Modelling paleoclimates and the transitions between different climatic states still represents a challenge for models of all complexities. At the same time, the past offers a unique possibility to test models that are used to predict future climate.
We invite papers on paleoclimate model simulations, including time-slices (as in the Paleoclimate Modelling Intercomparison Project) and transient simulations of climate variations on timescales ranging from millennial to glacial cycles and beyond.
Comparison of different models (complex GCMs, EMICs and/or conceptual models), between different periods, between past and future climate states, and between models and data are particularly encouraged.

The hydrological processes (floods and droughts) in the Asian region are largely controlled by the interaction between Indian Summer monsoon, East Asian monsoon, mid-latitude westerlies, along with the high mountain glaciers. Studies based on the natural archives, such as lake and marine sediments, speleothem and tree rings indicate that these components are independent of each other. However, the significant interaction between these components has a direct impact on the billions of people in the Asian continent. The impact of these components points out that the monsoon variability is in a transitional phase and heads towards a significant “tipping point.” Tipping points are critical states at which a small perturbation can alter the system either to its previous state or towards a future state. However, in the climate system, the factors controlling the tipping points are not clearly understood. The natural as well as the anthropogenic factors are the critical tipping elements that could cause the significant irreversible change in the tipping points in the natural climate systems. The paleo-data can be used to validate the climate models for the future climate prediction and delineate the role of anthropogenic versus natural climate variability in the region.
In this session we invite scientists working with palaeoclimate data, instrumental observations and climate modelling, to discuss: (i) the challenges associated with an accurate prediction of climate system on various timescales for identifying the tipping points in the Asian region; (ii) role of different teleconnections (such as El-Niño, land-sea temperature differences and north Atlantic oscillations) controlling the Asian monsoonal systems; and (iii) the anthropogenic influence on shaping the Asian climate.

The global monsoon system and its regional monsoon components have profound impacts on society and are among the most complex phenomena involving coupled atmosphere-ocean-land interactions. Monsoons can cause severe floods and droughts in the tropics and some parts of the subtropics as well as undergoing climate variability on subseasonal, interannual and decadal to centennial (or longer) time scales. In addition to its profound local effects, monsoon variability is also associated with global-scale impacts since the energy released by monsoon systems can influence the global circulation. However, it is notoriously difficult to simulate and forecast the monsoons at all temporal scales, in numerical weather prediction (NWP), subseasonal-to-seasonal and interannual-to-decadal predictions, and centennial-to-longer timescale projections. A better understanding of monsoon physics and dynamics, with more accurate simulation, prediction and projection of monsoon systems is therefore of a great practical importance to the atmospheric sciences community and society.

The combination of modern- and palaeo-monsoon research can help us to better understand the fundamental nature of the monsoon and its variability. Comparisons of monsoon responses to large-scale forcings found in the palaeoclimate record can help us to understand how the monsoon will respond to changes in forcings in the future, potentially allowing us to constrain estimates of climate change. Similarly, the wealth of observations, reanalysis products and modelling work in the contemporary period can help us piece together data from point-proxy records of the past.

This session therefore invites presentations on all aspects of monsoon research in contemporary, future and palaeoclimate periods (observational, modeling, attribution, prediction and projection) from the natural and anthropogenic variability and predictability of the monsoon systems on multiple time scales, to the impact of monsoons on extreme weather and climate events (floods, droughts, tropical cyclones, heat waves, etc.), as well as the links between monsoons and global climate change and feedbacks with the biosphere.

The seasonal reversal of monsoon winds and concurrent ocean currents, relatively deep thermocline along the equator due to the lack of steady easterlies, low-latitude connection to the neighboring Pacific and a lack of northward heat export due to the position of the Asian continent make the Indian Ocean unique among the other tropical ocean basins. These characteristics shape the Indian Ocean’s very dynamic intraseasonal, seasonal, and interannual variability, as well as its air-sea interactions. They also make the basin and its surrounding regions, which are home to a third of the global population, particularly vulnerable to anthropogenic climate change, and robust warming and trends in heat and freshwater fluxes have been observed in recent decades. Advances have recently been made in our understanding of the Indian Ocean’s circulation, interactions with adjacent ocean basins, and its role in regional and global climate. Nonetheless, significant gaps remain in understanding, observing, modeling, and predicting Indian Ocean variability and change across a range of timescales.

This session invites contributions based on observations, modelling, theory, and palaeo proxy reconstructions in the Indian Ocean that focus on understanding and predicting the links between Indian Ocean variability and monsoon systems on (intra)seasonal to interannual timescales, interactions and exchanges between the Indian Ocean and other ocean basins, decadal variability and its prediction, response to climate change, extreme events, as well as interactions between physical, biogeochemical, and ecological processes. Contributions are also sought that address research on the Indian Ocean grand challenges, as formulated by the Climate and Ocean: Variability, Predictability, and Change (CLIVAR), the Sustained Indian Ocean Biogeochemistry and Ecosystem Research (SIBER), and the International Indian Ocean Expedition 2 (IIOE-2) programs.

Mountain glaciations provide an invaluable record for past and present climate change. They are vital for any palaeoclimatologic interpretation and many related research questions. The utilization of this potential is, however, not trivial because of the wide diversity of formerly and currently glaciated mountain ranges. Apart from their specific complex and interacting geomorphological process-systems different climatic and glaciological conditions cause any subsequent global or intra-hemispheric correlations to become incredible challenging. This problem is further enhanced by ongoing specialisation within the scientific community. Working groups primarily focusing on either individual aspects of related research or selected mountain regions often remain somewhat disconnected. As a consequence of the challenges imposed on mountain glaciations, they occasionally seem to become sidelined in the context of Quaternary environmental reconstructions in comparison with other formerly glaciated regions. This discrepancy constitutes an unfortunate and unsatisfactory consequence that should be conquered.

The primary aim of this session is to evaluate the potential of mountain glaciations records and stimulate further research in this important field of research. Contributions on all relevant aspects of the topic are welcomed, for example: (a) glacial landforms and reconstruction of past glaciers, (b) dating techniques and geochronology compilations, (c) glacier dynamics and palaeoclimatic interpretations, or (d) impacts of ecosystems and human evolution/society. Submissions targeting these connections are specifically encouraged. While we encourage submitting abstracts from all abovementioned topics within the broad field of mountain glaciations, we would like to invite in particular those highlighting the specific conditions of mountain glaciations or addressing the relationship and connections between different of their aspects. To address the diversity of mountain glaciations, contributions from high-, middle-, and low-latitude mountain ranges as well as from continental to maritime regions are all welcomed. The time scale of the session will cover the whole time range from Early Pleistocene glaciations to the LGM and Holocene/modern glaciers.

During the past years, precursors of this session have steadily become more popular and attracted contributions from a wide range of research topics and study areas, both with a high diversity of methodological approaches. Their common target was to allow a better understanding of how glacial landforms should be interpreted in a (palaeo)climatic and/or chronological context. The session ultimately aims to facilitate a closer connection between different topological, methodological, and regional working groups related to various aspects of mountain glaciations in space and time. It is further designed to give everyone interested in the emerging collaborative research network “The Legacy of Mountain Glaciations” an opportunity to meet and exchange ideas and expertise.

We are pleased that Benjamin Chandler has accepted our invitation and will present a solicited talk about "Mapping the legacy of mountain glaciations".

Please note that the session conveners organized a public splinter meeting on Tuesday (April 9th) between 12.45 and 13.45 in room 0.51 (SMP 6) to meet all colleagues involved with the new application for a COST Action “Legacy of Mountain Glaciations” and those interested in the topic, We will use the opportunity to make this initiative more public and to discuss possible future directions.

Ice sheets play an active role in the climate system by amplifying, pacing, and potentially driving global climate change over a wide range of time scales. The impact of interactions between ice sheets and climate include changes in atmospheric and ocean temperatures and circulation, global biogeochemical cycles, the global hydrological cycle, vegetation, sea level, and land-surface albedo, which in turn cause additional feedbacks in the climate system. This session will present data and modelling results that examine ice sheet interactions with other components of the climate system over several time scales. Among other topics, issues to be addressed in this session include ice sheet-climate interactions from glacial-interglacial to millennial and centennial time scales, the role of ice sheets in Cenozoic global cooling and the mid-Pleistocene transition, reconstructions of past ice sheets and sea level, the current and future evolution of the ice sheets, and the role of ice sheets in abrupt climate change.

To address societal concerns over rising sea level and extreme events, understanding the contributions behind these changes is key to predict potential impacts of sea level change on coastal communities and global economy, and is recognized as one of the Grand Challenges of our time by the World Climate Research Programme (WCRP). To continue this discussion, we welcome contributions from the international sea level community that improve our knowledge of the past and present changes in sea level, extreme events, and flooding, and produce improved predictions of their future changes. We welcome studies on various drivers of sea level change and linkages between variability in sea level, heat and freshwater content, ocean dynamics, land subsidence from natural versus anthropogenic influences, and mass exchange between the land and the ocean associated with ice sheet and glacier mass loss and changes in the terrestrial water storage. Studies focusing on future sea level changes are also encouraged, as well as those discussing potential short-, medium-, and long-term impacts on coastal and deltaic environments, as well as the global oceans.

The Arctic Realm is changing rapidly and the fate of the cryosphere, including Arctic sea ice, glaciers and ice caps, is a source of concern. Whereas sea ice variations impact the radiative energy budget, thus playing a role in Arctic amplification, the Greenland Ice Sheet (GIS) retreat contributes to global sea level rise. Moreover, through various processes linking the atmosphere, ice and ocean, the change in the Arctic realm may modify the atmospheric and ocean circulation at regional to global scales, the freshwater budget of the ocean and deep-water formation as well as the marine and terrestrial ecosystems. The processes and feedbacks involved operate on all time scales and thus require several types of information: satellite and instrumental data, climate models, and reconstructions based on geological archives. In this session, we invite contributions from a range of disciplines and across time scales, including observational data, historical data, proxy data, model simulations and forecasts, for the past climate and the future. The common denominator of these studies will be their focus on a better understanding of mechanisms and feedbacks on short to long time scales that drive Arctic and Arctic-subarctic changes and their impact on climate, ocean and environmental conditions, at regional to global scales, including possible links to weather and climate outside the Arctic.

South America is home to hundreds of millions of people and harbors a wide range of unique and valuable ecosystems and resources. This makes South America, which extends from the tropics to high southern latitudes, vulnerable to a diverse range of climate change impacts. For example, future climate change scenarios suggest tropical South America is a drought hotspot due to its high sensitivity in responding to warming and drying. Thus, it is of great scientific, societal, environmental, and economic interest to better understand how climate varies and is changing over South America.

This session seeks contributions from a wide range of topics focusing on climate research over South America. Topics include, but are not limited to: climate change, climate variability, and extreme events in the past, present, and future using diagnostic, modeling, and statistical approaches.

The Arctic sea ice and high latitude atmosphere and oceans have experienced significant changes over the modern observational era. The polar climate is crucial for the Earth’s energy and water budget, and its variability and change have direct socio-economic and ecological impacts. Thus, understanding high-latitude variability and improving predictions of high latitude climate is highly important for society. Predictability studies indicate that decadal to multi-decadal variations in the oceans and sub-seasonal to multi-year sea ice variations are the largest sources of predictability in high latitudes. However, dynamical model predictions are not yet in the position to provide us with accurate predictions of the polar climate. Main reasons for this are the lack of observations in high latitudes, insufficient initialization methods and shortcomings of climate models in representing some of the important climate processes in high latitudes.
This session aims for a better understanding and better representation of the mechanisms that control high latitude climate variability and predictability in both hemispheres at sub-seasonal to multi-decadal time-scales in past, recent and future climates. Further, the session aims to discuss ongoing efforts to improve climate predictions at high latitudes at various time scales (as e.g. usage of additional observations for initialization, improved initialization methods, impact of higher resolution, improved parameterizations) and potential teleconnections of high latitude climate with lower latitude climate. We also aim to link polar climate variability and predictions to potential ecologocal and socio-economic impacts and encourage submissions on this topic.
This session offers the possibility to present results from the ongoing projects and research efforts on the topic of high-latitude climate variability and prediction, including, but not limited to Year of Polar Prediction (YOPP), and the ARCPATH-project (Arctic Climate Predictions - Pathways to Resilient, Sustainable Societies).

Multiple environmental pathways have emerged from the climatic variability and extreme weather events, which have affected the state of well-being of human health. These phenomena have affected the spatiotemporal distribution of diseases such as Zika, Dengue, Cholera, Influenza, and others through the influence of vectors on making the hosts more susceptible to diseases- ultimately leading to conditions of trigger and transmission of infections in the human population. Remote sensing and station based hydroclimatic data can be used as an early indicator to mitigate the adverse impact of these outbreaks on human health.
This session will provide a platform to discuss the impacts of enhanced climatic variability on the spatiotemporal movement of diseases and the development of early warning systems. We encourage abstract submissions on the topics of climate-linked to diseases, disease monitoring and climate-based predictions of diseases.

Recent years have seen a substantial progress in the understanding of the nonlinear and stochastic processes responsible for important dynamical aspects of the complex Earth system. The Earth system is a complex system with a multitude of spatial and temporal scales which interact nonlinearly with each other. For understanding this complex system new methods from dynamical systems, complex systems theory, complex network theory, statistics and climate and Earth sciences are needed.

In this context the session is open to contributions on all aspects of the nonlinear and stochastic dynamics of the Earth system, including the atmosphere, the ocean and the climate system. Communications based on theoretical and modeling studies, as well as on experimental investigations are welcome. Studies that span the range of model hierarchy from idealized models to complex Earth System Models (ESM), data driven models, use observational data and also theoretical studies are particularly encouraged.

Invited speaker: Cecile Penland (NOAA)

The Earth system, consisting many interacting (sub)components, has strong internal variability on many time scales, is subject to a non-stationary forcing and mostly out of equilibrium with the changes in the radiative forcing. Large-scale transitions occur, for example due to the existence of tipping points in components of the climate system, and these in many cases depend on the complex interaction between different sub-systems. Moreover, the role of small-scale processes (in many models represented as noise) to induce these transitions is not well known for many important tipping elements.

In climate science, the concept of equilibrium and transient climate sensitivity is widely used for understanding how the climate changes in response to natural and anthropogenic radiative forcing. Over the last decade considerable progress has been made in understanding and defining climate sensitivity. Nevertheless, the uncertainty in climate sensitivity remains high. Moreover, its scope is quite limited, because it deals only with long term changes of the globally averaged surface temperature and is unable to account for the existence of tipping elements and large scale transitions.

The session aims at addressing the problem of connecting fluctuations and response for the climate system, including issues like climate sensitivity, climate variability, extreme events and tipping points. In particular, general approaches and novel measures to quantify the climate response to non-stationary forcing in the climate system are encouraged.
We also aim at studying the complex interactions between the different components and subcomponents of Earth system in order to understand how these interactions influence on system/subsystems (potentially tipping) behavior. External forcing may also impact the nature of interaction between connected subsystems. The submissions which are focused on the study of reasons and mechanisms of the emergent behavior are especially welcome. Such behavior may be inferred from time-dependent connectivity in data, first principle and data-driven modelling.

We welcome contributions that investigate specific feedbacks and their impact on climate sensitivity in all components of the climate system; processes on intermediate to long time scales that are generally difficult quantify such as ocean heat uptake are particularly encouraged. In addition, we welcome contributions studying the state dependence of climate sensitivity, including those focusing on the potential proximity of tipping points.

This is a merged session of 'Climate Sensitivity, Climate Response, and Tipping Points' and 'Networked connections in geosystems: revealing, studying of mechanisms, evolution in time, influence on emergent behavior'.

Tipping elements in the Earth's climate system are continental-scale subsystems that are characterized by a threshold behavior. It has been suggested that these include biosphere components (e.g. the Amazon rainforest and coral reefs), cryosphere components (e.g. the Greenland and Antarctic ice sheets) and large-scale atmospheric and oceanic circulations (e.g. the thermohaline circulation, ENSO and Indian summer monsoon). Once operating near a threshold or tipping point, these components can transgress into a qualitatively different state by small external perturbations. The large-scale environmental consequences could impact the livelihoods of millions of people.

In this session, we aim to bring together experts presenting and discussing the state-of-the-art research on tipping elements in the Earth's climate system, both in empirical data and numerical modelling of past, present and future climate. Among other topics, issues to be addressed in this session include critical thresholds for specific tipping elements, typical time scales of tipping, interactions and feedbacks between tipping elements, the potential for tipping cascades as well as environmental and socio-economic impacts of tipping.

Large-scale atmospheric circulation dynamics are the major driver of near surface climatic and environmental variability. Synoptic climatology examines atmospheric circulation dynamics and their relationship with near surface environmental variables. Within synoptic climatological analyses, a wide variety of methods is utilized to characterize atmospheric circulation (e.g., circulation and weather type classification, regime analysis, teleconnection indices). Various linear and non-linear approaches (e.g., multiple regression, canonical correlation, neural networks) are applied to relate the circulation dynamics to diverse climatic and environmental elements (e.g., air temperature, air pollution, floods).

The session welcomes contributions from the whole field of synoptic climatology. This includes application studies for varying regions, time periods (past, present, future) and target variables and in particular contributions on the development and the comparison of methods (e.g., varying circulation type classifications) and conceptual approaches (e.g., circulation types versus circulation regimes).

Climate change in the Mediterranean region poses critical environmental issues and can affect many sectors of human activities. Contrasting climate trends, levels of exposure and vulnerability are present across this region with associated potential conflicts. Climate research is expected to contribute an increasingly precise information on the future climate and impacts of climate change in this region. A large set of instrumental records and climate proxies allows in many areas of the Mediterranean region to bridge present trends and past climate over a wide range of timescales. This session encourages contributions adopting a multidisciplinary approach and it aims to promote a dialogue between climatologists and researchers interested on the impacts of climate on human and natural systems. It aims at including contributions describing new scientific findings on the climate of the Mediterranean region, its dynamics, variability, change, and studies of climate related impacts on societies and ecosystems. The session considers different time scales (from paleoclimate to future model projections), different components (atmosphere, ocean, land and its hydrology) and factors (chemical, biological, anthropic) as well as highlights of sub-regional hotspots and climate processes.

Detecting and attributing the fingerprint of anthropogenic climate change in long-term observed climatic trends is an active area of research. Though the science is well established for temperature related variables, the study of other climate indicators including hydrometeorological variables pose greater challenges due to their greater complexity and rarity.

Complementary to this, assessing the extent to which extreme weather events and impacts are attributable to anthropogenic climate change is a rapidly developing science, with emerging schools of thought on the methodology. Once again, the attribution of hydrometeorological events, long-term trends in these events and/or their impacts is less straightforward than temperature-related events.

This session solicits the latest studies from the spectrum of detection and/or attribution approaches. By considering studies over this wide range of temporal and spatial scales we aim to identify common/new methods, current challenges, and avenues for expanding the detection and attribution community. We particularly welcome submissions that compare approaches, or address hydrometerological trends, extremes and/or impacts – all of which test the limits of the present science.

From interannual to multidecadal time scales, there is strong climate variability over both the tropical and extratropical regions of the globe. Several modes of both extratropical atmospheric circulation (NAM/AO, NPO, PNA, NAO, SAM/AAO, etc.) and sea surface temperature (AMO, PDO, North Pacific Gyre Oscillation (NPGO), North Atlantic tripole (NAT), etc.) have been proposed to explain the extratropical climate variability. These modes have profound impacts on the global and regional climates (i.e., temperature, precipitation, frequency of high-impact weather/climate events such as hurricane/typhoon, drought/flood and cold/heat waves, etc.). The associated dynamics and physical processes, such as the ocean-atmosphere interaction, coupled oceanic-atmospheric bridge, atmospheric internal dynamics and oceanic dynamics, are important for understanding the tropical-extratropical climate variability and thus have implications for the interannual to decadal predictability. However, the relevant dynamics and processes are not very well represented in current climate system models. Often this is due to a lack of observations of the processes being modelled. Contributions are welcome from, but not limited to, research on observational, theoretical and modeling studies on the following topics:
1. Physical processes and dynamics in the atmosphere/ocean and atmosphere-ocean coupling associated with the tropical-extratropical climate variability on time scales from years to multi-decades.
2. The impacts and teleconnections of the tropical-extratropical climate variability on a broad range of time scales and underlying physical mechanisms.
3. Comparison of observed and simulated tropical-extratropical climate variability and its climate impacts.
4. Predictability, prediction and projection of tropical-extratropical atmospheric and oceanic variability at various time scales.

The large-scale atmospheric circulation strongly influences Earth's climate, both locally and globally, via its transport of energy, moisture, and momentum. While our ability to simulate the global circulation is improving, large model biases and uncertainties in climate change projections persist. Our theoretical understanding of how atmospheric circulations respond to climate changes is also limited, particularly on regional scales and in the presence of zonal asymmetries. Advancing our knowledge of the underlying dynamics is therefore crucial for reliable climate projections and for correctly interpreting palaeoclimate records.

The objective of this session is to advance our mechanistic understanding of atmospheric circulation changes and to analyse their impacts at global and regional scales, specifically on precipitation in past, present, and future climates. We encourage theoretical, observational and modelling contributions on tropical (ITCZ, monsoons, Hadley & Walker circulations, MJO) and extratropical circulations (jet streams, storm tracks, blocking).

Agriculture is an important sector of any economy of the world. Agriculture productions are highly dependent on the climate change and variability. Changes in hydro-meteorological variables can influence crop yield and productivity at many places. Further, climate change can influence nutrient levels, soil moisture, water availability and other terrestrial parameters related to the agricultural productivity. Changes in the frequency and severity of droughts and floods could pose challenges for farmers and ranchers and threaten food safety. Further, changes in climate can influence meteorological conditions and thus can influence the crop growth pattern. It may also influence irrigation scheduling and water demand of the crops. The effects of climate change also need to be considered along with other evolving factors that affect agricultural production, such as changes in farming practices and technology.

The purpose of the proposed session is to gather scientific researchers related to this topic aiming to highlight ongoing researches and new applications in the field of climate change and agriculture. In this framework, original works concerned with the development or exploitation of advanced techniques for understanding the impact of climate change on agriculture will be invited.

The conveners of this session will encourage both applied and theoretical research in this area.

This session is the result of a merger of two sessions:
Session CL4.28/AS3.6/GM10.2/SSP3.25
"Aeolian dust: initiator, player, and recorder of environmental change", and
Session AS3.7
"Atmospheric Desert Dust characterisation through Remote Sensing observations".

Together, these two sessions cover a huge range of scientific disciplines that study mineral-dust generation, transport, and deposition, as well as the many roles that mineral dust plays in environmental change.

The merger has resulted in a very nice set of interesting dusty abstracts covering huge ranges of spatial and temporal scales and with contributions from many scientific disciplines including atmospheric science, remote sensing, (palaeo)climate science, geomorphology and sedimentology but also human health and environmental science. We look forward to an inspiring and challenging PICO session and we invite you to participate!

Public information:
We have three PICO blocks and two invited speakers (in between the 2-minute madness and PICOs):
1) Vassilis Amiridis (10.45 - 11.00) - Dust remote sensing advances in the framework of ACTRIS
2) Carlos Pérez García-Pando (14.00 - 14.15) - FRontiers in dust minerAloGical coMposition and its Effects upoN climaTe (FRAGMENT)

The interaction of processes between the land surface, the planetary boundary layer (PBL), and the free troposphere are crucial for the understanding of weather and climate including extremes such as heavy precipitation and droughts. This requires an advanced understanding and modeling of the exchange of momentum, water, energy, and carbon at interfaces. In this session, we present and discuss current research activities contributing to this understanding, including L-A interaction and feedback to the diurnal cycle of the PBL, clouds, and precipitation as well as surface fluxes such as evapotranspiration and entrainment. We accept observational and modeling approaches to address these challenges. With respect to the observations, emphasis is put on the application of new sensor synergies, e.g., using active remote sensing for studying land surface exchange processes and entrainment at the PBL top, which have been addressed in field campaigns. With respect to theoretical understanding and modeling, we are focusing on new insights by feedback diagrams and grey zone experiments down to the large eddy simulation scale.

Changes in seasonal timing affect species and ecosystem response to environmental change. Observations of plant and animal phenology as well as remote sensing and modeling studies document complex interactions and raise many open questions.

We invite contributions with cross-disciplinary perspectives that address seasonality changes based on recent plant and animal phenological observations, pollen monitoring, historical documentary sources, or seasonality measurements using climate data, remote sensing, flux measurements or modeling studies. Contributions across all spatial and temporal scales are welcome that compare and integrate seasonality changes, study effects of long-term climate change or single extreme events, emphasize applications and phenology informed decision-making, discuss species interactions and decoupling, advance our understanding of how seasonality change affects carbon budgets and atmosphere/biosphere feedbacks, and integrate phenology into Earth System Models.

We emphasize phenology informed applications for decision-making and environmental assessment, public health, agriculture and forest management, mechanistic understanding of the phenological processes, and effects of changing phenology on biomass production and carbon budgets. We also welcome contributions addressing international collaboration and program-building initiatives including citizen science networks and data analyses.

Mountains cover approximately one quarter of the total land surface on the planet, and a significant fraction of the world’s population lives in their vicinity. Orography critically affects weather and climate processes at all scales and, in connection with factors such as land-cover heterogeneity, is responsible for high spatial variability in mountain weather and climate.

Due to this high complexity, monitoring and modeling the atmosphere and the other components of the climate system in mountain regions is challenging both at short (meteorological) and long (climatological) time-scales. This session is devoted to the better understanding of weather and climate processes in mountain and high-elevation areas around the globe, as well as their modification induced by global environmental change.

We welcome contributions describing the influence of mountains on the atmosphere on meteorological time-scales, including terrain-induced airflow, orographic precipitation, land-atmosphere exchange over mountains, forecasting and predictability of mountain weather. Furthermore we invite studies that investigate climate processes and climate change in mountain areas and its impacts on dependent systems, based on monitoring and modeling activities. Particularly welcome are contributions that merge various sources of information and reach across disciplinary borders (atmospheric, hydrological, cryospheric, ecological and social sciences).

A planned outcome of this session is a summary document providing a mountains perspective and input for the IPCC Sixth Assessment Report, more specifically for Working Group I report on the Physical Sciences Basis and the cross-chapter paper on 'Mountains', which is flagged for the Working Group II report. This summary document is organized and supported by the Mountain Research Initiative (MRI).

The Arctic realm hosts vast extended continental shelves bordering old land masses, one of the largest submarine Large Igneous Provinces (LIPs) -the Alpha-Mendeleev Ridge - of Mesozoic age, and the slowest mid-ocean spreading ridge (the Gakkel Ridge) on the globe. Extreme variations in the evolution of landscapes and geology reflect the tug-of-war between the formation of new oceans, like the North Atlantic, and the destruction of older oceans: the South Anyui, Angayucham and North Pacific, which were accompanied by rifting, collision, uplift and subsidence. The causal relationships between the deep-mantle and surface processes in the Circum-Arcic region remain unclear. Geoscientific information on the relationship between the onshore geology and offshore ridges and basins in combination with variations in the mantle is the key for any deeper understanding of the entire Arctic Ocean.
This session provides a forum for discussions of a variety of problems linked to the Circum-Arctic geodynamics and aims to bring together a diversity of sub-disciplines including plate tectonics, mantle tomography, seismology, geodynamic modelling, igneous and structural geology, geophysical imaging, sedimentology, geochemistry. Particularly encouraged are papers that address lithospheric-mantle interactions in the North Atlantic, the Arctic and North Pacific regions, mantle dynamics and vertical and horizontal motion of crustal blocks and consequences for paleogeography. As geologic and tectonic models are inherently tied with changes in the oceanographic and climatic development of the Arctic, we also invite studies that focus on the interplay between these processes and across timescales. Lastly, we would like to invite contributions from studies concerning the implications of how the Arctic’s geography and geology are portrayed by modern data and issues related to jurisdiction and sovereign rights with particular focus on the UN Convention on the Law of the Sea.

Public information:
This session provides a forum for discussions of a variety of problems linked to the Circum-Arctic geodynamics and aims to bring together a diversity of sub-disciplines including plate tectonics, mantle tomography, seismology, geodynamic modelling, igneous and structural geology, geophysical imaging, sedimentology, geochemistry. As geologic and tectonic models are inherently tied with changes in the oceanographic and climatic development of the Arctic, we also show results from studies that focus on the interplay between these processes. The implications of how the Arctic’s geography and geology are portrayed by modern data and issues related to jurisdiction and sovereign rights with particular focus on the UN Convention on the Law of the Sea are also discussed.

Present-day glacial and periglacial processes in cold regions, i.e. arctic and alpine environments, provide modern analogues to processes and climatic changes that took place during the Pleistocene, including gradual retreat or collapse of ice sheets and mountain glaciers, and melting and shrinking of low-land permafrost. Current changes in mid-latitude mountain ranges could also serve as a proxy for future changes in arctic regions within a context of climate change (e.g. speed-up of creeping permafrost features, relictification of rock glaciers).

We invite contributions that either:
1. investigate present-day glacial and/or periglacial landforms, sediments and processes to describe the current state, to reconstruct past environmental conditions and to predict future scenarios in cold regions; or
2. have a Quaternary focus and aim at enhancing our understanding of past glacial, periglacial and paraglacial processes, also through the application of dating techniques.

Case studies that use a multi-disciplinary approach (e.g. field, laboratory and modelling techniques) and/or that highlight the interaction between the glacial, periglacial and paraglacial cryospheric components in cold regions are particularly welcome.

Keynote lecture:
Hanne Hvidtfeldt Christiansen (Svalbard): Permafrost thermal dynamics in periglacial landforms in Svalbard during the last decade
Martin Margold (Prague): The retreat chronology of the western Laurentide Ice Sheet

Water and energy are essential to human society, and their supplies are vulnerable to climate change. For example, climate change will have impacts on the quantity and quality water resources, which may affect water availability for cooling at power plants, and on the yield of clean energy such as hydropower, wind power and solar energies. Considering increasing intensity and frequency of climate extremes in a warming world, understanding and quantifying the interdependence and challenges among climate, water and the energy system is critical. Considerable research is being conducted on some aspects of the climate-water-energy nexus, but this nexus is regionally diverse and has many unexplored facets. We aim to bring together researches focusing on the climate-water-energy nexus to both share current research and identify knowledge gaps.
To assess the integrative impacts of climate and climate change on water and energy systems and advance our understanding of the climate-water-energy nexus, we welcome contributions that focus on water and energy issues under a warming climate, including, but not limited to:
• climate modelling and future climate simulation with a focus on water availability
• Regional analyses of precipitation and water availability
• impacts of climate change on water resources
• impacts of climate change on clean energy yield, operation and management
• impacts of climate extremes on traditional energy production and delivery

Water is the defining feature of the habitable Earth; it is essential for all life as we know it. Evolution and maintenance of life in extremely water limited environments, which cover significant portions of the Earth, is not well understood. Akin to life, water-driven processes leave unique marks on the Earth’s surface. Mars is the only other planet currently known to bear the marks of water-driven surface processes, albeit fossil and of great age. The slow biotic and abiotic surface processes that may operate even in the virtual absence of liquid water are still essentially unknown. What is evident is that transient episodes of increased water availability can leave long lasting traces in extremely water limited environments. Intriguingly, those traces of bursts in Earth surface evolution have rarely been related to bursts in biological colonization/evolution, and vice versa, although both relate to the same trigger: water.

The objective of this session is to showcase research on the mutual evolutionary relationships between Earth surface processes and biota in arid to hyper-arid systems, where both biota and Earth surface process are severely and predominantly limited by the availability of water (rather than by extreme temperatures).
Solicited topics include (not exhaustive):
• fingerprints of biological activity at the (water) limit of the habitable Earth
• surface processes operating in the (virtual) absence of liquid water on Earth or extraterrestrial analogues (e.g. Mars)
• thresholds for biological colonization and concurrent fluvial transformation of landscapes
• tipping point(s) of biotically and abiotically controlled Earth surface systems
• chronometric and spatial information on the colonization and radiation of biota
terrestrial climatic records of (hyper-) arid regions on Earth

Marine geological processes cover a range of different disciplinary fields and their understanding usually requires an interdisciplinary approach. The interaction of geological, physical oceanographic, chemical and biological mechanisms in marine geological processes ranging from sediment erosion and deposition, to hydrothermal and fluid flow systems, to early diagenesis and geomicrobiology, is of specific interest. Such processes may take place in shallow or deep, in tropical and glacial environments, and they may be natural or partly human-influenced. Climate-induced perturbations in marine geological processes have occurred in present and past, and potentially will also occur in the future. Several of these processes may also have a profound human impact, such as tsunamis generated by tectonic or mass-slumping events, coastal erosion in response to changed currents or river discharge, and sediment gravity flow in deep waters affecting human infrastructures. /We encourage comprehensive and interdisciplinary abstracts within the broad field of marine geology and with direct relevance to marine processes or deposits concerned with rocks, sediments, and geo-physical and geo-(bio)chemical processes that affect them.

Ongoing climate change and a shorter return period of climate and hydrological extremes has been observed to affect the distribution and vitality of ecosystems. In many regions, available water is a crucial point of survival. Risk can be enhanced by the exposure and/or by the vulnerability of the affected ecosystem.
The session focuses on the complex assessment of all determining factors through a joint utilization of a broad spectrum of databases and methods (e.g. field and laboratory measurements, remote sensing, modelling and monitoring techniques) that can provide a suitable basis for developing long-term strategies for adaptation.
The session should provide a multidisciplinary platform for sharing experiences and discussing results of local and catchment scale case studies from a wider range of relevant fields such as
• observed impacts and damage chains in natural ecosystems induced by climate and hydrological extremes;
• correlation between the underlying environmental factors (e.g. climate, water holding capacity, soil characteristics) and the distribution/vitality of ecosystems;
• integrated application or comparison of databases and methods for the identification and complex assessment of ecosystem responses to abiotic stress factors;
• expected tendencies of abiotic risk factors affecting and limiting the survival of the vulnerable species.
Contributions are encouraged from international experiences, ongoing research activities as well as national, regional and local initiatives.

Hydroclimatic conditions and the availability of water resources in space and time constitute important factors for maintaining an adequate food supply, the quality of the environment, and the welfare of inhabitants, in the context of sustainable growth and economic development. This session is designed to explore the impacts of hydroclimatic variability, climate change, and the temporal and spatial availability of water resources on: food production, population health, the quality of the environment, and the welfare of local ecosystems. We particularly welcome submissions on the following topics:

Complex inter-linkages between hydroclimatic conditions, food production, and population health, including: extreme weather events, surface and subsurface water resources, surface temperatures, and their impacts on food security, livelihoods, and water- and food-borne illnesses in urban and rural environments.

Quantitative assessment of surface-water and groundwater resources, and their contribution to agricultural system and ecosystem statuses.

Spatiotemporal modeling of the availability of water resources, flooding, droughts, and climate change, in the context of water quality and usage for food production, agricultural irrigation, and health impacts over a wide range of spatiotemporal scales

Intelligent infrastructure for water usage, irrigation, environmental and ecological health monitoring, such as development of advanced sensors, remote sensing, data collection, and associated modeling approaches.

Modelling tools for organizing integrated solutions for water, precision agriculture, ecosystem health monitoring, and characterization of environmental conditions.

Water re-allocation and treatment for agricultural, environmental, and health related purposes.

Impact assessment of water-related natural disasters, and anthropogenic forcings (e.g. inappropriate agricultural practices, and land usage) on the natural environment; e.g. health impacts from water and air, fragmentation of habitats, etc.

The nature of science has changed: it has become more interconnected, collaborative, multidisciplinary, and data intensive. Accordingly, the main aim of this session is to create a common space for interdisciplinary scientific discussion, where EGU-GA delegates involved in geoscientific networks can share ideas and present the research activities carried out in their networks. The session represents an invaluable opportunity for different networks and their members to identify possible synergies and establish new collaborations, find novel links between disciplines, and design innovative research approaches.

Part of the session will be focused on COST (European Cooperation in Science and Technology) Actions*. The first edition of the session (successfully held in 2018) was actually entirely dedicated to the COST networking programme and hosted scientific contributions stemming from 25 Actions, covering different areas of the geosciences (sky, earth and subsurface monitoring, terrestrial life and ecosystems, earth's changing climate and natural hazards, sustainable management of resources and urban development, environmental contaminants, and big data management). Inspiring and fruitful discussions took place; the session was very well attended. We are looking forward to continuing the dialogue this year and to receiving new contributions from COST Action Members.

Another part of the session will be dedicated to the activities of other national and international scientific networks, associations, as well teams of scientists who are carrying out collaborative research projects.

Finally, the session is of course open to everyone! Accordingly, abstracts authored by scientists not involved in wide scientific networks are most welcome, too! In fact, in 2018 we received a good number of such abstracts, submitted by individual scientists or small research teams who wished to disseminate the results of their studies in front of the multidisciplinary audience that characterizes this session, as an alternative to making a presentation in a thematic session. This may be a productive way to broaden the perspective and find new partners for future interdisciplinary research ventures. We hope to receive this kind of abstracts this year, as well.


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* COST (www.cost.eu) is a EU-funded programme that enables researchers to set up their interdisciplinary research networks (the “Actions”), in Europe and beyond. COST provides funds for organising conferences, workshops, meetings, training schools, short scientific exchanges and other networking activities in a wide range of scientific topics. Academia, industry, public- and private-sector laboratories work together in Actions, sharing knowledge, leveraging diversity, and pulling resources. Every Action has a main objective, defined goals and clear deliverables. This session was started as a follow up initiative of COST Action TU1208 “Civil engineering applications of Ground Penetrating Radar” (2013-2017, www.GPRadar.eu).