Monsoons in Space and Time: Patterns, Mechanisms and Impacts
Conveners: Rengaswamy Ramesh, Rajeev Saraswat, Ralph Schneider, Pinxian Wang
Monsoon is the life-line of several low-latitude regions. Any change in monsoon precipitation severely affects the food production for the population-rich societies. In order to be able to predict imminent monsoon changes, it is important to understand the dynamics of the monsoon system at regional and global scales. Studies of past monsoon variability over long time periods from different proxy records as well as synoptic results from sensitivity experiments with Earth system models, will help to understand monsoon dynamics.
Such records and model results are also required to distinguish between natural and anthropogenic contributions in monsoon variability. Therefore, the proposed session will include contributions that discuss past monsoon changes from both the terrestrial and marine archives as well as from paleoclimate modelling
Regional Climate Variability Over the Last 2000 Years
Conveners: Joelle Gergis, Guillaume Leduc, Jürg Luterbacher, Steven Phipps
Several initiatives have focused recently on the climate of the past millennia, including the syntheses performed within the framework of the PAGES 2K network and the new model simulations performed according to the CMIP5/PMIP3 protocol. This session will be an opportunity to bring together the different groups involved to discuss the spatio-temporal structure of climate variability over the past 2000 years, the agreement between the models and the data, and the causes of the observed changes.
Key points to address will be the long-term changes over the whole period, the validity of the classical view of a transition between a Medieval Warm Period and a Little Ice Age in various regions, analysis of multi-annual climatic anomalies and the assessment of recent decades from a longer-term perspective.
New Approaches to Data Assimilation and Data-Model Comparison
Conveners: Basil Davis, Daniel Ariztegui, Simon Brewer, Hugues Goosse
The past provides a proving ground for models outside of our modern experience, and against which predictions can be made and evaluated using the palaeoenvironmental record. On the other hand, models can also help us to understand the signal recorded in proxies. Finally, by combining information provided by models and proxy records through data assimilation, new insights into the dynamics of the system can be obtained.
This session is focused on how data and models can be used jointly to test our understanding of the Earth system and thereby reduce the uncertainties attached to predicting future environmental change. Model data-comparisons and data assimilation experiments using models of climate, ocean, cryosphere, land-surface and other palaeoenvironmental processes at the global to regional scale over any time-scale in the past are welcome.
Climate Modes in the Past
Conveners: Ed Hathorne, Nerilie Abram, Manish Tiwari, Thomas Felis
Important climate modes such as the El Niño-Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), the Indian Ocean Dipole (IOD), the Pacific Decadal Oscillation (PDO), the Southern Hemisphere Annual Mode (SAM), and the monsoon systems are characterised by seasonal, inter-annual, decadal and centennial variability. Improving our understanding of these natural modes of variability is essential as they modulate droughts and floods on time scales relevant to society.
Reconstructing this high frequency variability is a challenge that can be addressed with analyses of annually banded archives such as coral skeletons, trees or bivalves as well as with ice cores, speleothems and various components of high accumulation rate or varved sediments. Other studies are applying geochemical analyses of many individual foraminifera shells to investigate seasonal and inter-annual variability in the past ocean. This session welcomes contributions investigating seasonal to centennial climate modes in the past, whether through modeling or high resolution proxy records extracted from marine or terrestrial climate archives. In particular, we encourage contributions combining different archives and climate model simulations.
Abrupt Changes and Extreme events - Assessment and Risks
Conveners: Ray Bradley, Pierre Francus, Manfred Mudelsee
Abrupt changes and extreme events are recorded in many natural archives of climate. This session welcomes contributions illustrating how the intensity and the speed of abrupt changes, and the frequency and magnitude of extreme events can be recognised, dated and quantified in order to provide an assessment of their frequency and relationship to forcing factors.
Contributions using annually resolved archives are particularly relevant when their analysis yields rates of change and recurrence estimates. We also welcome contributions about statistical approaches used to define the concept of "abrupt changes" and "extreme events" in a useful way for society and stake holders.
Past Changes in Fluvial Systems, Floodplains and Estuaries
Conveners: Thomas Hoffmann, Onkar S. Chauhan, Peter Gell, Rajiv Sinha
Fluvial systems are the major dispersal agents of water, sediment and nutrients from the continents to the ocean and have sustained civilizations for more than 5000 years. Unraveling past changes of fluvial and lacustrine processes in response to tectonics, climate, and land use change is a key area of research in fluvial geomorphology and paleolimnology.
Major themes of this session include:
- Methodologies to investigate floodplain response to environmental change at different spatial and temporal scales using alluvial, limnic and estuarine records.
- Reconstruction of fluvial dynamics and its impact on coastal systems in response to external perturbations.
- Cause-effect relationship between environmental change and floodplain development, scale-dependency of fluvial processes and their importance for buffered and delayed fluvial and lacustrine response.
- Connectivity structure of channel networks and sediment fluxes – implications for biogeochemical (e.g. C, N, and P) cycles and sediment infilling.
- Interactions of river morphology, hydrology and ecology and their implications for river and wetland restoration, and ecosystem services.
Sensitivity of the Cryosphere: Past and Future
Conveners: Olga Solomina, Anders Carlson
All components of the cryosphere - snow, river, lake and sea ice, glaciers, ice sheets, frozen grounds - are extremely sensitive to climate changes. This session focuses on the sensitivity of the cryosphere on a wide range of time scales from annual to orbital and tectonic. We will consider the variations and trends in the cryosphere components in the past in relation to climate change with the focus on quantitative estimates of mass balance, area and volume changes of glaciers and ice sheets, and climatic impacts on the hydrologic system, sea ice and permafrost.
Areas of special interest are glacier and ice-sheet records and their climate forcings and contributions to sea-level variability, along with sea-ice records during “warm” periods in the Cenozoic (e.g., “Medieval Warm Period”, early Holocene, isotope stages 5e, 11, the Pliocene and Miocene). The progress in the modeling and projections of Earth’s paleo and future cryospheric components will also be discussed.
Natural and Anthropogenic Transformation of Land Cover During the Holocene
Conveners: Carsten Lemmen, Marie-José Gaillard, Jed Kaplan, Anupama Krishnamurthy
A long-term and supraregional reconstruction of the state of the planet and societies over the Holocene must take into account the dynamic transformations of the Earth's surface by natural and anthropogenic processes. In terms of past land-cover changes, the local to regional spatial scales of palaeoecological and -climatological reconstructions and archaeological/historical evidence meet the spatial scale of global palaeo-Earth System and human ecology models; in terms of past land-cover changes, reconstructions are confronted with deductive approaches from palaeodemography and -economy.
This session aims to achieve a dialogue between the research communities: those systematically collecting and interpreting proxy data that can be used to inform and improve models of past land-cover change; and those developing and exploring spatially and temporally explicit models of human activities needed for hypotheses testing on the dynamic interactions between people and land cover. Together, we want to disentangle natural from anthropogenic causes behind land-cover changes and its impacts. We also wish to discuss the Anthropocene issue, whether the concept is useful and, if so, how to define its lower boundary. Studies using a multidisciplinary approach and/or stimulating discussion on integration of social and natural sciences are particularly relevant, as well as as studies on - but not necessarily limited to - tropical and monsoon-affected regions.
This session contributes to the PAGES Focus 4 'Past Human-Climate-Ecosystem Interactions' programme and, in particular, the working groups on Regional Integration, Human Impact on Terrestrial Ecosystems (HITE), and Land Use and Land Cover.
Climate Impact on Human Evolution and Civilizations
Conveners: Mark Maslin, Dhananjay A. Sant, Martin Ziegler
Within this session we would like to discuss the response of hominins and modern humans to past continental climatic changes on orbital to decadal timescales from the Pliocene to the Anthropocene. This includes a broad perspective on the evolution of early hominins, the role of climate in the origin of our species, human cultural roots and their dispersal patterns, impact of climate on the rise and fall of civilizations and the origins of human impacts on the planet.
Sea Level Change and the Coastal Zone: Threats for Human Societies
Conveners: Anne de Vernal, Yusuke Yokoyama, Benjamin P. Horton, Adam D. Switzer
A large part of the world’s population lives in coastal areas where marine resources are readily available. However, coastal and near shore zones are particularly vulnerable to global changes, not only because of the on-going “eustatic” sea level rise, and of long-term subsidence that is enhanced near major river estuaries and deltas, but also because of variations in storminess and extreme climatic events such as cyclones in low-middle latitudes, in addition to pernicious effect of permafrost thawing in polar and subpolar regions, adding to geological hazards in general (e.g., earthquakes and tsunamis).
Beyond the effect of climate changes, the anthropogenic stress may alter coastal environments through eutrophication, ocean acidification, hypoxia, red tides, etc. In such a context, the reconstruction of natural trends and the understanding of short to long term processes in the coastal zones are critical for an assessment of their fate and a better planning of their management. We invite papers focusing on sea level change and other processes that may affect coastal and nearshore environments from low to high latitudes.
Biodiversity and Refugia - Lessons Learned from the Past
Conveners: Sheri Fritz, Surangi Punyasena, Kathy Willis
The geological record provides insight into the long-term dynamics of populations and communities and the processes that generate biodiversity, including the role of cold and warm-stage refugia, where organisms persisted through unfavorable environmental conditions in adjoining areas.
This session welcomes contributions that use fossils, molecular and geochemical tools, and/or modeling to examine how climate change, biological interactions, or other environmental conditions affected the past and present composition and distribution of organisms and influenced patterns of biodiversity. We invite contributions from high to low latitudes and that consider any time interval within the Cenozoic.
Climate change: Physical forcings and biogeochemical feedbacks
Conveners: Jennifer Marlon, James Levine, Jérôme Chappellaz, Bärbel Hönisch
Our understanding of past and future climate- and biogeochemical changes rests on modern observations, paleo-proxies and models. Modern and paleo data, however, are limited and uncertain, as is our understanding of the science manifested in the models. As a result, reproducing past climate changes and the underlying feedbacks between the atmosphere, ocean, biosphere and lithosphere remains a great challenge.
This session seeks new and evolving insights into the history and strength of key forcings on the Earth energy balance (greenhouse gases, solar irradiance, aerosols and volcanic activity, surface albedo notably associated with land use, vegetation and cryospheric changes) and biogeochemical feedbacks (based on observations and modelling) in relation to: greenhouse gases, the carbon cycle, dust, fire and ocean acidification.
Past Warm Periods Informing the Anthropocene
Conveners: Stijn De Schepper, Bjørg Risebrobakken, Bette Otto-Bliesner, Stéphanie Desprat
Global climate predictions indicate that by the end of this century global temperature will have risen to levels unprecedented during instrumental times. Studies of past warm periods throughout Earth's history are key to understand Earth system dynamics and the natural variability of the climate system in a globally warmer world. For this session, we solicit data and model contributions investigating ocean, land, atmosphere and cryosphere interactions during past warm climates. We welcome contributions from each past warm period that can provide insights into the present and future state of Earth's climate.
Natural and Human Effects on Ecosystem Processes
Conveners: Janet Wilmshurst, Amalava Bhattacharyya, Mukund Kajale
Increasingly, detailed palaeoecological reconstructions are being used to help understand current ecological processes and to address global conservation issues. Palaeoecological studies are starting to move beyond merely presenting trajectories of species composition over time, towards more detailed analyses of species dynamics and responses to both natural and human induced forces.
We invite presentations on palaeoecological studies that evaluate ecosystem responses to lost or altered ecological interactions; species extinctions and introductions; extinction lags; disrupted mutualisms; nutrient cycling and changing herbivory regimes. We encourage studies based on any type of archive (e.g., sediments, coprolites, nests, cave deposits, tree rings etc).
The Role of Ocean Circulation in Climate Dynamics
Conveners: Frank Lamy, Jörg Lippold, A. D. Singh, Devesh K Sinha
Ocean circulation changes including atmosphere-ocean interactions and teleconnections between high and low latitudes play an important role for understanding processes and feedbacks of past and future climate change. Important surface and deep ocean circulation changes occurred at tectonic timescales, related to the opening and closure of major ocean gateways, and at orbital timescales where the ocean substantially contributes to the forcing of glacial-interglacial climate cycles.
Furthermore, millennial to decadal-scale circulation in the global thermohaline circulation and more regional oceanographic features are supposed to be responsible for rapid climate changes particularly relevant for human societies. We invite proxy-data and model-based contributions on all aspects of large and regional-scale ocean circulation and related atmospheric dynamics.
Open Session on Latest Highlights in Paleoscience
Hubertus Fischer, Denis-Didier Rousseau, Liping Zhou
The focus of the PAGES OSM "A compass of future Earth" is the intersection of paleoscience and sustainability research. However, many outstanding results in paleoscience are created constantly that redefine our understanding of the Earth system, but may not be directly targeted to resolve the pressing problems we face in the Anthropocene. It may be this basic, new knowledge that may open unforeseen avenues for the future.
The "Open Session on latest highlights in paleoscience" is the stage for you to present such outstanding results and propose new avenues of paleoresearch, methods or topics to a broad interdisciplinary audience. Accordingly, the open session invites contributions from latest paleo reconstructions and modeling studies but explicitly invites also contributions that present new quantitative proxy developments, high-impact process studies, new methods in paleoclimate and biogeophysical science or latest developments in chronology.