The intense precipitation associated with large storms can initiate thousands of landslides and debris flows, endangering lives and cause significant damage to infrastructure. Changes to the frequency and/or intensity of storms is a predicted consequence of anthropogenically-driven climate change (Rosenzweig et al., 2007), thus predictive models of landsliding are essential for mitigating these effects. Shallow landslides that initiate in soil are particularly destructive as they often initiate rapidly moving debris flows. Physically-based shallow landslide hazard models usually estimate landsliding a function of modern hydrologic, ecologic, and soil mechanical properties (Montgomery and Dietrich, 1994; Pack et al., 2001). The flaw in this approach is that it does not account for the "memory" of previous landslides in a catchment, where landslides are unlikely to occur twice in the same location within the short window of time (<1000 years). When landslide "memory" is considered, we hypothesise two possible effects on future landsliding: (1) the likelihood that extreme rainfall will create a large landslide event is dependent on the number of large storms that have recently occurred in a catchment, and (2) storms that initiate a 1000's of landslides may have a resonance within a landscape that causes landslides to cluster in time. Accounting for the combined role of precipitation and landscape resonance is of immediate concern as we begin to make predict hazards associated with climate change. The proposed research will quantify whether landslides are clustered in time, through the collection of a novel, large, millennial-scale dataset of landslide frequency. We will analyse landslide frequency using radiocarbon found at the base of 75 hollows (local depocentres located 10's of metres above channel heads) where shallow landslides initiate. These data, in conjunction with high resolution LiDAR topographic data, will drive the creation of a unique, probabilistic, landslide hazard model that estimates landslide hazard based on both recent precipitation and the potential resonance imparted by previous storms. Our novel landslide dataset and landslide hazard model will significantly improve our ability to predict the risks posed by landslides in current and future climate scenarios.

Millennial-scale climate variability in the subpolar North Atlantic is thought to be a pervasive, common feature of marine, ice core and terrestrial archives throughout the Holocene, mainly driven by changes in the Atlantic Meridional Overturning Circulation (AMOC). Strong ocean-atmosphere coupling in the North Atlantic mean that stronger (or weaker) westerlies associated with a prolonged positive (or negative) North Atlantic Oscillation (NAO) phase may have enhanced AMOC during the last millennium. We intend to demonstrate for the first time that the proposed atmospheric forcing of AMOC during the past millennium is an underlying mechanism that persists throughout the Holocene. AMOC variability plays an important role in the modulation of European (and global) climate variability through the latitudinal transfer of heat northwards via the North Atlantic Current (NAC) and there is an emerging understanding of the importance of subpolar gyre (SPG) dynamics, primarily driven by atmospheric forcing, upon the salinity of the NAC and hence the strength of AMOC. The fjordic environments of Scotland, as represented by Loch Sunart, are well-placed to capture this variability, and together with recent tephrochronological advances at this site, present a unique opportunity to underpin the chronology of regional land-ocean interactions during the Holocene. High-resolution (0.3 cm/yr) reconstructions of salinity, temperature and circulation from a 22.5m long core (MD04-2832), recovered from Loch Sunart (NW Scotland), reflect the controls of both NE Atlantic hydrology and large-scale atmospheric forcing. For example, between 5-6 kyr, MD04-2832 proxies respond to a major reorganization in atmospheric circulation4, SPG dynamics and AMOC variability. The available chronological control in these records, however, limits our ability to critically test the relative timing of these large-scale northern hemisphere synoptic climate changes. The aim of this proposal is to establish a tephra stratigraphy for MD04-2832, to underpin the precise timing of these large-scale shifts in Holocene marine climate and facilitate a comparison with proxies of atmospheric circulation recorded in Greenland ice cores and elsewhere. If the current understanding of stronger westerlies associated with a prolonged positive NAO phase linked to enhanced AMOC via SPG dynamics is correct, then we hypothesize that our marine proxy records from the west of Scotland will synchronize with large-scale changes in atmospheric circulation inferred from Greenland ice cores. Critically, given the uncertainties of existing age-control, tephra isochrones are the key to solving this chronological problem and a significant number of Holocene tephra are known from terrestrial settings in Scotland and Ireland.

The Antarctic continent is an important part of the Earth system, both influencing and responding to global ocean and atmospheric circulation. The ice sheet plays a major role in sea-level change and currently holds the equivalent of 70m of global sea-level rise. Monitoring change in the climate, cryosphere and biosphere of Antarctica is therefore a critical element in understanding and predicting future global change. Over the past 50 years, the climate over most of Antarctica has remained relatively stable, but the Antarctic Peninsula has experienced one of the highest rates of warming anywhere on Earth, with increases of 3oC since the 1950s, and even higher rates for winter in some locations. The rapid increase in temperature has been associated with decreased sea-ice extent, ice-shelf collapse, glacier retreat and increased ice flow rates, and changes in ecosystems on land and sea. However, the causes and context of the recent temperature changes are unclear, although it is thought that stratospheric ozone depletion and increasing greenhouse gases are both important. Current global climate models do not capture the observed changes adequately at present. A key question in understanding and attribution of Antarctic climate change is whether the recorded changes on the Peninsula are unusual compared with past natural climate variability. However, this question cannot be addressed because the instrumental records are too short and existing proxy-climate records are not suitably located to be able to trace the spatial signature of change over time. The project proposed here will exploit moss banks as a new proxy-climate archive to test three key hypotheses: 1) The recent temperature rise on the Antarctic Peninsula is unprecedented in the late Holocene. 2) The spatial pattern of variability is similar to that which occurred during previous periods of climate change. 3) Plant communities are responding to recent climate change by increases in growth rates and altered seasonal growth patterns. Moss banks are ideal deposits for reconstructing climate change over the land surface of the Antarctic Peninsula because of their location in relation to recorded temperature changes, their age, and their attributes as archives. The moss banks have accumulated peat over the past 5-6000 years at locations throughout the western Antarctic Peninsula. They are formed of only one or two species, annual growth can be traced in the surface peats and preservation of moss remains is good. We will use multi-proxy indicators of past climate (stable isotopes, measures of decay, testate amoebae and moss morphology) to reconstruct climate variability from critical locations across the observed gradient in rate of temperature change between 69o and 61o S. Although these techniques are tried and tested in more temperate regions of the world, they have not been employed in the Antarctic. We carried out pilot studies on Signy Island which show that these proxies work well for the moss banks in the Antarctic so we know that our approach will produce valuable results. Our work will also involve improving our understanding of proxy-climate relationships by a programme of surface sampling and measurement. The records will be calibrated using annually resolved records covering the period of instrumental observations. Together with records from Signy Island being produced as part of a current BAS PhD project supervised by members of the research team, emerging results from the BAS ice core at James Ross Island and some of the higher resolution ocean sediment records, our data will also provide the basis for a more complete understanding of late Holocene climate variability in the broader region, building on the BAS Past climate and Chemistry programme directed at reconstructing and understanding Holocene climate variability in the Antarctic Peninsula.

Sea-level change is one of the most significant threats facing society over the next 100 years and beyond. Measurements of current sea-level change have shown that there has been a mean global sea-level rise of between 10 and 20 cm over the 20th century. A further rise in sea level of between 20 and 80 cm is predicted by AD 2100 due to future global climate change. However, such predictions of future change are subject to very large uncertainties because our understanding of the past behaviour of sea level is poor. It is essential that we quantify sea-level changes in the recent past if we are to provide more accurate and precise predictions for the future. It is clear from measurements and from sea-level reconstructions based on geological data that there has been a significant increase in the rate of sea-level rise from the 19th to the 20th century. We ask the question: Have similar accelerations of sea-level rise happened in the past? Some of our published geological reconstructions give us good reason to believe that there were pre-industrial sea-level accelerations and these require further investigation. We aim to establish the precise timing and magnitude of these rapid rises of sea level by constructing detailed 500-yr histories of sea-level changes in six sites around the North Atlantic Ocean. These records will be based on the remains of fossil plants and animals buried in coastal sediments which are excellent indicators of the past level of the sea. Timing is key, so we will use the most advanced dating methods, in particular ultra-high precision radiocarbon dating techniques, to find out when the rapid increases in sea-level rise occurred. If the changes we observe occurred in various sites at the same time, then it would imply that hitherto unknown episodes of land-based polar ice melt are responsible. There are important processes that obscure the sea-level signal derived from melting ice that may be observed in coastal sediments and tide gauges. These include changes in the density of sea water - leading to expansion/contraction - due to temperature and salinity variations and vertical movements of the coast. We will correct for these processes separately, using models and available tide-gauge and ocean temperature measurements. First, we will create a model that can calculate steric (density) changes along the coast. Measurements of ocean density are available for the past 50 years, but these were taken in the open ocean, not near the coast. Many processes operating on the continental shelves, such as tides, currents and winds, mix the water column in these areas and so using ocean records may be inaccurate. Our model will help us to predict how the water density changes at the coast following a measured change in the middle of the ocean. A second model can simulate ocean steric changes for the past 500 years, a period for which ocean density and temperature data are not available. Some additional corrections for wind, air pressure and tidal changes, are also necessary but these are relatively easy to do. Second, we need to remove the effects of long-term land movements from our records. We will do this by reconstructing sea-level trends over the last 2000-3000 years and subtracting these from the proxy reconstructions. There are also geophysical models and GPS data that can help with this correction. The 'corrected' records of sea level will be analysed to determine whether synchronous episodes of sea-level rise have occurred in the past 500 years. We believe the work is important because it will, for the first time, enable us to test whether accelerations in sea-level in the North Atlantic have occurred at the same time or not, and if they have, we can determine how big they were. These data will provide important 'baseline' constraints for future sea-level predictions.

Does mountain building influence the global carbon cycle and carbon dioxide (CO2) concentrations in the atmosphere, and hence modify Earth's climate? This question is at the heart of a long-standing debate as to how erosion and weathering act to draw down CO2, countering the input of CO2 from volcanoes over millions of years. Earthquakes offer a direct way of removing CO2 from the atmosphere, but how this happens and how large the impact might be has remained poorly understood. Ground shaking during earthquakes can trigger tens of thousands of landslides, which strip large amounts of carbon from soil and plants in mountain forests. Depending on the amount of carbon involved, and what happens to it, earthquakes could be a way in which mountain building drives the global carbon cycle. If the carbon removed from mountain forests reaches rivers, it can be transported in muddy waters downstream and into a long-term sink (storage) of CO2 following burial in sediments. Our research aims to quantify, for the first time, whether large earthquakes could increase the erosion and river export of carbon from mountain forests. Until now, it has proved very challenging to measure the impact of these extreme and unpredictable events in river systems. This is because we need samples collected from rivers before and after earthquakes, in order to use geochemical measurements to fingerprint the carbon source and measure the carbon flux. The research team has recently been involved in the only case where this has been done, after the 2008 Wenchuan earthquake in China which triggered over fifty thousand landslides. There, we found that the carbon flux in a mountain river increased significantly in the four years which followed the earthquake and the associated catastrophic landsliding. Our work from Wenchuan sets the foundation for this research proposal, demonstrating that carbon mobilised by earthquake landslides does reach rivers. However, we expect the impacts to last for ten years, or even hundreds, and Wenchuan is just a single example. It is clear we need other data, and a new approach in order to fill this research gap. We will study multiple large earthquakes, and make measurements over decades to centuries before and after each earthquake. To do this, we will combine landslide maps from historical earthquakes around the world, with some of the best studied records of sediment export following large earthquakes in lakes. The well-dated and well-understood lake sediment records come from the western Southern Alps, New Zealand. They record the response of the mountain landscape to four large earthquakes over a thousand years. We will use geochemistry techniques to fingerprint and track the carbon sourced from vegetation and soil (rather than eroded from bedrock) and combine these with measurements of sediment flux to calculate carbon flux. This can be done for four earthquakes in two lakes, as well as during the 'background' periods before and long after the catastrophic landsliding. The datasets will allow us to confidently quantify how earthquakes increase carbon export from forests from a 'background' state. We will use the new data and our understanding of the main processes operating to build a model to allow us to assess the role of earthquakes for carbon flux in mountains on longer timescales. For the first time, we will be able to apply the model around the world to mountains which experience earthquakes. We will account for changing earthquake size and how often they happen, and the amount of carbon in the forest and the rate at which it is degraded in landslide deposits. We will also consider how different rainfall patterns in river catchments can change the flux of carbon. With these novel insights, we will be able to quantify how earthquakes impact the carbon cycle, CO2 and the evolution of Earth's climate.