University of Adelaide, Australia
Linda’s research revolves around improving our understanding of modern and ancient phytoplankton and their relationships with the environment - now, in the past and in the future. Linda maintains a broad, interdisciplinary background in marine science, biological oceanography, micropaleontology and marine palaeo-genomics. She is particularly passionate about ship work at high latitudes and exploring marine sediment records to investigate phytoplankton-environment relationships over geological timescales. As a postdoc at the Australian Centre for Ancient DNA, University of Adelaide, Linda is currently investigating the timing and dynamics of harmful algal blooms using East Australian coastal sediment records spanning the last ~12,000 years.
Oregon State University, USA
Ed Brook is a Distingushed Professor in the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University. His primary work uses polar ice cores as recorders of past climate change, focusing on the relationship between greenhouse gases and climate on time scales of decades to hundreds of thousands of years, but he occasionally delves in to other areas of geochemistry. He received a BS in Geology from Duke University, MS from University of Montana, and PhD from the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution. He was subsequently a NOAA Climate and Global Change Post Doctoral Fellow, working with Michael Bender at the University of Rhode Island. Ed is a recipient of the Aldo Leopold Leadership Fellowship, and a fellow of both the American Geophysical Union and the American Association for the Advancement of Science. He is also active in service to the scientific community, including co-chairing IPICS, participating in numerous advisory groups in the US polar science community, and serving on the PAGES Steering Committee.
Niels Bohr Institute, University of Copenhagen, DK
My research aims to contribute to the understanding of decadal- to orbital-scale climate dynamics and cryosphere-climate interactions during the past 150,000 years. My approach relies on polar ice core climate proxies linked to marine and terrestrial archive records to create spatio-temporal climate syntheses, and to climate modeling exercises. Such a multi-archive approach requires defining robust and coherent age models amongst the different archives. Hence, establishing reliable chronologies is also an important focus of my research.
My work is mainly guided by the following questions:
- How warm was the Earth’s surface during the Last Interglacial?
- What is the sensitivity of polar ice sheets to glacial-interglacial transitions?
- What is the sequence of changes from the low- to high latitudes across the abrupt Dansgaard-Oeschger events during the Last Glacial?
Georgia Institute of Technology, USA
Kim Cobb is the Georgia Power Chair and Professor in the School of Earth and Atmospheric Sciences at Georgia Tech, where she also serves as Director of the Global Change Program and as ADVANCE Professor for diversity, equity, and inclusion. Kim Cobb's research uses corals and cave stalagmites to probe the mechanisms of past, present, and future climate change. She received her B.A. from Yale University in 1996, and her Ph.D. in Oceanography from the Scripps Institute of Oceanography in 2002. She spent two years at Caltech in the Department of Geological and Planetary Sciences before joining the faculty at Georgia Tech in 2004. Kim has sailed on multiple oceanographic cruises to the deep tropics and led caving expeditions to the rainforests of Borneo in support of her research. Kim has received numerous awards for her research, most notably a NSF CAREER Award in 2007, and a Presidential Early Career Award for Scientists and Engineers in 2008. She is an Editor for Geophysical Research Letters, sits on the international CLIVAR Pacific Panel, co-chairs the US-CLIVAR Working Group on "Water Isotopes in the Climate System", and is a Lead Author for the IPCC Sixth Assessment Report. As a mother to four, Kim is a strong advocate for women in science, and champions diversity and inclusion in all that she does. She is also devoted to the clear and frequent communication of climate change to the public through speaking engagements and social media.
EPOC, Université de Bordeaux, France
Xavier Crosta is expert in diatom taxonomy, biogeochemistry and isotope chemistry to document Southern Ocean palaeo-oceanography and palaeo-productivity over the Pleistocene with a focus on the Holocene and last 2000 years. He is one of the leading researchers in the field of Antarctic sea ice reconstruction, whereby he developed a unique transfer function to quantitatively estimate past sea ice duration, to understand the drivers of sea ice dynamic and its feedback on global climate at millennial to decadal timescales.
Royal Holloway University of London, UK
My research focuses on understanding the links between climate change and ocean chemistry across timescales of thousands to millions of years during the Phanerozoic. I have a particular interest in using non-traditional isotope systems such as molybdenum, uranium, cadmium, osmium, rhenium and zinc to track changes in Earth’s biogeochemical cycles. Recently, my research has included looking at the interface of organic and inorganic geochemical techniques to understand the interactions between metals and organic matter in marine sedimentary deposits.
University of Cambridge, UK
Dr. Yama Dixit is a Research Fellow specialising in the area of palaeoclimatology at the Earth Observatory of Singapore. She is currently involved in developing Barium isotopes as a proxy for ocean productivity and reconstructing late Quaternary climate of Southeast Asia. Prior to joining EOS, she completed her PhD from the University of Cambridge, UK and was a Marie Curie postdoctoral researcher at IFREMER (Brest, France). Her research interests broadly lies in understanding the patterns and mechanisms of quaternary climate variability-in particular, Indian monsoon dynamics, changes in hydrology and effects on ancient societies and changes in Mediterranean rainfall.
University of Bremen, Germany
Thomas Felis is a senior scientist at MARUM – Center for Marine Environmental Sciences, University of Bremen, Germany. He works with annually-banded shallow-water corals to reconstruct past changes in temperatures and hydroclimate across the tropics to subtropics. He is interested in ocean-atmosphere interactions at timescales from seasons to decades, from millennia to hundred thousands of years. By using fossil corals of the Holocene, the last glacial and interglacial, his research focuses on modes of climate variability and integrates coral paleoclimate data with climate model output to understand processes driving past and future climate change.
Dept Earth Sciences, Stellenbosch University, South Africa
I conducted my PhD research at the Leibniz-Institute of Freshwater Ecology and Inland Fisheries and received a PhD in Natural Sciences from Humboldt Universität zu Berlin, Germany. Following postdoctoral stays at University of Essex, UK, and Universitat Autonoma de Barcelona, Spain, I moved to South Africa to join the Department of Earth Sciences at Stellenbosch University. My research includes using and improving proxies for the reconstruction of past climate and ecosystem responses and I focus mainly on biomarkers such as GDGTs and phytoplankton pigments. Sites of interest range from the continental Lake Baikal to the polar oceans and, more recently, areas under the influence of the Asian Monsoon.
McGill University, Canada
Natalya Gomez is an assistant professor at McGill University and a Canada Research Chair in the Geodynamics of Ice Sheet - Sea Level interactions. A geophysicist and climate scientist, her research centers around modeling the interactions between ice sheets, sea level and the solid Earth and understanding how these earth systems evolve in response to past, present and future climate changes. A highlight of her work has been to identify and quantify a feedback between sea level changes and marine ice sheet dynamics and explore its implications for ice sheet evolution and the interpretation of geologic and geodetic records in Antarctica.
Lamont-Doherty Earth Observatory, Columbia University of the City of New York, USA
My research interests lie in identifying and quantifying the impact of physical, dynamical and biological processes in the Southern Ocean on millennial- and orbital-scale atmospheric CO2 variations in the past, and how these processes were connected to climate variability in the northern hemisphere and low latitudes. I use a wide range of tools to study the Quaternary carbon cycle, including reconstructions of radiocarbon ventilation ages, parameters of the ocean carbonate system and deep-ocean oxygenation based on marine sediment cores. Currently, I focus on investigating ocean carbon cycle dynamics during (warmer-than-present) interglacial periods, especially the natural pathways by which the ocean may sequester carbon from the atmosphere.
Professor, Department of Earth, Atmospheric, and Planetary Sciences, Purdue University
My group (the Climate Dynamics Prediction Lab) and I work on developing a better understanding of—and ability to predict—the dynamics of the climate system with an emphasis on investigating past behavior as a window into future behavior. Much of this work focuses on atmosphere-ocean dynamics with an emphasis on hot conditions, e.g. the tropics and 'greenhouse' climates.
In addition to studying past warm climates, I have current active efforts in understanding heat stress and it's impacts on tropical societies as well as the influence of topography and land-use change on sustainability in urban and rural landscapes. Always in my mind is the implications of changing climates for life and humanity.
Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
Fumio Inagaki is a geomicrobiologist at Japan Agency for Marine-Earth Science and Technology (JAMSTEC). His research interests are geomicrobiology and biogeochemistry of the ocean, with special focus on the deep subseafloor biosphere. He uses scientific ocean drilling and transdisciplinary approaches to explore the limits and evolution of the deep biosphere, ecosystem functions in biogeochemical carbon cycles, and the planetary habitability of deep life on the Earth and beyond.
Simon Fraser University, Canada
Dr. Karen Kohfeld is known for her work using global palaeo-environmental datasets to understand the role of dust, ocean productivity, and circulation changes in glacial-interglacial climate and the carbon cycle. She received her PhD from Columbia University (USA) and was a research scientist at Lund University (Sweden), Max Planck Institute for Biogeochemistry (Germany), and Queens College (USA). A former Tier 2 Canada Research Chair, Karen formed the Climate, Oceans, and Paleo-Environments (COPE) laboratory at SFU in 2006, where she also investigates regional changes in climate, fire frequency, ocean acidification, and coastal and lacustrine carbon storage.
Alfred-Wegener-Institut, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Thomas Laepple received his Ph.D. in Physics in 2009 and worked since than as a PostDoc at the Alfred Wegener Institute for Polar and Marine Research and as a Feodor-Lynen Fellow at Harvard University. Since 2013 he is leading a Helmholtz Young Investigator research group and received the prestigious ERC starting grant in 2017. His present research interest lies in the quantitative synthesis and explanation of paleoclimate data. Bridging the gap between geological data and climate models, his working group develops a quantitative approach for the use of paleoclimate observations to reconstruct climate variability and to constrain estimates of future climate change.
Utrecht University, Netherlands
Lucas Lourens graduated in 1994 on Plio-Pleistocene climate changes in the Mediterranean Sea at the Utrecht University. His main research efforts focused on the influence and evolution of astronomically-paced climate changes during the Greenhouse and Icehouse Worlds of the Cenozoic, including the formation of Mediterranean sapropels, glacial-interglacial variability, early Eocene hyperthermals and the speed of the Earth's rotational axis on geological time scales. He participated in ODP/IODP expeditions to the Walvis Ridge (Leg 208) and Gulf of Cadiz (EXP 339). In 2011 he was appointed as chair of the Paleoclimatology group at the Faculty of the Geosciences, Utrecht University
University of Minnesota, USA
Katsumi Matsumoto is a Professor in the Department of Earth Sciences at the University of Minnesota. He uses physics-biogeochemistry coupled models of global ocean in order to probe carbon-climate feedbacks. The time period of interest spans the late Pleistocene, the modern, and the near future. Recently he has been interested in understanding how the plasticity of phytoplankton's chemical makeup affects the global ocean carbon cycle. He is trained in oceanography and low temperature geochemistry at Brown University (BS), University of Chicago (MS), and Columbia University (PhD).
University of Bergen, Norway
Nele Meckler is a paleoclimatologist specializing in the development and application of new temperature proxies in marine and terrestrial archives. She obtained her PhD in 2006 from ETH Zürich, where she investigated connections between the marine nitrogen cycle and climate. She then moved on to Caltech, where she used speleothems from Borneo to study tropical climate. There, she also became familiar with the clumped isotope proxy, which she has helped further develop since then, especially focusing on applications to paleoceanography. Over the last years, she has expanded the timescales she is investigating from the Pleistocene to the whole Cenozoic.
Victoria University of Wellington, New Zealand
Tim Naish was Director of the Antarctic Research Centre at Victoria University of Wellington between 2008-2017. His research is concerned with reconstructing orbital-scale sea level and polar ice volume variability using continental margin geological records. He works closely with ice sheet and climate modellers to understand the role of greenhouse gases and orbital forcing on ice sheet dynamics and their sensitivity. Presently, he is working on polar ice volume and global sea-level change during the Mid-Pliocene warm period and Late Pliocene global cooling associated with onset of the bi-polar glacial world.
Department of Earth and Atmospheric Sciences, University of Quebec in Montreal, Montreal, QC, Canada.
My research focuses on understanding past climate dynamics with particular focus on the last deglaciation, interpreting the signal recorded in proxy records with the help of climate models. I am currently working on the last African Humid Period assessing the role played by changes in dust and vegetation cover in altering regional and global climate and investigating the associated mechanisms. I also use global climate models to characterize variations in atmospheric and ocean circulation associated to large high-latitude and tropical volcanic eruptions.
School of Earth and Ocean Sciences, Cardiff University, UK
Paul Pearson is interested in the climatic and biotic evolution of the Cenozoic from a marine perspective. He studies the rich fossil record of planktonic foraminifera and is interested in their taxonomy, stratigraphy, paleobiology and geochemistry as carriers of paleoceanographic proxy information from the past. He has sailed on three ODP/IODP expeditions and conducted extensive fieldwork in many locations worldwide, most notably the clay-rich succession of Tanzania which contains exceptional records of tropical ocean conditions.
Summer Praetorius is a Research Geologist at the United States Geological Survey (USGS) in Menlo Park, CA. She received bachelor degrees in Geology and Anthropology from Portland State University, obtained a PhD in Oceanography from Oregon State University, and did postdoctoral research at Carnegie Institution for Science at Stanford. Her research focuses on developing high-resolution paleoceanographic records from the North Pacific in order to develop a better understanding of past climate dynamics in this region and their interactions with other components of the global climate system. Her research interests include the dynamics of abrupt climate change in the northern hemisphere, changes in ocean circulation, ocean hypoxia, and interactions between volcanism and climate in the past.
Royal NIOZ, Netherlands
Gert-Jan Reichart is head of the Ocean Systems department of the Royal Netherlands Institute for Sea research. Having worked with both organic and inorganic proxies his current research mainly focusses on the development and application of proxies for sea water conditions based on the incorporation of trace metals in foraminiferal calcite. This research also shows the strong organismal control of foraminifera on calcite precipitation and chemistry of this calcite. A major goal of his research is understanding how sea water carbonate chemistry influences foraminiferal calcification and vice versa.
I am a Japanese female geochemist who has been working for about 25 years in Europe, principally in France. I started my research career with modern marine geochemistry and then shifted towards paleoceanography and paleoclimatology. Currently, my major research theme is global oceanic circulation during the Holocene and late Pleistocene using neodymium isotopic composition recorded in sedimentary authigenic fractions and redox sensitive elements. Another research focus is the reconstruction of the hydrological cycle at low latitudes based on foraminiferal geochemistry and bulk sediment elemental composition with XRF scanning. Finally, I am also interested in proxy behaviours to improve the quality of reconstructions.
Brown University, USA
Kaustubh Thirumalai is a paleoceanographer whose research focuses on understanding past surface-ocean circulation as well as its interaction with atmospheric processes over decadal-to-millennial timescales. His work uses foraminiferal geochemistry to reconstruct sea-surface temperature and salinity over the Quaternary and uses a combination of statistical techniques and climate models to address mechanisms of climate change. Recently, Thirumalai has worked on the utility of individual foraminiferal analyses to investigate seasonal and interannual climate variability and associated ocean-atmosphere processes in the Indian Ocean.
IBS Center for Climate Physics, South Korea
Axel Timmermann, Distinguished Professor at Pusan National University (South Korea) was appointed Director of the IBS Center for Climate Physics in January 2017. Prior to his move to Korea, he was a Professor for Physical Oceanography at the University of Hawaii. Axel was awarded the Rosenstiel Award of the Rosenstiel School for Marine and Atmospheric Science and the Milankovic Medal of the European Geosciences Union. He was also lead author of the 5th IPCC Assessment Report. Axel is interested in a broad range of research topics ranging from past to future climate change, sea level rise and early human migration.
University of Bremen, Germany
Carbonate sedimentologist specialised in non-tropical carbonate systems. Research foci are (i) cold-water coral mound systems, their carbonate budget and environmental controls; (ii) the sedimentology of steep island shelves in mid-latitudes; and (iii) the development and application of computed tomography-based methodologies for the analysis of biogenic skeletons/shells and bioturbation traces within the sedimentary record.
University of Sydney, Australia
Jody Webster is Co-coordinator of the Geocoastal Research Group, in the School of Geosciences at The University of Sydney. His research focuses on coral reef systems, sea level and climate change, and tectonics around the world (e.g. Great Barrier Reef, Tahiti, Hawaii, Papua New Guinea, Seychelles, Brazil). His research is multidisciplinary in nature, encompassing traditional sedimentology and stratigraphy, combined with the novel use of marine geology and geophysics, paleoecology, geochemistry and numerical modelling. Jody is also heavily involved in the International Ocean Discovery Program (IODP) and is focused on recovering sediment cores from the seabed to understand past sea level and climate changes.
Nature Publishing Group, United States
I’m Nature’s editor for climate science. I came to Nature in 2008, after an academic career focused on land surface phenology, the terrestrial carbon cycle, and climate impacts. I handle all of our physical science submissions on atmospheres, oceans, the cryosphere and hydrology – past, present and future, on Earth and other planets. I also work closely with Nature’s editors for biogeoscience and ecology, and think of my expertise as being in Earth System Science, broadly defined, rather than in one particular area of climate.
The University of Hong Kong, China
Moriaki Yasuhara is an associate professor of environmental science in the School of Biological Sciences and the Swire Institute of Marine Science at the University of Hong Kong. He has broad interests in integrating organismal biology (ecology and evolutionary biology), paleontology, and paleoceanography/paleoclimatology, especially by using highly resolved micropalaeontological records. His recent research has focused on the spatio-temporal dynamics of large-scale biodiversity patterns, the impact of climate on species diversity, and the controlling factor(s) of biodiversity pattern/change in deep-sea, shallow-marine and pelagic ecosystems. He is also interested in microfossil-based conservation palaeobiology and palaeontology of the Ostracoda in general.
University of California, USA
James C. Zachos, Chair of Earth and Planetary Sciences at the University of California, Santa Cruz, received his Ph.D. in 1988 from the University of Rhode Island. His research explores aspects of ocean, climate, and carbon cycle dynamics over the Cretaceous and Cenozoic with a specific focus on periods of rapid and extreme climate change and issues ranging from the causes of extreme greenhouse warming and ocean acidification to the onset of Antarctic glaciation. He is a member of both the American Academy of Arts and Sciences and the National Academy of Sciences, and a fellow of the American Geophysical Union and the Geological Society of America. He is also a recipient of the AGU Emiliani Award and the EGU Milutin Milankovic Medal.
Multiple time scales of atmospheric CO2 variability in the late Quaternary
Ed Brook, Oregon State University, USA
Ice core carbon dioxide records underpin our understanding of the Quaternary Period carbon cycle. The iconic 800 ka EPICA Dome C record of glacial-interglacial CO₂ variability is now augmented by snapshots of older time periods from the Allan Hills (Antarctica) ice margin site, and by high-resolution data sets covering the last glacial period and Holocene periods. At Allan Hills, CO₂ concentrations have been recovered from discontinuous ice sections within the Mid Pleistocene transition (MPT) and in pre-MPT ice dated to 1.9-1.6 Ma. Within these sections CO₂ ranges from ~ 220 to 280 ppm; no CO₂ concentrations are as low as full glacial values or higher than full interglacial values of the last 800 ka are found.
High-resolution CO₂ data for the last glacial period from several ice cores show millennial and centennial variations during the last ice age in great detail. Important observations include: a) CO₂ and Antarctic temperature proxies in phase during the last glacial termination, b) millennial scale CO₂ variations correlated with Antarctic temperature proxies, but with a notable lag of CO₂ peak values relative to temperature, c) abrupt, centennial-scale increases in CO₂ that occurred during Heinrich stadials and Dansgaard-Oeschger warmings. High precision stable isotope data implicate organic carbon reservoirs (possibly in part terrestrial) for the source of Heinrich stadial increases, and suggest that CO₂ increases during DO events are caused by a combination of warmer sea surface temperatures and an organic carbon source (also possibly terrestrial). Recent results from the end of Marine Isotope Stage 5 suggest that the source that dominates during DO events may depend on the background climate state. These data also define a sequence of mechanisms that contribute to the drawdown of CO₂ at the MIS 5/4 transition
CO₂ and δ¹³C-CO₂ measurements for the Holocene show a slow increase in CO₂ and relatively constant δ¹³C -CO₂, which at face value do not support a large source from human activities. Decadal to centennial CO₂ variations in the Holocene, for example during the Little Ice Age, have isotopic signatures consistent with changes in the land carbon inventory.
Past climate influences on early human dispersal
Axel Timmermann, IBS Centre for Climate Physics, South Korea
Earth’s climate system varies on a wide range of timescales, from seasons to several millions of years. A large part of this variability is internally generated as a result of instabilities of the coupled atmosphere-ocean-ice-carbon cycle system. Other modes of variability, such as glacial cycles, are caused by the dominant Milankovitch cycles with periods of 20, 40, 100 thousand years. When these cycles conspire, they can cause major shifts in our climate, such glacial cycles or massive changes in tropical precipitation and vegetation.
To elucidate what role past climate and environmental conditions played in the dispersal of Anatomically Modern Humans out of Africa, we have developed and applied one of the first integrated climate/human migration computer models. The model simulates ice-ages, abrupt climate change, the "peopling" of our planet and captures the arrival time of Homo sapiens in the Levant, Arabian Peninsula, Southern China and Australia in close agreement with paleo climate reconstructions, fossil and archaeological evidence.
The human dispersal model simulates multiple prominent migration waves of Homo sapiens across the Arabian Peninsula and the Levant region around 106-94, 89-73, 59-47 and 45-29 thousand years ago. These waves were caused by earth's axis wobble and its corresponding changes in climate seasonality and resulting large-scale shifts in vegetation in tropical/subtropical regions. Such shifts opened up green corridors between Africa, the Sinai and the Arabian Peninsula, enabling Homo sapiens to leave Northeastern Africa and migrate into Asia, Europe, Australia and eventually into the Americas. The model also simulates a complex pattern of human dispersal out of Africa and back flow into Africa, that challenges the more unidirectional away-from-Africa perspective that is still very prevalent in anthropology and some genetic studies.
Paleo-genetic reconstructions indicate that the first successful exodus Out of Africa must have occurred around 70-60 thousand years ago. In contrast, our computer simulations and paleo-climate data show that northeastern Africa experienced one of its most severe long-term droughts during this time and may have been one of the least likely migration corridors. The resulting large desert areas would have been an impenetrable natural border for early human migration. Another unresolved issue in paleo-anthropology is the apparent late arrival of Homo sapiens in Europe around 40 ka.
Trends, Rhythms, and Aberrations in Global Climate 66 Ma to Present: Progress Toward a High-Fidelity Perspective
James Zachos, University of California, USA
The first deep-sea isotope records for the Cenozoic were published in the mid-1970s and, though very coarse, they captured the long-term trends in climate over the last 66 myr or so. In the time since, the international paleoceanographic community has made significant strides toward developing high-fidelity isotope and other records of Earth’s climate, with records extending back millions of years. Indeed, in just the last decade, several new astronomically tuned isotope records have been produced which capture variations in climate (and the carbon cycle) on orbital time scales for long segments of the early Cenozoic and latest Cretaceous. As with records for the late Cenozoic, they reveal a highly dynamic system undergoing constant change on a variety of time scales, but under much different boundary conditions of greenhouse gasses and continental configurations. Along with advances in reconstructing past pCO2, these new records are proving to be particularly useful for assessing the sensitivity of the climate system to orbital and greenhouse forcing, as well as providing context for the major climatic events, or anomalies and transitions (e.g., K-Pg, PETM, EOT, etc.), and thus identifying the origin of these events.
Reconstructing past marine life using ancient DNA
Linda Armbrecht, University of Adelaide, Australia
The study of ancient DNA (aDNA) from sediments (sedaDNA) is a new tool to characterise past marine life and environments from deep ocean sediments, and has great potential for paleoclimate research. Our own studies have identified a variety of pro- and eukaryotes that do not fossilise, revolutionising the scope of marine micropalaeontological research and allowing palaeo-communities to be examined. Recent improvements in ship-board sediment coring procedures have allowed far greater levels of contamination control and, along with refinements in aDNA sample processing, sequencing and bioinformatic techniques, now make the application of aDNA to marine sediments eminently realistic. We present an overview of the challenges involved in recovering authentic sedaDNA from marine sediments and outline best-practise techniques for seafloor coring and sample handling, as well as considerations for data generation. We also outline an optimised approach for the extraction of aDNA from marine sediments, achieving a broad eukaryotic biodiversity signal while retaining the highly-damaged small DNA fragments characteristic of marine sedaDNA. The use of metagenomics as well as RNA-based target-capture approaches to investigate past eukaryote communities will be discussed as a means to achieve a detailed view of marine community response to significant climate changes in Earth’s history.
Interglacial global and high-latitude temperatures: insights and perspectives
Emilie Capron, University of Copenhagen, Denmark
Over the past 400 thousand years, temperature reconstructions inferred from ice cores suggest an Antarctic warming during some warm periods, referred to as interglacials, of similar magnitude to that projected by 2100. Past interglacials are not strict analogues for future warming as they are controlled by different forcing mechanisms. Still, they provide an opportunity to assess with data, the effect of a warmer-than-preindustrial polar climate on the vulnerable parts of the Earth System e.g. ocean circulation, polar ice sheets and sea level.
In this talk, we will present recent progress in characterizing global and regional climate variations during the last interglacial period (129-116 thousand years ago), the most recent warm period when global sea level was substantially higher than it is at present. Those efforts combined surface temperature data syntheses based on reconstructions from polar ice and marine sediment archives and outputs from state-of-the-art climate models. They also required us to overcome the challenge to develop robust and coherent chronologies between climate archives.
First, quantitative estimates of the regional and global amplitude of the warmth throughout the Last Interglacial were produced based on the new data syntheses. Results suggest that across the globe (1) the maximum warmth was not synchronous and (2) the warmth amplitude was not homogeneous.
Second, model-data comparison exercises allowed identification of missing processes in climate simulations performed as part of the phase 3 of the Paleoclimate Model Intercomparison Project (PMIP3) to reproduce correctly the Last Interglacial climate evolution. Additional model experiments showed that a freshwater input into the North Atlantic (due to the Northern Hemisphere ice sheet early melting) needed to be accounted for in addition to the orbital and greenhouse gas concentration forcing in climate simulations, to explain the evolution of the early Last Interglacial climate.
Finally, our latest efforts aimed at providing appropriate data benchmarks to evaluate new and on-going Last Interglacial climate simulations performed within PMIP4, the new phase of the PMIP project. New model-data comparisons will be presented and will examine in particular the connections between large-scale and regional climate changes.
Overall, this presentation will illustrate how using a data-model approach enables progress on our understanding of the Last Interglacial climate. Next, this integrative approach will be extended to older interglacial periods as they also hold lessons about the impacts of a range of warm conditions on the different components of the Earth System and provide additional test cases for climate models outside their calibration range
Antarctic sea ice in the Pleistocene climate system: Drivers and feedbacks at different timescales
Xavier Crosta, EPOC, Université de Bordeaux, France
The waxing and waning of Antarctic sea ice, from a summer extent of ~3.10⁶ km² to a winter extent of 18.10⁶ km², represent the largest seasonal event on Earth. This seasonal cycle plays a fundamental role in regulating Earth climate through the modulation of key processes such as Southern Ocean overturning cells and global ocean circulation, Southern Ocean air-sea gas exchange (including CO₂), global ocean nutrient cycling (including carbon), Southern Hemisphere radiative balance, Southern Hemisphere atmospheric circulation and Antarctic ice-shelves stability.
Antarctic sea-ice extent has been slightly, but significantly, increasing over the past 40 years, at odds with climate models that estimate a decrease in Antarctic sea ice in the context of a warming planet. Despite discrepancies between observed and modeled sea-ice evolution over the satellite era, it is believed that Antarctic sea ice will decrease over the 21st century in response to rising air and ocean temperatures, thus impacting Earth climate globally. However, our understanding of the processes behind Antarctic sea-ice recent expansion is hampered by the brevity and sparse distribution of the observations that feed the reanalyses and climate models.
Paleoclimate data are therefore essential to document the natural variability of sea ice, its causes and its interactions with other compartments of the climate system under very different conditions and timescales. They are also pivotal to identify the pace of sea ice-climate responses under different mean conditions and at different timescales, as well as on the potential reversibility of these responses. I will here provide a substantive overview into the tools to reconstruct past Antarctic sea ice, the paleo-records, the drivers and climate feedbacks of sea ice changes from glacial-interglacial (last 200.000 years, warmer-than-present interglacial, Last Glacial Maximum) to decadal timescales (Holocene, last 2000 years). I will also briefly discuss the knowledge gaps.
Advances in paleo-ENSO: a past to future perspective
Kim Cobb, Georgia Institute of Technology, USA
A number of key questions surround future climate trends in the tropical Pacific Ocean, where interannual to decadal-scale variations in sea-surface temperature drive global temperature and precipitation variability with major implications for communities and ecosystems. The detection of potential anthropogenic trends in the mean state and variability of tropical Pacific climate is complicated by the short instrumental records of climate in this region, especially given its rich spectrum of intrinsic variability (e.g. Wittenberg et al., 2009; Newman et al., 2016). On the one hand, a variety of new paleoclimate reconstructions of ENSO – mostly derived from corals – reveal significant trends in ENSO-related variance from the pre-industrial era to the present, providing tantalizing evidence that ENSO properties may have already changed under anthropogenic forcing. However, these same records highlight significant decadal-, centennial-, and millennial-scale variability in ENSO and tropical Pacific mean climate, much of which is difficult to link conclusively to any of a number of sources of external climate forcings. With literally hundreds of coral paleoclimate records from across the tropical oceans already in hand, from a large diversity of sites and representing a panopoly of proxy applications, it seems appropriate to take stock of major accomplishments, lingering uncertainties, and future priorities for coral-based paleoclimate reconstructions. In this talk, I draw from dozens of coral paleoclimate studies in making the case that this area of research holds vast potential to accelerate our understanding of modern climate dynamics and climate change impacts. In particular, I focus on coral records and associated studies based at Kiritimati Island (2N, 157W), that span from 7,000 years before present to the end of the 2015/16 El Niño event. Key advances including the application of multi-proxy approaches, refinements to chronological assignments, and the development of coral diagenesis scorecards position the next generation of coral researchers to deliver on the full potential of the coral archive of climate. However, successive waves of heat-related coral mortality continue to erase decades to centuries’ worth of Earth’s precious coral archives with each passing decade. Indeed, almost all of coral climate archive that will be available to future generations of scientists has already been collected, and should be preserved and catalogued at all costs. As a scientist who has had the unique privilege of collecting many such cores, in a race with ocean warming that I would eventually lose in dramatic fashion, I end with some reflections on the scientist’s role in the drive towards climate stability.
Ocean-atmosphere variability since the last interglacial from annually banded corals
Thomas Felis, University of Bremen, Germany
The aragonitic skeletons of annually-banded shallow-water corals provide an ultrahigh-resolution archive of past changes in temperature and hydroclimate across the tropical to subtropical surface oceans. Coral records at monthly resolution allow reconstructing ocean-atmosphere variability and ocean-land interactions at seasonal, interannual and decadal timescales. Their absolute age control and resolved timescales make corals an important archive of tropical marine climate variability prior to the initiation of instrumental ocean observing systems. Cross-evaluating coral climate reconstructions with simulations by earth system models can place recent and projected future ocean-atmosphere variability and extremes into a long-term context. The last decade has experienced significant advances in coral proxy development and application. Logistically challenging reef drilling expeditions within IODP to retrieve glacial corals were successfully conducted. Significant progress in the use of fossil corals for climate reconstructions back to the last interglacial has been made, as well as in the application of advanced statistical methods to the increasing network of coral records within PAGES 2k. I will present examples of palaeoceanographic reconstructions from a global programme that uses modern and fossil corals from locations throughout the tropical to subtropical Indo-Pacific and Atlantic Oceans, including Southern Hemisphere sites such as the Great Barrier Reef and French Polynesia. The coral reconstructions address changes in seasonality, interannual to decadal variability, and mean climate. Time periods discussed include the last centuries, the late to mid Holocene, the last deglaciation to glacial, and the last interglacial. In combination with climate model simulations and observational climate datasets, these reconstructions shed new light on abrupt shifts in subtropical surface ocean hydrology during the last centuries and the pacing of surface ocean-deep ocean interactions such as deep-water renewals, reveal an abrupt multidecadal late Holocene excursion in tropical surface ocean temperature and hydrology, indicate changes in interannual variability and meridional gradients of tropical surface ocean temperature since the last glacial, and suggest an orbital control of changes in tropical surface ocean temperature seasonality during the last interglacial. Taken together, coral reconstructions contribute to a better understanding of the processes driving past and future tropical marine climate change on timescales relevant for society.
Understanding the wealth of GDGT-based proxies in paleoceanographic reconstructions, especially the more recently developed hydroxylated GDGTs
Susanne Fietz, Stellenbosch University, South Africa
membrane lipids synthesized by Archaea and some Bacteria. Since the early establishment of GDGT-based proxies, such as the TEX86 almost two decades ago, a wealth of GDGT-based proxies have been proposed. Changes in GDGT composition reflect different source environments, different microbial communities, and/or physiological acclimations of the microbes in response to environmental changes. Hence, each GDGT-based proxy arguably provides a different paleo-environmental information and a multi-proxy approach should allow teasing out complex interactions of physical, chemical and biological processes in the ocean. However, often enough, GDGT-based proxies indicate seemingly inexplicable environmental changes with time. Understanding the drivers of individual proxies is therefore key to the interpretation of such GDGT-based multi-proxy approaches. Here we present an overview of GDGT-based proxies, review the development thereof, and discuss benefits and caveats in paleoceanographic reconstructions. We then focus on the potential of newer proxies derived from structurally different GDGTs, e.g. OH-GDGTs. The latter are proposed to serve as temperature and sea-ice indicators, of particular importance in the cold waters of the Arctic and Antarctic Oceans where traditional paleothermometry is less reliable
Ice Sheet – Sea Level - Solid Earth Interactions
Natalya Gomez, McGill University, Canada
Modeling past ice sheet and sea level changes has classically been approached either by inferring ice cover changes through applying sea level modeling and comparing to geological sea level records, or by modeling the dynamic response of ice sheets to past climate changes. More recently, we have developed coupled models that simultaneously predict dynamic ice sheet evolution, global sea level changes and deformation of the solid Earth, and the feedbacks that arise between ice dynamics and sea level changes. These coupled models represent a new tool for self-consistently capturing regional ice sheet dynamics and their contributions to nearfield and farfield sea level changes globally, allowing for comparison to a wide range of geologic and geodetic datasets.
This talk will cover the interactions between ice sheets, sea levels and the solid Earth, and present recent work applying coupled modeling to give insight into ice sheet evolution and associated sea level changes over the last glacial cycle and during past warm periods such as the Pliocene. Results will focus on Antarctica, where there is extensive marine-based ice, and where complex, and laterally varying rheological structure of the solid Earth beneath the Antarctic ice sheet influences predictions of ice sheet evolution, sea level changes and modern glacial isostatic adjustment. The influence of sea level change and solid Earth deformation on Northern Hemisphere ice cover variations, and the potential for interhemispheric teleconnections between ice sheets to arise through sea level change will also be discussed.
The ‘yin-yang’ of paleoclimatology: proxy data versus numerical simulations, and their implications for the mechanisms of millennial-scale atmospheric CO2 change
Julia Gottschalk, Columbia University, USA
Numerical models are important tools for understanding the Earth system processes and feedbacks that have been responsible for past climate change. Model simulations can be inspired or constrained by (inherently sparse) paleoclimate proxy-data, which in turn are often based on empirical 'models' that are premised on a principle of uniformitarianism. A multitude of numerical model simulations have been performed, over decades, to probe the mechanisms of past atmospheric CO₂ (CO₂,atm) change. However, these often reveal inter-model and model-data mismatches that raise questions regarding outcomes that are model-dependent or represent non-unique ‘solutions’, and/or regarding the robustness of proxy-reconstructions. Here, we focus on millennial-scale CO₂,atm variations, and summarize the current paleo-proxy view on the (oceanic) mechanisms driving these changes. We show new complementary proxy-reconstructions of respired carbon changes in the deep South Atlantic during the last two glacial periods that emphasize a strong and systematic role for Southern Ocean vertical mixing and/or ocean-atmosphere CO₂ exchange in millennial-scale CO₂,atm changes that parallel North Atlantic climate anomalies. However, proxy reconstructions leave the two leading hypotheses explaining this link untested, that is, whether they are associated with: i) changes in the location and/or strength of the southern-hemisphere westerlies (i.e., an atmospheric teleconnection), and/or ii) changes in Atlantic overturning (i.e., an oceanic teleconnection). Given this proxy-data ambiguity, we compile 34 published model studies (consisting of 508 individual simulations) that assess the impact of these two mechanisms on millennial-scale CO₂,atm variations. While we find model agreement in the direction of simulated CO₂,atm change for the two types of forcing, the magnitude of CO₂,atm varies strongly between models due to different dominant processes. From a current model perspective, neither of these two forcing mechanisms likely worked in isolation to account for observed changes in CO₂,atm on millennial timescales in the past. However, a better integration of proxy data reconstructions and numerical model simulations may allow to overcome some existing limitations inherent to both approaches, and may ultimately be the key to fully understand the mechanisms of millennial-scale CO₂,atm change.
Paleoceanography reveals that Earth has no tropical thermostats but massive polar amplification of warming and sensitivity to forcing is difficult to explain
Matt Huber, Purdue University, USA
Looking broadly at paleoclimate records through the hothouse climates of the Eocene all the way through the Oligocene and on to the mid-Miocene reveals a much larger dynamic range of temperature at all latitudes, and hotter temperatures overall than often thought. Early Eocene warmth and Eocene-Oligocene cooling with ice sheet growth have been well studied and are ascribed to greenhouse gas forcing in combination with paleogeographic changes, although substantial model-data discrepancies remain. Moving into the late Oligocene and early to mid-Miocene, when many of the important ocean gateways and atmospheric carbon dioxide concentrations reached a more modern configuration, we should expect climate to have been much cooler than in the Eocene.
Compilation of paleotemperature records shows only a moderate cooling in the Miocene with respect to the Eocene and reveals global mean and high latitude temperatures that are warmer than the current generation of climate models can reproduce.
The implication is that models are not just missing a mechanism that enhances climate sensitivity and polar amplification in one warm climate, but across roughly 50 million years of Earth’s history across a range of geographies and greenhouse gas concentrations. It seems clear that we are still missing some key ingredient.
The role of the Southern Ocean in controlling ocean carbon uptake as the Earth entered the Last Ice Age
Karen Kohfeld, Simon Fraser University, Canada
Several mechanisms have been proposed to explain the 80-100 ppm decreases in atmospheric carbon dioxide (CO2) concentrations during glacial cycles, and many of these mechanisms focus on changes in the role of the Southern Ocean. Most proxy-based evaluations of these mechanisms focus on the peak of the Last Glacial Maximum, 24,000-18,000 years ago, and little has been done to determine the sequential timing of processes affecting the ocean uptake of CO2 as the Earth entered the last glacial cycle, between 127,000 and 18,000 years ago. While the exodus of carbon from the ocean occurs during rapid, deglacial bursts, the uptake of carbon by the ocean occurs over a series of steps, likely driven by a combination of processes. A global compilation of sea-surface temperature (SST) records help to establish the timing of ocean surface changes during the full glacial cycle, because this variable provides a critical link between the atmosphere and ocean, influencing processes such as air-sea gas exchange, buoyancy forcing, and sea ice formation. When compared with other observational constraints from sea ice and ocean circulation proxies, we can begin to develop a plausible sequence of events by which ocean carbon sequestration was enhanced during the last glacial cycle. We hypothesize that the initial major drawdown of 35 ppm of CO2, 115,000 years ago, was most likely a result of surface processes including early cooling impacts on air-sea gas exchange (as evidenced from temperature records) and Antarctic sea ice expansion (as evidenced from diatom-based records and ice-core proxies of sea ice). Importantly, changes in deep-ocean circulation and mixing – as evidenced from time-sequenced records of carbon and Nd isotopes - did not play a major role until at least 30,000 years after the first CO2 drawdown. The second phase of CO2 drawdown occurred ~70,000 years ago and was also coincident with the first significant influences of enhanced ocean productivity due to dust in the Southern Hemisphere, and these increases are shown to rival changes seen during the Last Glacial Maximum. Finally, minimum concentrations of atmospheric CO2 during the Last Glacial Maximum resulted from the combination of physical and biological factors, including the barrier effect of expanded Southern Ocean sea ice, slower ventilation of the deep sea, and ocean biological feedbacks.
Beyond mean climate change: Using paleoclimate archives to better constrain present and future climate variability
Thomas Laepple, AWI, Germany
Our planet is undergoing an unprecedentedly rapid transformation and, in order to adapt to the changing climate, we will need to know not only about changes in the mean state but also to the magnitude of climate variability. Whereas synoptic to interannual variations in the climate system are well documented, and current climate models are generally able to simulate them realistically, much less is known about the amplitude and mechanisms of climate variability on longer time-scales. Estimating that variability forms the basis for the detection and attribution of the anthropogenic component, determines the range of plausible future climate changes, and also provides information about the time-scales of the earth system components.
Paleoclimate archives such as corals and marine sediment records can provide the required information about climate variability, but they are sparse, inherently noisy and at times provide contradictory evidence. This hampers both the quantitative reconstruction of climate variability and the systematic testing of variability simulated by climate models.
In recent years, several advances have been made to better extract climate variability estimates from climate archives. These include a better characterisation of the non-climate effects on proxy records and of the proxy response to climate variations (based on replicate, multi-proxy and core-top compilations), proxy system models that bridge the gap between climate and proxy, and novel statistical techniques tailored to separate climate from noise components. Based on these advances we were able to considerably improve our understanding of present climate variability as well as to estimate how climate variability responds to a changing climate.
I will discuss recent advances in the toolbox for teasing out climate variability from marine proxy records and also point out future directions on how to enhance the use of the paleoclimate record for quantitatively constraining projections of the future climate evolution.
Hyperthermal events are tipping points for reorganization of global ocean circulation
Lucas Lourens, Utrecht University, Netherlands
The Early Eocene Climatic Optimum and its preceding late Paleocene to early Eocene warming trend encompasses the warmest time interval of the Cenozoic. Ocean temperatures were on average 8-10°C warmer than at present and atmospheric CO2 concentrations exceeded 3-6 times pre-industrial levels. Palaeoceanographic reconstructions revealed a highly unstable climate system, characterized by a series of orbital paced short-term global warming events of which the Paleocene-Eocene Thermal Maximum and Eocene Thermal Maximum 2 are the most prominent. The increase in global temperatures during these so-called hyperthermal events are generally linked to greenhouse gas forcing, since numerous biological elements are elevated in isotopically light carbon, pointing to the addition of large amounts of CO2 and/or CH4 into the ocean and atmosphere systems. Superimposed on the succession of hyperthermal events is a consistent +1‰ shift in deep sea benthic carbon isotope records within the EECO. This Early Eocene Carbon Shift (EECS) is enigmatic, since a concurrent shift in deep sea temperature is absent. In this talk, I will elaborate on the astronomical pacing of the hyperthermal events and their impact on the carbon pump and ocean circulation. I will furthermore discuss how these events slowly evolved during the late Paleocene to Early Eocene and triggered a remarkable tipping point in the climate system at the apex of the EECO.
Flexible stoichiometry of organic matter export on glacial carbon cycle
Katsumi Matsumoto, University of Minnesota
Ocean biogeochemists classically assume that phytoplankton biomass is composed of carbon (C), nitrogen (N), and phosphorus (P) in some fixed stoichiometry. Most global analyses and models of ocean biogeochemistry thus employ some fixed C:N:P stoichiometry, typically the Redfield ratio, for organic matter export. Recent large-scale studies indicate however that C:N:P ratio varies significantly on basin scales. Observations and theories suggest that C:N:P of organic matter export should vary as environmental conditions change, although the sense of change is not always well understood. For example, the physiological response of phytoplankton to diminishing supply of macronutrients is generally to increase their biomass C content. The same diminishing supply will generally change the phytoplankton community composition in favor of cyanobacteria, which typically have high C:N:P ratios, over eukaryotes, which have generally low ratios. Only recently has the field begun to explore how to represent flexible phytoplankton stoichiometry in global biogeochemical models and what the implications are for the global carbon cycle. Because the C:N:P ratio of organic matter is the gear by which nutrients drive the biological pump, the C:N:P variability has potentially significant implications on the global carbon cycle. I will present lessons and insights gained from applying a power law formulation of flexible stoichiometry to an earth system model of intermediate complexity under glacial conditions.
Clumped isotope thermometry in Cenozoic paleoceanography
Nele Meckler, University of Bergen, Norway
Clumped isotope thermometry is a relatively new addition to our toolbox for reconstructing past ocean temperatures. The advantage of this method is its thermodynamic basis and independence from additional factors, such as the composition of seawater. This makes it especially appealing for application on longer timescales, where other proxies are faced with largest uncertainties.
The use of clumped isotopes in paleoceanography, in particular with foraminifera, has previously been hindered by large sample amount requirements. However, more recent methodological advances have facilitated this application and spurred a number of studies bringing new insights into long-standing questions in Cenozoic paleoceanography.
In this talk I will give an overview over recent advances in clumped isotope methodology and ground-truthing efforts for application to foraminifera. I will then highlight some current work exploring surface and deep-sea temperature changes in key intervals of the Cenozoic, such as the middle Miocene or the Eocene-Oligocene Boundary, as well as the long-term evolution of deep-sea temperatures through the Cenozoic. In some cases the results reveal interesting discrepancies to previous estimates and thus yield new insights into the climate system through the Cenozoic era.
Mid-Late Pliocene global sea-level and polar ice sheet variability
Tim Naish, Victoria University of Wellington, New Zealand
Earth is rapidly heading towards a climate that was last experienced more than 3 Ma during the “mid-Pliocene warm period” (MPWP). During this time, global sea levels oscillated in response to orbital forcing with peak global mean sea level (GMSL) estimated at ~20 m above present according to previous studies from: (i) marine benthic δ18O records paired with Mg/Ca paleothermometry (proxy for global ice volume); (ii) an algorithm incorporating sill-depth, salinity and the δ18O record from the Mediterranean and Red seas; (iii) uplifted paleo-shorelines; and (iv) backstripped continental margins. These studies imply highly sensitive polar regions, under atmospheric carbon dioxide (pCO2) concentrations of ~350-400 ppm, resulting in melting of the Greenland (GIS), West Antarctic (WAIS) and marine based sectors of the East Antarctic ice sheets (EAIS). In addition to the considerable uncertainties inherent in these techniques, reconstructing Earth deformation processes caused by the redistribution of water between the ice sheets and the ocean, an cause local sea-level changes significantly larger or smaller than the ice volume contribution itself. Global mantle dynamic processes have also caused vertical land movements of tens of meters since the Pliocene. These processes now appear to cast significant doubt on our ability to estimate peak Pliocene GMSL, registered to present day.
A new sea-level record of glacial-interglacial variability for the mid- to late Pliocene, ~3.3 - 2.6 Ma, named PlioSeaNZ, has been developed from continuous, well-dated, highly-resolved shallow-marine sediment core and outcrop from Whanganui Basin, New Zealand. Water depth changes are reconstructed using a novel depth-dependent, sediment grain-size proxy for global ice volume. This is corrected for tectonic subsidence and subsequent compaction using a backstripping approach to determine the amplitude of relative sea-level (RSL) change. Glacio-isostatic adjustment (GIA) simulations of RSL change, show that the PlioSeaNZ record approximates eustatic sea level (ESL) - GMSL unregistered to the centre of the Earth. Our results provide new constraints for frequency, amplitude (discounted for mantle dynamics) and meltwater source of global sea-level variability during MPWP, late Pliocene global cooling and the onset of bipolar glaciation
The Green Sahara and its climatic consequence: from past to future
Francesco Pausata, University of Quebec in Montreal, Canada
In the Sahara and Sahel, rainfall is closely linked to the intensity of the West African Monsoon (WAM), which is crucial for the socio-economic stability of millions of people living in the region. Severe droughts have ravaged the region in the last three decades of the 20th century. However, our incomplete understanding of the complex interactions between global and local drivers of the WAM casts uncertainty in the prediction of future climate change. Past changes in WAM can offer an opportunity to better understand the mechanisms affecting its dynamics. One of the most dramatic changes in the WAM occurred between 12,000–5,000 years BP, when increased summer rainfall led to an expansion of the North African lakes and wetlands and an extension of grassland and shrubland into areas that are now desert, giving origin to the so-called “Green Sahara” or African Humid Period. However, model experiments have not been able to fully reproduce the intensification and geographical expansion of the WAM during this period and its potential teleconnections has hardly been investigated. In recent studies, we highlighted the feedbacks of land cover and the associated dust emission changes as critical factors in enhancing WAM strength as well as its far afield impacts on the El Nino-Southern Oscillation (ENSO) variability, tropical cyclone (TC) activity as well as Arctic Amplification. For example, we show through a modeling study that the strengthening of the WAM during the African Humid Period may have been able to reduce ENSO variability by up to 25%, more than twice the decrease obtained using orbital forcing alone (10%). We identify changes in tropical Atlantic mean state and variability as fundamental agents driving ENSO variations through changes in the Walker circulation. These changes in the large-scale circulation, and the thermodynamic and kinetic state of the atmosphere also have strong impacts on worldwide TC development. The African Humid Period offers a unique opportunity to leverage the past to elucidate the implications of a potential natural or geoengineered regreening of the Sahel and Sahara region.
The role of North Pacific Ocean variability in abrupt deglacial climate events
Summer Praetorius, USGS, USA
Abrupt fluctuations in past oceanic conditions in the Northeast Pacific coincide with rapid climate fluctuations in Greenland and the North Atlantic Ocean. However, Northeast Pacific changes have traditionally been viewed as a response to changes in North Atlantic circulation rather than as a possible driver of abrupt Northern Hemisphere change. Here we investigate how surface ocean conditions evolved with deep-water ventilation changes in the Northeast Pacific throughout the last deglaciation to provide greater insight into global ocean circulation dynamics and the North Pacific’s role in abrupt deglacial climate events. A primary objective is to determine the timing of local-to-regional sea surface freshening along the Northeast Pacific related to Cordilleran Ice Sheet meltwater and Columbia River megaflood events. We compile high-resolution reconstructions of sea surface temperature (SST), paleo-salinity, and deep-water radiocarbon from the Northeast Pacific to examine water column circulation changes, and place these regional changes in the context of global SST patterns during major climate events of the last deglacial period. Our synthesis reveals that surface ocean freshening and cooling occurred in the Northeast Pacific during the early deglacial (19-16 ka) and Younger Dryas (12.9-11.7 ka) periods, with accompanying increases in the Benthic-Planktic (B-P) radiocarbon age of subsurface water masses. Conversely, we find abrupt SST increases during the Bølling-Allerød and early Holocene transitions, with an accompanying decrease in B-P age of water masses in the Northeast Pacific. Global SST patterns show large variations in SST along the Northeast Pacific margin that occur in conjunction with abrupt temperature changes in Greenland and the North Atlantic for the Bølling-Allerød warming, Younger Dryas cooling, and Holocene warming transition, whereas the early and late phases of Heinrich Stadial 1 show more heterogeneous SST patterns between the North Pacific and North Atlantic. SST changes in the western Pacific are more divergent from the dominant trends in the Northeast Pacific, North Atlantic, and Greenland. These patterns are not wholly consistent with modeled climate anomalies based on simulated North Atlantic circulation changes, suggesting ocean dynamics in the North Pacific played an integral role in abrupt Northern Hemisphere climate reorganization.
Calcification feedbacks on the global carbon cycle
Gert-Jan Reichart, Royal NIOZ, Netherlands
The composition of the shells and skeletons of marine calcifyers, including that of foraminifera, markedly differs from that of inorganically precipitated CaCO3 This reflects the tight biological control on calcification, which is so far only partly understood, but hampers our understanding of the relation between environmental conditions and shell chemistry and thereby, foraminiferal proxy calibrations. The cellular processes involved in calcification include the involvement of organic templates, trans-membrane ion transporters and proton removal. Recent results suggest that exchange of H+ for Ca2+ across the protective envelope drives calcification. It supplies calcium ions to the site of calcification, but in addition, the high pH gradient between inside and outside the foraminiferal cell allows efficient CO2 trafficking over the cell membrane. Upon entering the site of calcificaiton, the CO2 is converted to carbonate , thereby elevating the saturation state and promoting calcite precipitation. This mechanism explains how some foraminifera are able to calcify in undersaturated seawater and also the limited response of some species to ocean acidification. At the same time this also implies that elevated marine dissolved inorganic carbon and the resulting decreased pH do not necessarily result in reduced shell production in a high CO2 world.
Intuitively, high pCO2 should decrease the ability of CaCO3-producing organisms to build their skeletons and shells. This provides a potential negative feedback on time scales up to thousands of years. Whereas on geological time scales weathering and carbonate deposition removes carbon from the geo-biosphere, on shorter time scales carbon speciation changes in seawater. Reduced calcification dampens the effect of increased pCO2 because as seawater carbon speciation shifts towards bicarbonate. Active proton pumping by foraminifera to form their calcium carbonate effectively uncouples saturation state from calcification and predicts that the added carbon due to high pCO2 might in fact promote calcification by these organisms. This still not fully understood feedback could provide a positive feedback on atmospheric pCO2 levels on time scale up to tens of thousands of years.
Neodymium isotopic composition as a proxy of water mass provenance in the Atlantic Ocean: the modern ocean and the past 1200 kyr
Kazuyo Tachikawa, CEREGE, France
Neodymium isotopic composition (143Nd/144Nd or Nd) is one of the most widely used tracers to reconstruct ocean circulation and detrital inputs to the ocean. In this presentation, I will address the following topics by taking the Atlantic Ocean as an example: the distinction between conservative water mixing and local/regional Nd effects on seawater Nd; an assessment of sites where local/regional Nd inputs dominate; the combination of Nd with foraminiferal 13C to investigate changes in oceanic circulation and the carbon cycle across the Mid-Pleistocene transition (MPT).
Based on the present-day seawater database, the relationships between Nd and other water mass tracers (13C-DIC, nutrients, dissolved oxygen, 14C, temperature and salinity) were determined for the Atlantic deep waters (≥ 1500m). Using multiple regression analysis, empirical equations were established to predict the large-scale deep-water Nd trends from hydrographic parameters. The spatial distribution of significant local influence can be estimated as large offsets from the predicted values. The results indicate that deep waters in the northern subpolar Atlantic, close to Greenland and Iceland, are highly affected by local inputs. The authigenic Nd values (foraminiferal oxides, fish teeth/debris, dispersive oxides) more frequently present an isotopic composition that deviates from expected values, often with a positive bias. This suggests a contribution of exchangeable radiogenic Nd from the detrital fraction to pore water and to authigenic fractions. To examine whether sites are suitable for using Nd to evaluate water mass provenance, systematic comparison of core-top values with present-day seawater is recommended. Finally, two eastern Atlantic Nd records were generated and combined with benthic foraminiferal 13C values to evaluate the role of deep-water circulation across the MPT. By comparing with existing data, the 900-ka event is suggested to be related to a reduced contribution of northern source water with slower circulation that allowed accumulation of respired carbon in deep waters. Thus, ocean circulation and carbon cycle changes seem to have contributed to the climate shift associated with the MPT.
An Indian Ocean El Niño?
Kaustubh Thirumalai, Brown University, USA
Despite minor variations in sea-surface temperature (SST) compared to other tropical regions, coupled ocean-atmosphere dynamics in the Indian Ocean cause widespread drought, wildfires, and flooding. It is unclear whether changes in the Indian Ocean mean state can support stronger SST variability and climatic extremes. Here we focus on the Last Glacial Maximum (19,000-21,000 years before present) when background oceanic conditions could have been favorable for stronger variability. Using individual foraminiferal analyses and climate simulations, we find that seasonal and interannual sea-surface temperature variations in the Indian Ocean were much larger during this glacial period relative to modern conditions. The increase in year-to-year variance reflects the emergence of an equatorial mode of variability resembling the Pacific El Niño, which is not currently active in the Indian Ocean. Future activation of this El-Niño-like mode could have crucial impacts on climate extremes over the heavily populated Indian Ocean rim.
Cold-water coral mounds – carbonate factories and palaeoarchives in intermediate water depths
Jürgen Titschack, University of Bremen, Germany
Cold-water coral mounds, formed by azooxanthellate framework-building scleractinian corals, cluster in mound provinces at 200-1000 m water depth along almost all continental margins but are especially common in the Atlantic Ocean. A newly-developed approach using 3D computed tomography data allows to quantitatively analyse their internal composition and complex formation history. Due to their widespread distribution and carbonate contents of 50%, coral mounds present globally important carbonate factories. Maximal aggradation and carbonate accumulation rates in the range of shallow-water coral reefs highlight their importance as carbonate sink in intermediate water-depths, though their contribution to and function within the global carbon(ate) cycle still lacks a comprehensive evaluation.
In addition, being bathed in central water masses, coral mounds present so far underestimated but promising palaeoceanographic archives, which exhibit extremely high temporal resolutions during phases of fast mound aggradation. Their composition made up of corals embedded in hemipelagic sediments provide two independent proxy sources. In particular, the absolute Uranium-series dating of the aragonitic coral skeletons allows the establishment of precise age models going back to 500 ka BP. Combining palaeoceanographic records from coral mounds and the adjacent seafloor furthers our understanding of the climate-related evolution of the central water masses. This is of major interest with respect to their important role as heat reservoirs, which is expected to absorb about one-third of the ocean heat uptake in the near future.
The response of coral reef systems to sea level rise: lessons from the past to better predict the future
Jody Webster, University of Sydney, Australia
Fossil coral reefs provide important evidence about the former positions of sea level in space and time due to their geological preservation and suitability for dating. Of particular interest is the use of submerged coral reefs to: (1) reconstruct the timing, rate and magnitude of sea level rise to better understand the dynamic behaviour of past ice sheet melting, and (2) assess the impact of sea level rise and associated environmental changes that cause coral reef drowning (i.e. inability to keep pace with sea-level rise). Understanding how and why coral reefs drown is vital to the recognition and quantification of rapid sea-level rise associated with meltwater pulses (MWP’s) that have been controversially linked to the catastrophic collapse of ice sheets in the past. Studies of drowned fossil reefs from Barbados, Tahiti, Huon Peninsula, Hawaii and elsewhere have produced a broadly consistent picture of ice melt, reflecting eustatic change since the Last Glacial Maximum (LGM). However, despite the International Ocean Drilling Program (IODP) expeditions to Tahiti (Exp. 310), and most recently the Great Barrier Reef (GBR) (Exp. 325) extending these records, considerable uncertainty remains concerning the details, nature and impact of deglacial meltwater pulses on coral reef systems. These studies have shown that the sensitivity of reefs to rapid sea-level rise varies considerably, with some reefs drowning while others do not. In this seminar, I present a synthesis of key geomorphic, sedimentologic, biologic, geochemical, dating and numerical stratigraphic modeling data from submerged coral reefs around the world and explore the issue of how and why coral reefs drown. Focusing on the GBR, I will investigate the nature and timing of successive reef demise events, and argue that the synergistic effects of sea level rise (i.e. poor water quality) have been crucial in ultimately causing reef drowning and demise over the past 30,000 years. Finally, I also highlight the exciting potential of the next major IODP coral reef drilling project - Expedition 389 (Hawaiian Drowned Reefs) likely to be scheduled 2020-23 to produce an unparalleled record of sea level changes and ice sheet dynamics over past 500,000 years.
Deep-sea drilling perspective on paleobiology: "co-evolution" of paleoceanography, paleoecology and macroevolution
Moriaki Yasuhara, The University of Hong Kong China
Deep-sea drilling has given us spectacular time series records of past climate. For example, we know ocean temperature history throughout the Cenozoic for the last 65 million years, and also have accurate reconstructions of millennial–centennial scale climate changes for the last tens to hundreds of thousands of years. The modern development of deep-sea drilling and paleoceanography since 1980–90s has changed our understanding of Earth history. Moreover, it is changing our understanding of the biosphere into four full dimensions. Deep-sea sediment cores include microfossils, biological remains of the benthos and plankton, allowing direct comparison of biotic and climatic changes on various time scales in any part of the Cenozoic. Additionally, molecular phylogeny addresses similar time-scale macroevolution, and can now be directly compared to robust and quantitative climatic records, something that was impossible in the last century. It is not surprising that tighter integration of paleoecology and macroevolutionary research with paleoceanography has been rapidly progressing, given that all these research fields have now matured. In this presentation, I showcase several examples of this modern integration, including orbital climate control of biodiversity; temporal dynamics of latitudinal diversity gradients; and ecosystem response to abrupt climate change. I show the prospect of further "co-evolution" of these promising fields and their integration, with special focus on microfossil crustacean ostracods, the only metazoan with sufficient fossil preservation and records for this purpose.
Holocene history of the Indian summer monsoon – perspectives from northwestern India
Yama Dixit, University of Cambridge, UK
The Indian summer monsoon (ISM) system is a critical part of the global hydrological cycle. Variations in the intensity of the summer monsoon are likely to have widespread socio-economic impacts on the Indian subcontinent, underlining the importance of examining the variability of monsoon on various timescales. The northwestern India today receives over 80% of the rainfall from the ISM and exhibit a steep precipitation gradient spanning sub-humid, semi-arid to arid plains. Lacustrine archives preserved across these plains can help evaluate past changes in monsoon, both in terms of its cyclicity and intensity, and elucidate its potential societal implications, in what was one of the most densely populated regions in the world during the mid-late Holocene. Paleoclimate records from these lakes show early Holocene onset of intensified monsoon in NW India, similar to that reported from other ISM records, following the precession driven boreal summer insolation. Distinct abrupt monsoon weakening events between 8.2–8.0 and 4.2–4.0 kiloyear BP also characterize the reconstructions. The timing of occurrence of the 8.2 ka drought coincides with the beginning of the ‘8.2-ka cooling event’ in the North Atlantic that has been associated with a glacial outburst flood and slowdown of Atlantic meridional overturning circulation. We suggest that changes in the tropical ocean phenomena, persistent El-Nino Southern Oscillations (ENSO) conditions in the tropical Pacific and the Indian Ocean Dipole (IOD) in the Indian ocean weakened the boreal summer monsoon circulation by inducing subsidence and rainfall suppression over the Indian subcontinent around 4.2 ka BP. Expression of these abrupt climate events in monsoon reconstructions suggest that the strength of the ISM is determined by complex interplay of high and low latitude climate anomalies. The Holocene history of the ISM closely follows the cultural transformations in this region highlighting the significance of natural climate variability as one of the factors affecting ancient human settlements.
Wombeyan Karst Conservation Reserve
Saturday 7th, Sunday 8th (depending on numbers)
Cost: $100/person (includes transport and entry to the caves)
Start from/return to UNSW: (~3.5 hours drive) by bus
Min/Max number of persons: 20-45
The Wombeyan Caves are situated between Taralga and Mittagong. They became the first protected caves in Australia in 1865. The tour will include a guided cave (Kooringa) and a self-guided cave (Fig Tree Cave). For the more adventurous participants, the self-guide cave (Tinted Cave), followed by a strenuous undulating bush-walk to our research cave (Wildman’s Cave) and return would be another option.Register for The Wombeyan Caves
Attendees need to be physically fit as this field trip includes a strenuous bush-walk of a few km, including steep slopes, steps and vertical fixed ladders.
What to bring: Water, packed lunch and snacks for the day. Appropriate clothing for bush-walking (hiking boots, sun hat, sun screen, backpack for water bottles and snacks). Please be aware of snakes and dress accordingly. There is a kiosk at the Wombeyan Caves that sells a very basic range of food (canned drinks, ice cream, microwave pies, coffee, etc.). Water is available on-site, but we would recommend to pack enough water and food for your needs for the whole day.
Children: Delegates with young families could choose to take the coach and not do the all (or even any) the tours, and instead enjoy the wildlife and some shorter walks on site. Hundreds of very tame kangaroos are guaranteed. Wombats, snakes, echidna, lyre birds, possums and gliders are all possible.
Adventurous delegates could choose to hire a 4WD (at their own time and expense, the airport is normally the best place for 4WD) and take the Wombeyan Caves Road (at their own risk) and meet the coach group there. https://en.wikipedia.org/wiki/Wombeyan_Caves_Road. It’s 1.5 hours of amazing scenery and dirt road. Drivers will meet at UNSW at the same time, and will drive in a convoy, meeting the coach at Wombeyan.
There is no mobile coverage by any service provider. There is no wireless or internet of any kind. There is one public pay phone on site. There are no shops within one-hour drive. Nearest hospital is at Goulburn Base Hospital (>1 hour drive). Helicopter landing is possible.
Surfing on Bondi Beach
Sunday 1 September and Saturday 7 September
Duration: 2 hours
Cost: $95 pp
The golden sands and crystal waters of Bondi continue to capture hearts all around the world. As Bondi’s only officially licensed surf school on Australia’s most famous beach, the team of passionate and experienced Surf Instructors have been changing lives one wave at a time since 1995. Home to Australia’s oldest surf lifesaving club, funky beach vibe bars and restaurants, urban-style shops, hip markets, Lets Go Surfing and Bondi is an experience not to be missed. Australia’s greatest surf experience on Australia’s Greatest Beach!
Please click here to book your surf experience now!
Coogee to Bondi Walk
Saturday 7 September 2019
Duration: 3 hours
A cliff top coastal walk, the Coogee to Bondi walk extends for 6 km in Sydney’s eastern suburbs. The walk features stunning views, beaches, parks, cliffs, bays and rock pools. The beaches and parks offer a place to rest, swim or a chance to eat at one of the cafes, hotels, restaurants or takeaways. Most beaches offer picnic shelters, play areas, kiosks, toilets and change-rooms, Tamarama, Bronte. The Coogee to Bondi coastal walk is a medium grade urban walk but there are some steep gradient paths and several staircases along the track. There are rest stops with great views and seating along the coast.
Meet Saturday 7 September at 10am at the Coogee Beach Stairs. Please click here to see a photo of the meeting point.
Pub Crawl around the Rocks
Sunday 1 September 2019
Duration: 3.5 hrs (from 1800 till 2130)
Cost: $87.50 incl meal pp
Between watering holes, your guide takes you through the alleys and cobbled streets of The Rocks as they share the gossip, shouts, and stories of Australia’s first European settlement. Hear about the legends, gangs, and hauntings of this distinctive neighbourhood as you sample some of its finest libations. Click here to get an idea of this awesome experience.
This tour includes a choice of a beer, house wine, or soft drink at each pub – and one meal – as well as a guided walking tour of The Rocks
Please contact the ICP13 Conference Secretariat to book your spot – firstname.lastname@example.org
Sunday 1 September and Saturday 7 September
Duration: 2 – 3 hours
Cost: From $70 pp
The ultimate Whale experience! Whale watching time is maximized with this cruise as it only takes 15 minutes from Circular Quay to the open ocean. The humpback whale (Megaptera novaeangliae) is a species of baleen whale. One of the larger rorqual species, adults range in length from 12–16 m (39–52 ft) and weigh around 25–30 metric tons (28–33 short tons). The humpback has a distinctive body shape, with long pectoral fins and a knobbly head. It is known for breaching and other distinctive surface behaviours, making it popular with whale watchers.
Please click here to book your 2 or 3hr Whale Watching Experience now!
Use promo code ICP13-2019 to get a 10% discount!
Opera House tour
Wednesday 3 September
Duration: 1 hour (from 1445 till 1545)
Cost: $40 pp
Fusing ancient and modernist influences, and built on a site sacred to the local Gadigal people for thousands of years, the sculptural elegance of the Sydney Opera House has made it one of the most recognisable buildings of the twentieth century, synonymous with inspiration and imagination.
Today it is Australia’s number one tourist destination, welcoming more than 8.2 million visitors a year and one of the world’s busiest performing arts centres, presenting more than 2000 shows 363 days a year for more than 1.5 million people, from the work of the seven flagship arts companies to which it is home to First Nations’ arts and culture, talks and ideas, theatre and dance and the superstars of classical and contemporary music.
Please contact the ICP13 Conference Secretariat to book your spot – email@example.com
One Tree Island
Monday 8 – Friday 12 September
Duration: 4 nights, 3 full days on the island
Cost: $1,010 per person excl flights (min 12, max 23)
Would you like to go on a remote reef ICP13 adventure to the One Tree Island Research Station?
Imagine the perfect desert island getaway, complete with a turquoise lagoon out your front door, the vistas from One Tree Island Research Station approach that. It is a small station with 24 beds, and it is adventure simply getting there. There is no regular ferry to One Tree Island and no deep water pass through the reef platform, for this reason the station only has a few visitors each year. Getting on to the reef and hence the Station is dependent on the tides. This also means we will have to transfer to a smaller boat from the ferry to reach the research station. For health and safety reasons children, people with mobility issues and those that should not be more than several hours from serious medical care should not apply to come on this field trip.
One Tree Island is a windward rubble island and ‘storm-born’. The reef platform is emergent at low tide, so walking around the reef platform is relatively easy, if you have proper foot ware. We recommend bringing dive boots with heavy soles for this purpose. The snorkelling is excellent around the station and around the platform and we will be taking the station boat out to several dive sites during our stay.
The field trip will be led by Bradley Opdyke. Dr. Opdyke has led University courses out to Heron and One Tree reefs for over 20 years and will be happy to lead tours and lecture to interested parties the Quaternary history of the reef and the region.
The Station’s accommodation is bungalow style, with 2 bunk beds in most rooms. You would be expected to bring a pillow case and a set of sheets for a single bed. The group will share the cooking and cleaning and we will be happy to consult about the menu with you. More detailed information here.
We will all rendezvous in Gladstone (QLD) at 1300 on Sunday 8 September. The boats will be leaving early on Thursday 12 September to return to Gladstone (QLD).
Please note: travel insurance and flexible flights are strongly recommended because there is the remote possibility that weather could prevent departing from the island for a day or two.
BYO Alcohol, BYO Snorkelling mask, fins, dive boots, and wetsuit, BYO sheets and pillow case.
Please contact the ICP13 Conference secretariat by 14 June to arrange your booking.
Proxy development, new model and statistical tools
Geobiology- new frontiers in paleoceanography linking paleoclimatic changes with biology and evolution
Carbon-climate feedbacks across time scales
Ocean circulation and climate system dynamics
Role of Southern Hemispheric processes
Ice-sheet/ocean interactions: drivers and impacts
|Social Functions||Field Trips||Breaks|
The ICP13 will include five half-day plenary sessions and three extensive poster sessions and will include the following themes:
1. Proxy development, new model and statistical tools
The paleoclimate toolbox has expanded considerably over the past few decades. There are now a wide variety of proxies from microfossil assemblages, sediment properties, stable isotopes, trace metals, radiogenic isotopes, and organic biomarkers. Proxy development has also gone hand in hand with an improved understanding of how both biological and chemical proxies function as carriers of environmental information.
Statistical techniques have also advanced, providing better inference models based on the relationships between these proxies and the targeted environmental variables. Climate and Earth system models now incorporate more complex processes and have higher spatial resolution. Thus, a range of oceanic physical, chemical, and biological processes can be examined, to better understand their influence on climate-relevant variables.
This session will showcase the latest advances in this broad field, by welcoming presentations about the calibration and application of new proxies, along with novel statistical and modelling approaches, and their usage in teasing out and interpreting paleo-environmental information from all available archives and model experiments.
2. Geobiology- new frontiers in paleoceanography linking paleoclimatic changes with biology and evolution
Geobiology describes the interaction between the physical Earth and the biosphere. By combining information about the past development of more than one species, geobiology offers the opportunity to explore the dynamics of biological communities over long temporal periods. Geobiology has recently benefitted from major methodological and analytical advances, e.g., ancient DNA (aDNA) and novel modelling approaches. Yet, we are just at the beginning of understanding past marine ecosystem developments (or evolution) as well as the forcing and feedbacks between the biological and physical environment. Making full use of the potential of geobiology may significantly enhance ecological interpretations and our understanding of ecosystem responses to climate change – also in the future.
We invite contributions that address past developments of marine biological communities and their environment based on all types of biological proxy records ranging from standard paleoecological methods to new proxy developments.
3. Carbon-climate feedbacks across time scales
The Earth climate history is characterized by long-term gradual changes interrupted by more abrupt climatic transitions. These abrupt changes were mostly accompanied with significant variations in atmospheric pCO2 and carbon perturbations. However, the mechanistic links and feedbacks between climate and the carbon cycle remain elusive, warranting further in-depth understanding of interactions of processes governing the ocean-ice-atmosphere-solid earth system using a variety of archives (e.g., ice cores and marine and terrestrial deposits) and methods (proxies and numerical models).
This session invites contributions that improve our understanding of carbon-climate feedbacks across all timescales. It encompasses, but is not limited to, atmospheric pCO2 reconstructions, variations in the strength of the marine biological pump, air-sea CO2 fluxes, climate sensitivity, changes in ocean surface and interior carbon storage, solid earth influences, terrestrial biosphere changes, and proxy-model based quantification of timing and magnitude of global ocean carbon changes during the Cenozoic.
4. Ocean circulation and climate system dynamics
Climate is largely governed by ocean dynamics over a wide range of spatial and temporal scales. In particular, the ocean circulation plays a central role in climate dynamics through air-sea interactions, transport of heat and salt, and storage of heat and carbon. Reconstructing the ocean's past is critical for understanding the dynamics of the climate system as a whole.
This session welcomes presentations focusing on ocean circulation and its links with the climate system dynamics. We seek contributions encompassing observational, theoretical, and modelling studies of ocean circulation in the past, present and future, with a particular focus on: (1) paleoceanographical reconstructions on various timescales and derived from marine paleo-proxies; (2) key processes that could force or generate changes in ocean circulation; (3) Impact of changes in the oceanic circulation on climate system dynamics (e.g. ENSO, Monsoons…); (4) developing and applying numerical models to simulate changes in ocean circulation and its impact on climatic changes.
5. Role of Southern Hemispheric processes
Since the formation of the Southern Ocean during the early Oligocene, the Antarctic Circumpolar Current (ACC) has provided an unique link that connects all the major ocean basins. Two of the main water masses that are part of the global meridional ocean circulation are formed at high southern latitudes: Antarctic Bottom Water and Antarctic Intermediate Water. Variations in the formation and transport of these water masses and of the ACC have a significant impact on climate and the carbon cycle. In addition, Southern Ocean biological productivity potentially also exerts a significant control on the global carbon cycle.
Processes occurring in the tropical Indo-Pacific are also a major driver of climate variability. Modes of variability such as El Niño Southern Oscillation strongly impact tropical to mid-latitude hydrological cycle. However, changes in these mode of variability are poorly constrained for many time periods.
For this session, we invite contributions from both proxy reconstructions and modelling studies, which advance our knowledge of Southern Hemispheric processes and their impact on climate and biogeochemistry across Cenozoic and Quaternary timescales.
6. Ice-sheet/ocean interactions: drivers and impacts
Sea-level rise is perhaps one of the most alarming repercussions of present-day climate change. It is therefore necessary to gain a more thorough understanding of the dynamics of continental ice sheets, including the complex interactions between buttressing ice shelves, ocean circulation and warming ocean waters, in order to increase our confidence in future sea-level and climate projections. Moreover, the sizes and geographic distributions of continental ice sheets determine an important slow feedback in the radiative balance of climate, which needs to be resolved for a better understanding of climate responses relative to radiative changes. This session is a focal point for studies on ice-sheet variability, ice-ocean interactions, crustal deformation, and ice-sheet impacts on climate, from radiative feedbacks to changes in ocean and atmospheric circulation, marine productivity, and the carbon cycle.
For this session, we invite contributions from both reconstructions and modelling, which shed light on the role of ice-sheets in climate sensitivity and ice ocean interactions from regional to global scales.
- Call for Abstracts Open1st September 2018
- Super Early Bird Registration1st – 7th September 2018
- Early Bird Registration8th September 2018
- Early Bird Registration Close17th March 2019
- Standard Registration18th March 2019
- Call for Abstracts Close1st May 2019
- Final Notification of Abstracts17th May 2019
- Final Presenters Registration Date24th May 2019
- ICP13 2nd – 6th September 2019