Global climate change is one of the big challenges society faces today. Warming of the climate system is unequivocal, and evident from observations of increasing global average temperatures. Warming is also observed in the oceans, and is accompanied by a change in salinity, with the high latitudes becoming 'fresher' (i.e., less saline) and the subtropics and tropics becoming more saline - a redistribution of properties that has the potential to affect ocean circulation. There are also clear effects of climate change on the chemistry of the oceans. Whilst increased uptake of more abundant atmospheric carbon dioxide leads to an acidification of the oceans that threatens marine ecosystems, only little is known about the effects of higher concentrations of certain trace metals, as a result of anthropogenic pollution and changing erosion patterns on land. Such changes are very important, however, as the ability of the ocean to take up carbon dioxide from the atmosphere is strongly coupled to the supply of so-called nutrients, elements that are essential for life in the ocean. As part of this project, we will develop a better understanding of such 'biogeochemical cycles'. We picked out three trace metals, neodymium (Nd), cadmium (Cd), and lead (Pb), which together represent the behaviour of many different elements in the ocean. For example, both Cd and Pb are today supplied to the environment by human activity and this may alter their natural cycles. As Cd is an important micronutrient in the ocean, such changes could also affect the global carbon cycle. As part of our project, a PhD student will focus on understanding whether the natural flux of dust from desert areas to the ocean and the anthropogenic particles the dust scavenges in the atmosphere have an important impact on the marine Cd and Pb cycles. The student will furthermore study, how the cycling of these elements in the ocean is altered by changing oxygen concentrations. Oxygen is (next to the nutrients) another important player in biogeochemical cycles, and its solubility in seawater is temperature dependent. Climate models predict that extended zones with low oxygen concentrations will develop in the future oceans. Another important aspect of the ocean system is that ocean currents are the key mechanism for distributing heat, and thus they have a significant impact on regional and local climate. Furthermore, water mass movements (both vertical and lateral) are very important for the carbon cycle, as the deep ocean contains 50-60 times more carbon than the atmosphere. Today we can monitor ocean circulation by measuring the physical properties of seawater. Observations over the past 50 years, however, do not give us any clear indication whether the pattern of ocean circulation is changing. From studies of the past we know, however, that ocean water masses had a different configuration during the ice ages and past periods of extreme warmth. Neodymium isotopes in seawater are often used for such reconstructions, and the results show stunning relationships between past temperatures, carbon dioxide levels, and ocean circulation. A patchy understanding the modern Nd cycle however limits our confidence in such reconstructions, and thus our ability to transfer the inferred mechanisms to future models. In particular, it is generally assumed that away from ocean margins, Nd isotopes are an ideal ocean circulation tracer as they are only modified by mixing between water masses. However, there are many potential marine processes, which may not be in accord with this simplistic view. Such uncertainties will be addressed by the current project, based on a comprehensive suite of new observational data that will be collected for samples from strategic locations in the Atlantic Ocean. In conjunction with modelling efforts, our new data will shed light on the processes governing the marine Nd cycle and the suitability of Nd isotopes as circulation tracer.

The COVID-19 pandemic is having substantial consequences on UK and global food and nutrition security (FNS). This project will undertake world-leading research to provide government, business and decision makers with the evidence that they need to develop a robust FNS response to the current pandemic. The pandemic is causing major shocks to the four pillars of FNS: access; availability; utilisation and stability. Examples include reductions in productivity (labour limitations), breakdown of norms of food systems (distribution, changed demand) and supply chain restrictions (e.g. shortages of agri-chemicals for crop management). Economic impacts are altering both supply, distribution and demand. Collectively these shocks are substantially altering food systems whilst in the longer-term normal processes of trade may not adapt appropriately leading to changes in the balance of traded commodities, reduction in food reserves and price increases. The issue of FNS is relevant to all members of society, particularly for those most vulnerable to shortages or price increases. The food sector is also a major part of the UK economy, as it contributes approximately £111 billion a year and accounts for over 13% of national employment. It is the UK's largest manufacturing sector. The project focusses on UK FNS which is heavily dependent on global markets. Nearly half of the food we consume is imported and UK livestock industries rely heavily on imported feed. Some countries have already restricted exports in order to supply home markets. Normal market forces, transportation and distribution networks may no longer be appropriate to provide national requirements. A priority is to understand how to increase capacity for self-reliance to maintain civic stability, a healthy population and to understand the ramifications for third countries. The aim of this study is to conduct an initial rapid FNS risk assessment and explore options for changes in agricultural production, trade and distribution to protect FNS without jeopardising wider ecological and climate goals. The Research Programme will deliver seven key outputs: 1. Report on rapid risk assessment of the global food system considering how direct and indirect COVID-19 impacts and responses are propagating risks to food and nutrition security. 2. Report on Rapid risk assessment of UK food system responses and vulnerabilities and consequences on access, availability, utilisation and stability. 3. A set of plausible scenarios to explore the cascading risks and consequences of pandemic impacts on food sand nutrition security. 4. Report on alternative land use and management options that will increase resilience. 5. Report and maps of the spatial assessment of the alternative land use and management options. 6. Report including infographics reviewing lessons learned from the pandemic to improve Food and Nutrition Security. 7. Two workshops and other dissemination events and report with recommendations. The knowledge and foresight generated will be applicable to and of value across multiple sectors of the economy. It will inform policy support and development within UK and devolved Governments and help industry and business make informed decisions and plan adaptations. Information generated will support the UK's strong position in global trade. Identifying data gaps now will enable improved monitoring of impacts, both at UK and global scales.

In Asia and West Africa the majority of rain falls during the summer monsoon season. Monsoon rain is vital for agriculture, and a late or weak monsoon can mean disaster for crops, to the point where the Indian finance minister once described the monsoon as the country's 'real finance minister'. However, while we have a strong conceptual understanding of climatic changes controlled by thermodynamics (e.g. temperature, sea level), changes controlled by wind patterns (e.g. regional precipitation) are far less intuitive. State-of-the-art models struggle to correctly simulate patterns of monsoon rainfall in the present day, and predict a range of future changes. Without basic understanding of the wind circulations controlling the monsoons it is impossible to judge which predictions we can trust, both seasonally and under global warming. Recently, major advances have been made in our understanding of the mechanisms controlling the monsoons by using very abstract model configurations: aquaplanets (planets covered only in water) and simulations including simple continents. By stripping back the complexity of the real world, these models have at last given us basic theories for the controls on when and where zonal-mean tropical rain falls. However, these successful theories have in general not yet been adapted to the regional scale, and this presents an enormous opportunity for a step-change in our fundamental understanding of regional monsoons, their variability and response to climate change. To address the challenge of connecting theory to reality, we have identified a novel approach combining machine learning methods with a hierarchy of model simulations and data. The model hierarchy will allow us to study how monsoon circulations behave and theory performs as complexity increases. In particular, we will make use of a new, highly-configurable idealised climate model, Isca, which allows us to run simulations ranging from very simple aquaplanets up to a simplified model of Earth within a single, consistent framework. A major challenge in understanding regional monsoons is that the mathematics underpinning theory becomes highly complex at a local scale. However, machine learning has recently been applied to similar problems in oceanic science to identify regions governed by different key processes. We will use these techniques to simplify the mathematics and develop regional theories for monsoon rainfall. Theories appropriate to each region will be used to interpret the behaviour of the latest state-of-the-art climate models. We will use both simulations of past and future climate, and more idealised simulations targeted at identifying differences between models in simulating processes contributing to climate change (e.g. sea ice, plant physiology). This should help in understanding biases in simulations of historical climate and constraining intermodel differences in projections of climate under global warming. By identifying which models can be trusted to simulate the monsoons and the drivers of future changes, it should be possible to produce more robust and useable projections for these key regions. The final phase of the project will test whether different theories are needed to understand monsoon behaviour on different timescales. Do theories for climatological rainfall also explain rainfall variations week-to-week, or decade-to-decade? Do these processes have a lead time which could provide information for subseasonal-to-seasonal or decadal forecasting? Can theoretical insight help us untangle how decadal variations in sea surface temperature modulate the processes governing interannual variability in monsoon rain? By approaching these complex problems from a new perspective, Bridge aims to at last build the same level of confidence in our predictions of circulation-governed monsoon rainfall as we have in thermodynamically controlled climate features.

The Hawaiian-Emperor Seamount Chain is arguably the world's best known example of hotspot magmatism, where volcanic activity and earthquakes occur far from plate boundaries. Nevertheless, questions remain about the fundamental processes that control such magmatism and seismicity along the 5800-km-long, 0-80 Ma, chain, in part because the volume and compositions of frozen magma that has been added to the surface and base of Pacific oceanic crust is too poorly known. The aim of this study is to use 'state of the art' marine seismic imaging techniques to constrain the thickness and composition of the magmatic material created by the Hawaiian hotspot, how it varies along the seamount chain, and how the Pacific oceanic plate has deformed in response to volcano loading. This study, which is a collaborative one with US scientists at Lamont-Doherty Earth Observatory, will utilize reprocessed seismic reflection and refraction data acquired on previous research cruises (e.g. R/V Robert D. Conrad C2308, R/V Thomas Washington Roundabout 2, and R/V Maurice Ewing EW9801), together with a new data set that will be acquired onboard R/V Marcus G. Langseth during late summer, 2018 and early summer, 2019. The Langseth cruises, which have been funded by the National Science Foundation (Marine Geology and Geophysics Division), will acquire deep penetration seismic reflection data using a 15 km long streamer and a large tuned airgun array and wide-angle reflection/refraction data using 70 Ocean Bottom Seismometers spaced at 15 km intervals along four 500-km-long transects of the chain. The transect locations have been carefully chosen to represent variations in the timing of magma emplacement and volume flux, the age of oceanic lithosphere at the time of loading and the presence/absence of a mid-plate topographic swell, and are sufficiently long to capture the response of the lithosphere to volcano loading out to the flexural bulge. The reprocessed and processed seismic reflection profiles and velocity models created from wide-angle seismic data will constrain the volume and distribution of magmatic addition to the surface and base of the crust, the nature of the stratigraphic fill in the flanking flexural moats and the relative role of faulting within the flexed volcanic edifice and underlying oceanic plate. The seismic constraints will be integrated with swath bathymetry and potential field data, compared to other marine geophysical studies of hotspot magmatism and used as the basis for thermal and mechanical modeling in order to gain fundamental insights into crust and lithosphere rheology and stress state and to inform potential geohazards along the chain such as large-scale slope failures, fault slip and tsunamigenic earthquakes. The study proposed here is central to NERC's strategy especially as it involves discovery science that impacts on how planet Earth works, how it deforms in response to surface and sub-surface loads and how it might deform in the future.

It is estimated that 5% of the world's population lives on land which is less than 5 metres above current sea level, in communities that are vulnerable to the impacts of sea level rise, either from direct loss of land, or increased flood risk. Society more broadly may be impacted by disruption to key infrastructure which is located on the coast e.g. power stations, and by the movement of displaced communities. The Antarctic ice sheet is the largest potential contributor to future sea level rise and projections of Antarctic ice sheet change in the future also have the largest range of estimates. This makes it difficult to accurately determine the risks of future sea level rise. Because sea level rise from Antarctic ice loss is not evenly distributed across the oceans, retreat of the Antarctic Ice Sheet will disproportionately affect coastlines that are furthest away, such as those in Europe and North America. In this proposal we will improve projections of Antarctic ice sheet change by reconstructing how the ice sheet changed during past warm intervals during the mid-Pliocene (approximately 3 million years ago). The mid-Pliocene is the last geological interval when atmospheric CO2 was similar to present day. The proposal will focus on reconstructing the amplitudes of mid-Pliocene sea level change between colder glacial stages and warmer interglacial states. We will use these data as a constraint for two types of ice sheet models. Recent work has used Pliocene interglacial sea level maxima as a constraint for Antarctic ice sheet models and has led to much higher projections of future sea level rise from Antarctica under anthropogenic warming. However, subsequent work has suggested that it may not be possible to accurately determine absolute Pliocene sea level maxima, such that the value of using these data has been questioned. The main source of uncertainty on these estimates comes from attempts to quantify them relative to a modern-day reference (i.e. as metres above present). An alternative approach that we will propose and one that can greatly improve past sea level estimates is to focus on the Pliocene glacial-interglacial sea level amplitude. We will reconstruct the glacial-interglacial sea level amplitude for 3 intervals in the mid-Pliocene using analysis of sediments recovered from the drilling of ocean sediment cores. Specifically, we will measure the geochemical composition (the isotopes of oxygen, magnesium and calcium) of calcite microorganisms (benthic foraminifera) to reconstruct past ice volume. In the absence of a modern-day reference we will simulate both the Pliocene glacial (cooler climate intervals) and interglacial (warmer climate intervals) extent of the Antarctic and Northern Hemisphere Ice Sheets (principally the Greenland Ice Sheet) and compare this with the sea level data that we will produce. We will then be able to determine what was the magnitude of Antarctic ice sheet melt during the past. Combining two groups based in the UK and US, the ice sheet models used will include the Penn State Ice Sheet Model (PSU-ISM) and the BISICLES ice sheet model. The treatment of the grounding line physics (the point at which grounded ice becomes floating ice shelf) is very different in these two models. The PSU-ISM requires additional processes (ice shelf hydrofracture and ice cliff failure) to simulate Antarctic retreat that was consistent with Pliocene sea level maxima. By using the BISICLES model, which has much higher resolution at the grounding line, we will be able to test whether these processes are needed to simulate ice retreat consistent with our measured Pliocene sea level amplitudes. Finally, we will use what we learn to produce a new set of future sea level estimates that are constrained using the palaeoclimate data. These will have tighter constraints than previous future sea level projections, enabling a more accurate estimate of the risk of future sea level rise from Antarctica.