstone of our duties as academics. A paradigmatic case is that of the paleosciences, where even basic principles are sometimes difficult to communicate. While the paleosciences are essential to understanding current global change, transmitting findings and the scope of evidence from this field becomes challenging.
On a different realm of human cognition, frequently assumed to be far from science, is art. Art has the power to reconcile us with our reality, reawakening the essence of the easily forgotten value of our own lives by making even the ordinary enticing. This is even more seductive when different media are used in the artistic process, which very effectively and quickly attracts observers' attention, in addition to serving a pedagogic function. Literature, music, painting, or innovative artistic tools, such as live performances, may reach a wider audience in a more compelling way when communicating science compared to traditional scientific presentations. Besides the role of artistic creation in communicating, there is the additional input that creative process has on science itself; thus thinking about a particular subject using artistic means forces scientists to consider different aspects of the research, sometimes intensifying the observations and helping to deepen the understanding of the subject matter.
In this session, we welcome contributions from artists, scientists, and those who consider themselves both. Contributions should be intersectional, either focused on transmitting paleoscience using artistic means or those adding paleoscientific concepts to artistic products. We are therefore interested in works with a strong outreach component that use any artistic venue or means to communicate, as well as those where past global changes might be used to express artistic endeavors. We will consider all artistry domains and expertise, and will try to facilitate various means of display.
16. Towards an improved understanding of past flood variability and examples on how such data can have a bearing on present and future flood risk management
Extreme floods can have a devastating impact on societies worldwide. They cause loss of life, erode and destroy critical infrastructure, and often leave economic deprivation in their wake. Understanding present and future flood variability, and how that variability possibly links to local and global climate change, are of growing interest to the scientific community, stakeholders, and policy makers. Managing hydrological extremes is particularly relevant in the context of enabling more sustainable development. One way forward to improve our understanding of the dynamical and scientifically challenging relationship between changes in flood variability and corresponding climate conditions is to expand the length of records that detail natural variability. By extending this time series, scientists can potentially shed new light not only on how such flood patterns vary over time, but also constrain the full range of variability. There are a number of different geological and biological archives that faithfully record floods on millennial timescales, and by increasing the number of reliable reconstructions scientists can start to examine questions of reproducibility and spatial patterns, which are key to distinguishing local catchment effects versus changes in climate forcing. Despite the fact that evidence-based approaches – like the ones described here – provide rare insight into flood dynamics, this is generally not well articulated or included in adaptation planning or disaster risk-reduction strategies.
This session welcomes empirical studies based on archives such as historical data, sedimentary archives (fluvial, lacustrine- and marine sediments), tree rings, and/or speleothems to characterize flood patterns on centennial to millennial timescales, and also to show how such studies can help to improve societal preparedness against flood risk under global change scenarios. We especially welcome multidisciplinary studies where evidence-based approaches and statistical, climate, and physically based modeling are combined to assess the socio-economic and environmental impacts of extreme events. This session is not only restricted to case studies, but also welcomes contributions that explore new methodological approaches. We anticipate that this session will help to provide a better overview related to the strategies required to include information on past extreme flood events into formal Disaster Risk Reduction (DRR) assessments.
17. Dendrochronology: A flashlight into an elusive past and a tool for an uncertain future
Climate change has become one of the biggest threats to nature and humanity. Today, we are witnessing humanitarian crises due to extreme weather events such as fire, floods, heat waves and increased frequency and intensity of dry spells. Predictions of climate change are characterized by a high degree of scientific uncertainty, especially in mountain ecosystems, due to the limited availability of long-term high-quality climate data and insufficient understanding of the physical processes of interacting atmospheric circulation patterns in model simulations. Such changes are recorded in the incremental proxy environmental records that grow or accrue annually, such as tree rings, lake varves, ice cores and speleothems. Tree rings and stable isotopes in tree rings are key terrestrial archives that provide insight into past climate and environmental variability at annual resolution from local to regional scales. Tree ring proxies are also important as indicators of plant physiological responses to changing climatic conditions and disturbance regimes. These records can be used for understanding long-term hydrological and ecological processes that are needed for developing appropriate management actions and policy decisions that benefit people's livelihoods, health, and the environment.
We invite researchers to present their work related to dendrochronology and other incremental proxy records from mountain and other environments. We encourage submissions using multi-proxy measurements (ring width, stable carbon and oxygen isotopes, and wood anatomical techniques) and studies linking different proxy records (such as glaciology, lake sediments, etc.) to dendrochronological records. Applications to long-term climate reconstructions, trends, and atmospheric circulation patterns, ecology, hydrology, and ecosystem modeling at different temporal and spatial scales are particularly welcome. In this session, we will also discuss the development of tree-ring-based and other incremental proxy networks, especially regarding the need to advance dendrochronology research in Africa, where large-scale tree-ring-based data is lacking compared to other continents.
18. Using high-resolution marine archives to investigate marine climate, marine environment, and maritime societies through the Holocene
Sclerochronological marine proxy archives are used to analyze and reconstruct marine climates and marine environments at ever higher resolutions, allowing spatial and temporal leads and lags to be identified, so that the underlying mechanisms and dynamics of the marine system can be described in increasingly finer detail. The marine realm has also been a key component of the spread and transformation of human societies throughout the Holocene, and the marine climate and environment have at different times and in different places acted to make these transformations possible or inevitable and, perhaps, to make other transformations unfeasible. At the same time, human societies in maritime settings are likely to have impacted their surrounding environment. This reflects, with a marine focus, the three themes of the PAGES science structure. In this session, we will highlight the use of high-resolution sclerochronological marine archives (e.g. bivalve mollusc shells, corals, fish otoliths, coralline algae), coupled with climate and biological models, to analyze and reconstruct marine climate, the marine environment, maritime societies, and their mutual interactions, through the Holocene.
19. Understanding past hydrological changes in North Africa since the Last Glacial Maximum
About two-thirds of Africa is arid or semi-arid, and water availability is a critical factor for the well-being of ecosystems and anthropogenic activities. Studies of regional hydrologic fluctuations in North Africa since the Last Glacial Maximum reveal profound implications on ecosystems and human societies. Reconstructions of paleoenvironmental changes in such critical environments are often hindered by the lack of suitable archives under arid conditions. This session welcomes contributions from studies filling these gaps, for instance, adding climate reconstructions using marine or continental mountainous records. We thereby aim to improve the uneven distribution of data and reach a better understanding of the spatio-temporal variability of hydrologic changes over North Africa. This session is dedicated to new hydrological records from North Africa, including terrestrial and marine records, with a time span that covers all or part of the last 20 millennia. We also encourage contributions that combine proxy records with model simulations in order to explore the mechanisms and dynamics underlying the observed climate changes and address the impact that hydrological change has had on the evolution of ecosystems and human activities.
20. Societal risk arising from global change: Past, present, future
As global change accelerates, the risk of low probability, extreme cost/benefit events may be changing. At the same time, the potential for both correlated and uncorrelated events to overwhelm progress toward sustainable development goals may also be changing. We invite contributions that use observations and models of various aspects of socio-environmental systems – past, present, and future – to improve estimation of the behavior and resilience of such systems under equilibrium, non-equilibrium or different-equilibrium conditions. Contributions that span the goals of Future Earth's Risk Knowledge Action Network (Risk-KAN), the World Climate Research Program (WCRP) Grand Challenge in Weather and Climate Extremes, Integrated Risk and Disaster Research and PAGES' crosscutting integrative activities on Thresholds and Tipping Points and Extreme Events and Risk Assessment are particularly encouraged.
21. Deep histories of land-use and land-cover change in African montane regions
Co-conveners: Paul Lane and Rob Marchant
Africa's montane environments are, and were, attractive areas for human settlement due to their high diversity of resources, high productivity, supply of fuel, reliable water supply, and role as storehouses of biodiversity. African mountain landscapes result from the cumulative effects of climate and land-use change over nested timescales from years to millennia, resulting in their distinctive social-ecological systems being characterized by unique floral/faunal species and diverse and indigenous cultures, which underpin key ecosystem goods and services including resources for key crops and livestock. Africa's mountains remain directly vital to the 231 million people that live in these areas today, and are indirectly important to even more of Africa's inhabitants through the various ecosystem services they provide. However, interacting pressures from changing climates, socio-economic development, population growth, competing land uses, and national and international policies all threaten the potential future sustainability and resilience of mountain social-ecological systems (MtSES) around the world. Nowhere are these pressures, and the need to understand the interactions between communities and environment, more acute than on African mountains. The aim of this session is to draw together a series of syntheses of the major changes and continuities in land use and land cover over the last ca. 6000 years as a sample of major African montane regions along both a north-south and west-east axis, for the purposes of comparison and reflection on potential future trajectories. In this session, we welcome presentations from a range of disciplines that bring together perspectives from archaeology, paleoecology, history, anthropology, geography, and/or modeling.
22. Historical climate reconstruction and impacts utilizing written records
Written records serve unique functions in historical climate reconstruction by providing precise climate and weather information for all seasons at high resolution, as well as societal impacts, perceptions and reactions. However, use of these sources poses challenges regarding subjectivity and errors in recording and transmission, as well as discontinuities and inhomogeneities in the information they provide. Available records and possible approaches vary by country and region. This session builds on the ongoing work of the PAGES CRIAS working group to advance methods and international coordination in climate reconstruction and impacts from written records. To that end, we invite contributions making use of these sources, alone or in conjunction with natural archives and instrumental records, for high-resolution reconstruction of historical climate variability or its societal impacts. We especially encourage contributions that advance new methods in historical climatology, extend the field into less-studied regions, including North and West Africa, or advance the integration of written and paleoclimate information in historical reconstruction and impact research.
23. Climate changes and societies adaptation in northwest Africa: Paleo perspectives toward sustainable development
Africa has been the site of many major climate transitions leading to changes in both human demography and regional environmental systems. Food security, economic prosperity, and human health are some of the key development challenges that face many African societies. Northwest Africa has various natural assets to secure its development; thus, combining sustainability and development strategies is required to mitigate potential impacts on ecosystems and communities. This session will try to collate the ensemble of local studies based on instrumental, historical, and climate reconstructions to build detailed pictures of regional aspects of climate-change impacts on communities and ecosystems in the region. Specific focus will be given to contributions addressing the key communities' adaptation strategies over the last 2000 years, with a focus on the evolution of natural resources management (e.g. water, land, soil).
24. Regional synthesis of environment-climate-human interactions during the past 2000 years
Climate and environmental variability and its impact on ecosystems and human populations have been widely studied on both regional and global scales during the late Quaternary. Understanding past human-climate-environment interactions not only provides a "baseline" for comparison with the present, but is essential for unraveling the complexity of interactions and providing a basis for assessing the resilience and sustainability of the landscape system. In addition, historic human adaptations to climate change can provide guidance for modern societies to future climate fluctuations, which will help us to make better use of and better manage natural resources. This is particularly important to low-latitude regions, frequently subject to severe droughts, desertification, land degradation, socio-economic stress, and population pressure in the future.
In this session, we invite abstracts that provide insights into past environmental changes, as well as climate variability, in low-latitudes where the current vegetation and the whole biosphere are impacted by pastoralism, and where the ecosystem and the local population are highly subject to water stress. We offer a platform to share new results on climate variability, human activity, and ecosystem responses of these areas during the past 2000 years. This will help us to understand landscape/ecosystem thresholds and the complex, non-linear behavior of these systems, thus providing appropriate conservation and land management strategies. This session welcomes contributions investigating climate variability in the past, whether through modeling or high-resolution proxy records extracted from marine or terrestrial climate archives.
25. Tipping points in the Earth system: Can the past inform us about the future?
The concept of "tipping points", beyond which major, non-linear changes occur, is of obvious concern for the future of Earth systems. Paleorecords clearly document large changes on a variety of timescales, but it is less clear how to use the knowledge of these past changes, and their potential underlying causes, in future predictions. This session invites presentations about all aspects of these problems, from data studies to modeling and theoretical considerations, with a particular focus on connecting past tipping points with the future evolution of the Earth system under anthropogenic forcing.
26. Past climates in our changing mountains: Contributions from the paleoscience community
The Group on Earth Observations (GEO) Global Network for Observations and Information in Mountain Environments (GEO-GNOME) is a GEO Initiative launched in 2016 under the co-leadership of the MRI and ISAC-CNAR that aims to identify and make available transboundary and inter- and transdisciplinary environmental and social-ecological data and information on global change in mountains. This network, and data and information portal, is expected to facilitate access to key data and information to serve the needs of diverse users, from the research community for studies applicable to global assessments, such as the IPCC, to local, national, and regional managers and decision-makers working in mountains. To date, GEO-GNOME has mostly worked to identify and access data, datasets, and information gathered from observed in-situ or remote sensing Earth-observation sources in order to better understand key processes in mountains, such as elevation-dependent warming or elevation-dependent climate change, and also as a basis to perform process-oriented evaluation and validation of climate models. The GEO-GNOME focus has thus been on the recent (instrumental) past and future climate evolution in global mountains. However, knowledge of the past evolution of the Earth's climate in mountains is also crucial, where proxies that cover longer timescales hold promising potential to not only better quantify the nature and extent of dynamics at play in high-altitude regions, but also to improve our understanding of these processes and thereby put the current and projected climate conditions in mountains into perspective.
With this session, GEO-GNOME aims to explore, identify, and establish links with existing paleoclimate scientific research communities, specifically those working in mountain regions and with paleoscience databases. We encourage contributions focused on paleoclimate reconstructions in mountains from diverse sources (non-polar ice cores, mountain lake sediments, peat bogs, dendrochronology, archaeology, glacial geology, etc.) and from diverse geographical areas around the world. As a key outcome of the session, we seek to identify and establish joint collaborations to support the development and compilation of relevant data, datasets, and information on mountains from a diverse suite of paleodata sources, thereby supporting GEO-GNOME's data and information goals outlined in its 2020-2022 implementation plan.
27. Variation and responses in fire regime behavior over time and space
A series of extreme fire events like the ones in Australia, the western US, Siberia, boreal Canada, Indonesia, the Amazon, and Portugal characterized the last wildfire seasons around the globe. The increases in the length of these events, area burned, severity of the burning, impact on human health and lives lost, and economic costs suggest the emergence of novel conditions that are altering wildfire regimes. Unprecedented large fires are also affecting regions that have experienced limited burning in the last centuries to millennia, such as large-scale fires in temperate Europe and Greenland. However, long-term fire records show that fire has been and still is a critical factor shaping ecosystems on Earth, with varying degrees of frequency and intensity over time. To develop effective and sustainable fire management policies that increase resilience in a future warmer world, scientists and managers need to know more about the full range of fire variability in each ecosystem. Through studying natural fire occurrence and anthropogenic fire use across millennia, new quantitative metrics of fire occurrence in the past shed light on a range of ecosystem responses, such as trait legacy-effects and recovery rates.
In this session, we focus on identifying and measuring fire hazards and fire dynamics across timescales, and analyzing the ecological and post-fire effects on a range of ecosystems. We welcome contributions related to ecosystem dynamics and resilience, metrics of fire regimes in long-term records, and the extraction of actionable fire knowledge across space and time.
28. Regional and transregional climate variability over the last 2000 years
The Common Era of the past 2000 years is a key period for understanding the response of the climate system to various natural forcings and to evaluate the relative role of internal variability. It also provides a baseline to estimate the magnitude and regional patterns of temperature and hydroclimate changes associated with anthropogenic greenhouse gas emissions. International efforts to bring together proxy data from across the world have resulted in several large-scale data compilations for the Common Era. Similarly, there has been a notable progress in understanding and, in turn, forward modeling of, for example, hydroclimatic proxies, which facilitates comprehensive model-data comparisons. However, the relatively small signals, heterogeneous data availability and complex spatio-temporal structure of the climate changes observed during this period provide clear challenges for the methodologies, as well as opportunities, to better understand the dynamics of the climate system at decadal to centennial timescales. In this session, we welcome submissions discussing new temperature or hydroclimate records, regional to global data syntheses, data-model intercomparisons, and data assimilation experiments covering the past 2000 years.
29. Benchmarking human impacts on low-latitude aquatic systems
There are comparatively few paleolimnological records from the low latitudes. Tropical regions encompass some of the fastest growing populations, and some of the poorest communities. The increasing population is placing pressure on water resources and the ecosystem services they provide, including potable water, aquaculture, and tourism. In conjunction with this are increased pollutants as a result of human activities within wetland catchments (including land-use change, mining activities, and rudimentary waste and sanitation systems). The anthropogenic use of wetlands and their catchments has both direct (e.g. species introductions, water abstraction) and indirect (e.g. land-use changes altering hydrology) impacts. These, coupled with a lack of management of systems and climate change, are causing a cascade of impacts on aquatic ecosystem function, water quality, and ultimately ecosystem and human health.
This session will focus on the "recent" past (e.g. last 100 to 1000 years) where humans are a major agent impacting the environment and hydrology, affecting the functioning of both ecosystem services and societies. We invite submissions from researchers and practitioners working in tropical regions on past hydrological changes, human and climate impacts on aquatic systems, and the application of paleolimnology to management and socio-ecological systems.
30. Hydrology of arid regions
Co-conveners: Hind Cherkaoui Dekkaki, Abderrahim El Achheb, Bouabid El Mansouri, Fouad Amraoui, Lahoucine Hanich, Mohamed Hilali, Younes Fakir, Nour-Eddine Laftouhi, Abdenbi El Mandour, Jamal Eddine Stitou El Messari, Tarik Ghodbani, Younes Hamed, Ahmed Gaber, Souad Haida, Lahcen Benaabidate, Youssef Brouziyne, Abdelkader El Garouani and Hassan Tabyaoui
Water resources have become an important area of concern in several regions of the world, especially the arid regions, including many African countries. This session highlights new methods and analyses from recent studies that cover different ranges of hydrology and related issues via worldwide case studies such as, but not limited to, precipitation processes and observations, assessment of water budget, water resources and climate change, hydrological forecasting and prediction systems, latest advances in hydrological technology, groundwater sustainability, artificial recharge, transboundary aquifers, and sea water intrusion.
31. Quantifying relative sea-level changes from geological archives
Deciphering relative sea-level changes from geological records can provide insight into the processes that drive the response of local, regional, and global sea levels to climate forcing. To evaluate the potential impacts of future sea-level rise on global coastlines, relative sea-level records with sufficient resolution and precision are required. Additionally, the global distribution of high-resolution relative sea-level records is uneven, which hampers our ability to quantify likely future changes.
This session welcomes contributions to ongoing research efforts to quantify the timing, magnitude, and geographic variability of relative sea-level changes during the Holocene and Plio-Pleistocene. Contributions that interrogate the use of proxies and chronological methods in relative sea-level reconstructions are also welcome.
32. Marine conservation paleoecology
Co-conveners: Willem Renema and Sebastian Ferse
This session focuses on how paleobiological data can be used to understand ecosystem response to perturbation in near and deep time, and how these data can be used in conservation actions. We aim to (1) explore how conservation paleoecology can be used to understand ecosystems' responses to crises, (2) provide case studies of applications to modern ecosystems, and (3) better understand ecosystem response and recovery through environmental crises.
33. Quantifying and predicting terrestrial ecosystem responses to changing climates and land use
Increased understanding of how the terrestrial biosphere responds to climate and land-use change is needed to improve climate, vegetation, and carbon-cycle forecasts. Terrestrial paleoecological proxies, including sediment pollen, tree-rings, macrofossils, aDNA, and charcoal, provide long-term records of ecosystem dynamics. Recent advances in quantitative approaches, cyberinfrastructure, and data-model assimilation have resulted in improved quantification and understanding of past ecosystem changes and closer bridging between observations and the process-based terrestrial ecosystem models used to develop future projections. In this session, we draw on the theme of this year's OSM, "Learning from the past for a sustainable future", to highlight recent advances and establish immediate paths forward for combining paleodata directly with global vegetation models. We look forward to submissions from those using ecological proxy data together with statistical and modeling analyses to better quantify and understand macro-scale ecological responses to the Great Acceleration, characterized by high rates of vegetation and land-use change, and the emergence of novel system states. Specific topics of interest include but are not limited to (1) understanding macro-scale vegetation dynamics with networks of tree ring, paleovegetation, paleofire, or other paleoecological proxies, (2) new methods of statistical inference, and (3) data-model comparison and assimilation of paleodata into terrestrial ecosystem models.
34. Cryosphere change impacts on arctic coastal environments and ecosystems during the Holocene
Arctic climate change is causing accelerated melt of the Greenland Ice Sheet, increased runoff from Arctic glaciers, diminished sea-ice extent and volume, and degradation of permafrost, which all will profoundly impact Arctic coastal environments. A major challenge the arctic marine sciences faces is to put these changes and their impacts into a longer-term context. The ACME working group aims to refine available coastal marine proxies and to promote a leap forward in the accuracy of paleoreconstructions that are central for deciphering the interactions of the cryosphere and the Arctic coastal environments at relevant timescales. We invite contributions applying any of a range of methods and proxies to the reconstructions of past arctic coastal environments and ecosystem dynamics, as well as studies focused on processes, environmental monitoring, and proxy calibrations.
35. Past climate variability reconstructed from ice-core records: Interpretation of proxies embedded in the ice and applications to past climate reconstructions in polar regions
Ice cores are a key archive to study past climate variability. Various physicochemical proxies provide key insights into past temperature, atmospheric composition, volcanic activity, and atmospheric circulation. Despite the large body of empirical information available, we still lack a detailed, process-based understanding of the creation of the archived climatic signal. This session aims to facilitate an in-depth discussion on the extent to which climatic signals are archived in the proxy signals, how the archival processes – from the atmosphere to the surface to post-depositional changes in the firn and ice and even further smoothing/diffusion in the lower most part of the ice column – affect the recorded signal, and how to optimally recover the original signals from existing ice-core records.
We welcome contributions that shed light on this chain of processes, including interpretation of various proxies from new, or existing, ice-core records from Antarctica, Greenland, or high mountainous areas; analyses of climate-model, reanalysis, and back-trajectory data; novel application of statistical and spectral methods to proxy data; and new measurement techniques. Finally, we encourage discussion about the impact the individual processes have on the relationship between proxy and past climate variability across various temporal and spatial scales.
36. Quaternary climate change and human evolution in Africa
The impact of Pleistocene climate change on H. sapiens' evolution, cultural innovation and dispersal has long been debated. The recent discoveries of fossils of archaic and modern H. sapiens in other parts of Africa than eastern Africa (particularly in Morocco and South Africa), and outside of Africa (particularly in Israel and Greece) has intensified this discussion in recent years. Continuous, high-resolution continental and marine climate records from Africa and the surrounding regions will definitely inform this debate, which is often constrained by the lack of such records. We hope the discussions in this session will lead to a better understanding of the paleoenvironmental setting of human evolution in Africa, and the modes of human dispersal across and out of the continent. We invite contributions on these issues from a diverse range of researchers in Quaternary paleoclimate and paleoenvironmental sciences, including archaeology and paleoanthropology.
37. Peatland ecosystem functioning and ecosystem services: How paleoscience and management can feed back to each other
Peatlands are important archives of past environmental changes and, at the same time, provide vital ecosystem services including carbon sequestration and storage, water, biodiversity, fisheries, etc. In the recent past, the number of threats that pose a risk to their stability has increased globally. Climate change and other direct anthropogenic pressures may strengthen or weaken the peatland carbon sink and induce non-linear responses that may alter an ecosystem's ability to provide other ecosystem services. For example, anthropogenic pressures in tropical peatlands are proving to be more intense threats to these large tropical carbon stores than any environmental changes from climate change (Page et al. 2009, Chapter 9). In Europe, historic degradation together with climate change is threatening peatlands, and this may relate to a drying trend observed in the recent past in many European peatlands (Swindles et al. 2019). All anthropogenic burdens and rapid forcings on these ecosystems have resulted in ecological and biogeochemical changes in peatlands that are found in the stratigraphic record. For this session, we welcome scientific contributions of investigations that focus on how we may use peatland paleo records of recent or long-term changes to provide better process understanding of peatland ecosystem functioning, and to inform peatland management.
38. Ice-sheet variability and behavior through the lens of geologic data and numerical modeling
Ice sheets are major components of the climate system and play an important role in the organization of that system through their influence on sea level, atmospheric and oceanic circulation, the biosphere, and landscape evolution. Determining the evolution of the size, shape, and volume of past ice sheets provides necessary boundary conditions for deciphering how ice sheets responded to and influenced past climate changes. Evidence of past ice-sheet size and behavior are recorded in the geologic record through the presence of terrestrial deposits and geomorphic features, geochemical tracers, and lacustrine and marine sediments. Numerical models provide insight into the potential mechanisms of past and present ice-sheet change and can provide information not always available through the geologic archive alone, including ice-volume estimates, ice-flow dynamics, and transient ice-sheet reconstructions. This session seeks contributions addressing ice-sheet constraints from both geologic data and modeling studies to recreate past conditions of the global ice sheets. Topics will include, but are not limited to, remote sensing, geochronology, ice volume and sea-level contribution, and ice streams and ice dynamics.
39. Obliquity vs precession: How long exactly is a 100-ka cycle and does it even exist?
Co-conveners: Martin Kölling and Mark Maslin
The expressions "100-ka cycle" and "100-ka world" persist in geoscience to describe the length of glacial cycles after the Mid-Pleistocene Transition (MPT). This expression is based on the belief that Earth's climate has shifted from being obliquity forced with cycle lengths around 41 ka to being controlled by a lower frequency orbital forcing with a cycle length around 100 ka. This assumption has several problems: (1) Only eccentricity shows a cycle length around 100 ka, yet with minor impact on climate; (2) The last 10 glacial cycles each lasted between 76 ka and 119 ka but none of them was between 95 ka and 105 ka long; (3) The sharp 100-ka peak in frequency analysis plots of paleoceanographic data is an artifact of plotting over a frequency scale rather than over a cycle-length scale and rather spans the period from 130 to 70 ka; (4) New evidence indicates that glacial terminations seem to be directly linked to obliquity phasing, while the impact of precession is more complex. We encourage contributions that try to reconcile geological data and physical models to address the aforementioned problems.
40. Integrating method and theory for global comparisons of human demography and climate change in the Late Holocene
Understanding the causes of human population growth and its impact on ecosystems around the world poses one of the central challenges of interdisciplinary paleoscience research. The archaeological record provides the greatest time-depth for understanding how human populations build sustainable (or unsustainable) relationships with different ecosystems on Earth. However, the variability of archaeological theories, methods, and records presents challenges to globally comparative research. The PAGES Working Group Paleoclimate and the Peopling of the Earth (PEOPLE 3000) aims to build integrative theories and methods for global comparisons of human demographic change and its impact on ecosystems.
This session presents recent results from PEOPLE 3000 and seeks to include participants from around the world working to build methods and theories for integrating archaeological, paleoclimate, and paleoenvironmental records to advance research on long-term human demography and environmental sustainability.
41. Towards a global past human land-use and land-cover synthesis over the Holocene
We propose to bring together scientists working on land-use and land-cover history over the Holocene, for any area or region of the world. Land use is inferred from settlement patterns, artifact scatters, and plant and animal remains; land cover may be inferred from complimentary paleoecological data. We especially wish to consider land-use and land-cover studies that examines transient changes over multiple time periods, at large regional to continental scales. We welcome papers that take a broad-scale approach to reconstructions, as well as methodological papers that examine the challenges of translating archaeological and paleoenvironmental data into land-cover and land-use change. Papers that bring together diverse lines of evidence and those that compare outputs with those generated from land-use models are especially welcome.
This session forms part of the activities of the PAGES LandCover6k working group, an international and interdisciplinary working group dedicated to reconstructing global Holocene land use and land cover. The goal of this effort is to critically evaluate and improve models of anthropogenic land-cover change being employed by climate scientists informed by current understanding of human land-use and land-cover history.
42. Open session on past global changes
This session invites contributions from any field of past global changes. It welcomes presentations of modeling studies as well as (paleo)reconstructions.