Wed 12 Feb 17:30: Climate-ice sheet interactions in the long-term past and their importance for the long-term future
The simulation of the last deglaciation (about 20.000 years before present to present) represents a hitherto unsolved challenge for comprehensive state-of-the-art climate models. During my presentation, I will introduce our novel coupled atmosphere-ocean-vegetation-ice sheet-solid earth model that is used to simulate the transient climate. An ensemble of transient model simulations successfully captures the main features of the last deglaciation, as depicted by proxy estimates. In addition, our model simulates a series of abrupt climate changes, which can be attributed to different drivers that will be discussed throughout the presentation. I will furthermore show, how the model can be applied for simulations of the long-term future. The future simulations show, that parts of the Antarctic ice sheet become unstable even under low-emission scenarios, with significant implications for the modelled climate response. Sensitivity experiments additionally show that, the Greenland ice sheet may exhibit multiple steady-states under pre-industrial climate conditions. This has significant implications for a potential regrowth, once disintegrated entirely.
- Speaker: Marie-Luise Kapsch (Max Planck Institute for Meteorology)
- Wednesday 12 February 2025, 17:30-19:00
- Venue: Latimer Room, Clare College.
- Series: Quaternary Discussion Group (QDG); organiser: wb350.
Wed 19 Mar 17:30: Rise and fall of Bronze Age Mediterranean societies: a new geoarchaeological and chronostratigraphic sequence of Nuragic Sardinia
Around the beginning of the Late Holocene (4,200 years BP) across the western Mediterranean regions, Bronze Age societies developed unique socio-economic and political complexity reflected in the construction of monumental stone architecture. New geoarchaeological and chronostratigraphic research in Sardinia, Italy, exposes for the first time the environmental underpinnings of the expansion and decline of the Nuragic Bronze Age monument-building society. These findings also highlight the role of prehistoric societies in shaping the landscape of the Mediterranean region over the Holocene. Multi-proxy geoarchaeological analyses—including soil micromorphology, XRD mineralogy, magnetic susceptibility, and geochemistry—reveal that the Bronze Age climax soil type of basaltic mesas in Sardinia was a dark Vertisol rich in primary nutrients and montmorillonite clay. These fertile soils sustained grassland ecosystems and played a key role in the distribution of early Middle Bronze Age Nuragic monuments across Sardinia’s basaltic landscapes. However, prolonged and intensified land use, particularly animal herding and agriculture, to support monument construction led to soil erosion and, ultimately, the replacement of deep, nutrient-rich Vertisol cover with a thin, oxidised and vertic Cambisol one. These processes resulted in a significant increase in sediment supply in the catchment east of the mesa, causing a new major phase of alluviation in the valley bottoms during the Late Holocene. These landscape changes triggered a socio-environmental crisis marked by the abandonment of the mesa at the end of the Middle Bronze Age, hence excluding the influence of a climate change in causing the local societal collapse.
- Speaker: Gian Battista Marras (British School at Rome)
- Wednesday 19 March 2025, 17:30-19:00
- Venue: Latimer Room, Clare College.
- Series: Quaternary Discussion Group (QDG); organiser: sr632.
Wed 19 Mar 17:30: Rise and fall of Bronze Age Mediterranean societies: a new geoarchaeological and chronostratigraphic sequence of Nuragic Sardinia
Around the beginning of the Late Holocene (4,200 years BP) across the western Mediterranean regions, Bronze Age societies developed unique socio-economic and political complexity reflected in the construction of monumental stone architecture. New geoarchaeological and chronostratigraphic research in Sardinia, Italy, exposes for the first time the environmental underpinnings of the expansion and decline of the Nuragic Bronze Age monument-building society. These findings also highlight the role of prehistoric societies in shaping the landscape of the Mediterranean region over the Holocene. Multi-proxy geoarchaeological analyses—including soil micromorphology, XRD mineralogy, magnetic susceptibility, and geochemistry—reveal that the Bronze Age climax soil type of basaltic mesas in Sardinia was a dark Vertisol rich in primary nutrients and montmorillonite clay. These fertile soils sustained grassland ecosystems and played a key role in the distribution of early Middle Bronze Age Nuragic monuments across Sardinia’s basaltic landscapes. However, prolonged and intensified land use, particularly animal herding and agriculture, to support monument construction led to soil erosion and, ultimately, the replacement of deep, nutrient-rich Vertisol cover with a thin, oxidised and vertic Cambisol one. These processes resulted in a significant increase in sediment supply in the catchment east of the mesa, causing a new major phase of alluviation in the valley bottoms during the Late Holocene. These landscape changes triggered a socio-environmental crisis marked by the abandonment of the mesa at the end of the Middle Bronze Age, hence excluding the influence of a climate change in causing the local societal collapse.
- Speaker: Gian Battista Marras (British School at Rome)
- Wednesday 19 March 2025, 17:30-19:00
- Venue: Latimer Room, Clare College.
- Series: Quaternary Discussion Group (QDG); organiser: sr632.
Wed 12 Feb 17:30: The impact of climate-ice sheet interactions on abrupt climate changes in the long-term past and their importance for the future climate
The simulation of the last deglaciation (about 20.000 years before present to present) represents a hitherto unsolved challenge for comprehensive state-of-the-art climate models. During my presentation, I will introduce our novel coupled atmosphere-ocean-vegetation-ice sheet-solid earth model that is used to simulate the transient climate. An ensemble of transient model simulations successfully captures the main features of the last deglaciation, as depicted by proxy estimates. In addition, our model simulates a series of abrupt climate changes, which can be attributed to different drivers that will be discussed throughout the presentation. I will furthermore show, how the model can be applied for simulations of the long-term future. The future simulations show, that parts of the Antarctic ice sheet become unstable even under low-emission scenarios, with significant implications for the modelled climate response. Sensitivity experiments additionally show that, the Greenland ice sheet may exhibit multiple steady-states under pre-industrial climate conditions. This has significant implications for a potential regrowth, once disintegrated entirely.
- Speaker: Marie-Luise Kapsch (Max Planck Institute for Meteorology)
- Wednesday 12 February 2025, 17:30-19:00
- Venue: Latimer Room, Clare College.
- Series: Quaternary Discussion Group (QDG); organiser: wb350.
Wed 19 Feb 17:30: Reconstructing levels of volcanism in the late Pleistocene
Volcanism is known to act as a driver of change to the Earth system on a range of scales. Degassing of greenhouse gases may act to drive global warming, whilst the weathering of fresh volcanic material may enhance the silicate weathering feedback and aid cooling of Earth’s climate. At the same time, the intensity of volcanism responds to other aspects of the Earth system. For example, low sea levels and low ice volumes may both act to increase levels of volcanic activity through the release of pressure on magma chambers. These interactions in turn may control the level of impact volcanism has as a driver of change. To fully understand the interaction between volcanic activity and climate, however, reliable records of changing volcanic intensity through time are required. Such records have been, to date, either regional or of low resolution. Here, I will discuss two approaches to this problem, firstly through the compilation of volcanic material occurrence in deep sea sediment cores. Secondly, I will present the application of inversion of atmospheric carbon dioxide records as an approach to reconstructing periods of imbalance and likely volcanic activity in the carbon cycle. Both approaches highlight a shift in the late Pleistocene at around 400 ka, whereby more volcanic activity is reconstructed, and the activity becomes cyclical in nature. This may be linked to Mid Brunhes Transition, a period of strengthening in amplitude of glacial-interglacial cycles, and indicates how Earth system changes may impact volcanic intensity.
- Speaker: Jack Longman (Northumbria University)
- Wednesday 19 February 2025, 17:30-19:00
- Venue: Latimer Room, Clare College.
- Series: Quaternary Discussion Group (QDG); organiser: wb350.
Wed 12 Feb 17:30: The impact of climate-ice sheet interactions on abrupt climate changes in the long-term past and their importance for the future climate
The simulation of the last deglaciation (about 20.000 years before present to present) represents a hitherto unsolved challenge for comprehensive state-of-the-art climate models. During my presentation, I will introduce our novel coupled atmosphere-ocean-vegetation-ice sheet-solid earth model that is used to simulate the transient climate. An ensemble of transient model simulations successfully captures the main features of the last deglaciation, as depicted by proxy estimates. In addition, our model simulates a series of abrupt climate changes, which can be attributed to different drivers that will be discussed throughout the presentation. I will furthermore show, how the model can be applied for simulations of the long-term future. The future simulations show, that parts of the Antarctic ice sheet become unstable even under low-emission scenarios, with significant implications for the modelled climate response. Sensitivity experiments additionally show that, the Greenland ice sheet may exhibit multiple steady-states under pre-industrial climate conditions. This has significant implications for a potential regrowth, once disintegrated entirely.
- Speaker: Marie-Luise Kapsch (Max Planck Institute for Meteorology)
- Wednesday 12 February 2025, 17:30-19:00
- Venue: Latimer Room, Clare College.
- Series: Quaternary Discussion Group (QDG); organiser: wb350.
Wed 05 Mar 17:30: Breaking the Ice: Abrupt climate change and deglaciation
The past glacial period and ensuing deglaciation were punctuated by multiple episodes of abrupt climate change. Despite decades of research, the causes of the rapid changes remain largely unknown, and, crucially, they are very difficult to reproduce with Earth System Models. In this seminar, I will present a series of recent and brand new climate model experiments for the last deglaciation, exploring the climate-ice-ocean interactions that trigger major abrupt changes in, for example, ocean circulation, surface temperature, ice volume and sea level. I will conclude the presentation with some of our work-in-progress using uncertainty quantification to produce the best and most rigorous models of climate change.
- Speaker: Ruza Ivanovic (University of Leeds)
- Wednesday 05 March 2025, 17:30-19:00
- Venue: Latimer Room, Clare College.
- Series: Quaternary Discussion Group (QDG); organiser: sr632.