Emerging pests and pathogens (EPPs) are an increasingly disruptive force to human society that can cause large social and ecological changes far beyond their initial site of emergence. Three forces contribute to this growing challenge now and in the foreseeable future: first, potential EPPs are more likely to come in to first contact with human habitats as human land use expands. Second, denser human trade and travel networks mean that EPPs are more likely to emerge in new regions. Third, human technology, such as biocidal agents, increases risks for re-emergence. Understanding how EPPs cascade across scales in social-ecological systems is therefore an urgent priority, but no formal approach currently exists for analysing the ripple effects at scale, from their seeding to their lasting societal imprints. This project aims to fill this gap in sustainability science for society. The INFLUX project will test the hypothesis that EPPs commonly cascade to interact with large-scale social and environmental challenges and that small differences in social-ecological conditions in turn influence the likelihood and nature of EPP cascades. I will test this hypothesis by leveraging a comparative, mixed-methods research design to assemble a large database for up to 1600 EPPs, encompassing microbial pathogens as well as arthropod and plant pests. Specifically, four objectives will be pursued, which are to understand: 1. The drivers of emergence risk and their connections to human environmental sustainability and social conditions. 2. The types of cascades that result from action aimed at governing EPPs. 3. The lasting impacts EPPs have on societies and the conditions under which they arise. 4. The feedbacks from 3.-1. including through implications for social equity and environmental sustainability. INFLUX constitutes a major step in situating EPPs in the field of sustainability science, and for developing societal capacity to navigate a future characterized by them

Concentrations of greenhouse gases are rising as a result of continued industrial activity with consequences for our future climate. The biosphere has been suggested as a significant factor mitigating atmospheric change, through its capacity to respond to this change by sequestering additional carbon. Key to our understanding and evaluation of these processes is knowledge about the extent to which ecosystems acclimate to elevated CO2. Some research has indicated only short-term growth responses to elevated CO2, but these studies have often focussed on production responses ignoring more subtle shifts in whole ecosystem function. Even where acclimation has occurred, it is important to determine whether any new state of equilibrium results in altered ecosystem function, especially with regard to C loss or gain. Arctic ecosystems are of critical importance to global conservation and store up to one-third of global soil carbon reserves. Their stability under future atmospheric CO2 scenarios will have major influences on global biodiversity and warming. In this study we want to test whether arctic plant communities do not acclimate fully even with extended exposure to elevated CO2, that below-ground responses lag those above-ground and that exposure to elevated CO2 has a cumulative effect on ecosystem properties that influence ecosystem stability, resistance and resilience. As a result of anthropogenic gaseous emissions, the climate of Arctic regions is likely to alter, in particular with regard to temperature and precipitation. These changes, and other periodic perturbations will challenge the stability of current vegetation and soil microbial processes. Sub-arctic heath systems are also subject to periodic mass herbivory events, for example due to mass infestation by the moth Epirrita autumnata. We will therefore investigate field responses (leaf regrowth and soil respiration) to a simulated defoliation event. In a controlled environment facility, we will also investigate whether variations in soil temperature and moisture content will interact with the future capacity of Arctic soils to retain sequestered C under future elevated CO2. The information from this research programme is vital if we are to be able to make effective management decisions based on improved predictions from climate models. Specifically, the extent to which whole ecosystems acclimate to elevated CO2 is a key area of uncertainty in predicting and modelling future scenarios. Research findings will also significantly advance our understanding of the stability of Arctic ecosystems to perturbations under future climate change and important potential impacts on global biodiversity impacts.