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Pesticide use is a crucial human-driven change in the Anthropocene that negatively impacts the environment and ecosystems. While pesticides are essential to agriculture to sustain crop production and ensure global food security, they also lead to significant environmental impacts. The export of pesticides after application from the agricultural fields threatens the soil, groundwater and surface water quality in many world regions. Pesticide use is constantly increasing globally, driven mainly by agricultural intensification, despite stricter regulations and higher pesticide effectiveness. To enhance the understanding of future pesticide use and emissions and make informed farm-to-policy decisions, we developed Pesticide Agricultural Shared Socio-Economic Pathways (Pest-Agri-SSPs) in six steps. The Pest-Agri-SSPs are based on an extensive literature review and expert knowledge, considering significant climate and socio-economic drivers from farm to continental scale in combination with multiple actors impacting them. In the literature, pesticide use is associated with farmer behaviour and agricultural practices, pest damage, technique and efficiency of pesticide application, agricultural policy and demand for agricultural products. Here, we developed Pest-Agri-SSPs upon this understanding of pesticide use drivers and relating them to plausible sectoral developments, as described by the Shared Socio-economic Pathways for European agriculture and food systems (Eur-Agri-SSPs). The Pest-Agri-SSPs present European pesticide use in five scenarios with low to high challenges to climate change adaptation and mitigation up to 2050. The most sustainable scenario (Pest-Agri-SSP1) shows a decrease in pesticide use owing to sustainable agricultural practices, technological advances and a pro-environmental orientation of agricultural policies. On the contrary, the Pest-Agri-SSP3 and Pest-Agri-SSP4 show an increase in pesticide use resulting from high challenges from pest pressure, resource depletion and relaxed agricultural policies. Pest-Agri-SSP2 presents a stabilised pesticide use resulting from strict policies and slow transitions by farmers to sustainable agricultural practices. Pest-Agri-SSP5 shows a decrease in pesticide use for most drivers, influenced mainly by rapid technological development and the application of sustainable agricultural practices. However, Pest-Agri-SSP5 also shows a relatively low rise in pesticide use driven by agricultural demand, production, and climate change. Our results highlight the need for a holistic approach to tackle pesticide use and emissions, considering the identified drivers and future developments. The storylines and qualitative assessment provide a platform to make quantitative assumptions for numerical modelling and evaluating policy targets. Keywords: Farm characteristics, pest damage, technology, policy, socioeconomic, agriculture and food systems Adapted version of this work has been submitted to Journal of Environmental Management: Nagesh P, Edelenbosch OY , Dekker SC, de Boer HJ, Mitter H, van Vuuren DP. Pesticide use under the influence of socio-economic and climate change: Pest-Agri-SSPs

Agricultural use of pesticides helps control a range of pests and diseases that threaten crops, thereby avoiding yield losses and improving the quality of the food produced. However, pesticides applied on agricultural fields dissipate with time. The export of pesticides and their transformation products after application from the agricultural fields threatens the water quality of aquatic systems in many world regions.Climate change is further expected to intensify pest pressures and potential pesticide use by affecting agriculture in many ways. Changing climatic conditions can increase pesticide leaching due to increased and frequent rainfall, higher degradation rates, or higher temperatures or soil moisture contents. The indirect effects are changes in land use, the timing of crop cultivation, selection of other crop types, new pests and changed pest behaviour, etc. Additionally, several socio-economic factors influence pesticide use at the farm and national level, including regulation and legislation, economy, technology and crop characteristics. In order to better understand the pesticide risk to surface waters in the future, we aim to understand the influence of both climate and socio-economic change on pesticide use and fate.Various catchment-scale models are available to assess pesticides and their impacts on water bodies. However, most modelling approaches solely concentrate on the total amount or concentration of pesticide exported from a catchment and do not necessarily analyse the future change of pesticide and transformation products. We propose an integrated modelling framework to answer the research questions: What are the current significant climate and socio-economic drivers influencing pesticide use and emissions? How can climate change influence pesticide and transformation products emission trends? How will socio-economic change influence pesticide emissions?The integrated modelling framework helps to include adapting agricultural production to climatic (e.g., temperature, precipitation) and socio-economic drivers (e.g., land use, crop type, pesticide regulation) and quantifying pesticide emissions with the Zin-AgriTRA pesticide fate model. The ZIN-AgriTra is a catchment scale reactive transport model which can simulate agrochemical and transformation products exported from agricultural catchments. We use the Eur-Agri-SSP scenarios that extend and enrich the basic Shared Socio-economic Pathways with a regional and sectoral component on agriculture to explain the socio-economic change and climate projections for Representative concentration pathways to adopt climate change scenarios.The integrated modelling framework links the future scenario results from independent, standalone models that present crop rotation, land use, pesticide regulation and climate to the pesticide fate model (Zin-AgriTRA). The framework is applied to an agricultural catchment in Burgenland, Austria, to quantify pesticide pollution under future climate and socio-economic change up to 2050.

Water is an essential resource for human life and the environment. The widespread use of chemicals in daily life has led to significant water quality concerns. During the production phase, the use phase as well as after use, (residues of) these chemicals can enter the environment and water systems. Furthermore, the use and production of chemicals are increasing rapidly, driven by mainly population growth, urbanisation and economic growth. Increased use leads to further emissions of chemicals to water, posing significant water quality concerns. Henceforth there is an urgent need to understand the linkage between society and production and consumption of chemicals to explore possible changes in water quality.Socio-economic scenario analysis is a useful tool to investigate the long-term consequences of future change and mitigation options. While scenarios have been broadly applied to understand air pollution, this not yet the case for chemical pollution to surface waters. In this work, we propose a general framework to develop scenarios for the future emissions of chemicals to water by using the Shared Socio-economic Pathways (SSP). The framework follows the basic elements of the scenario development process by defining the current system, describe the changes in emissions with scenario drivers and elaboration to the future. The framework is then tested on a set of selected ‘example’ chemicals that represent broader chemical groups of pharmaceuticals (Ibuprofen and Diclofenac), pesticides (Terbuthylazine) and industrial chemicals (Cadmium and Di-ethyl phthalate). Chemical emissions to water over the past years were used to understand their yearly trends and patterns over the European countries. Lastly, the emission scenarios for chemicals for 2050 were developed by using SSP drivers from the IMAGE Integrated assessment model as an input to the empirical emission models. The three SSP scenarios: SSP1 ("Sustainability"), SSP2 ("Middle of the Road") and SSP3 ("Regional Rivalry") focusing on Europe were included. Additionally, the developed scenarios also describe mitigation efforts.The results of emission scenarios displayed an increase in emissions up to 2050 for the exemplary chemicals in Western Europe for all three scenarios SSP1, SSP2 and SSP3. While the emissions of chemicals linearly decreased in Eastern Europe for the same period. SSP3 showed the highest emissions in 2050 except for cadmium emissions from wastewater treatment plants. The results showed that the framework helps in understanding the possible influence of socio-economic changes on use and emissions of chemicals which can be a part of future risk assessments. While the framework can be extended similarly to other pharmaceuticals and pesticides, it requires a detailed understanding of complex emission sources for industrial chemicals.