3.2.1 Summary feedback “authorities”:
From most MS no feedback was received. Most authorities which provided feedback acknowledged the importance of the topic. However, there are often no activities regarding climate change adaptation of the registration process of PPP on authority level ongoing. It appears that often this is due to limited capacities and consequently a backlog of planned activities from recent years, or a higher prioritisation of other topics such as integrated pest management or application via drones.
However, from some authorities additional feedback has been received highlighting further activities on the topic.
The Umweltbundesamt (UBA) in Germany stated that in the past a research project was initiated to evaluate the potential impact of climate change on PPP use. It was focused on 1) The changes to be expected in the occurrence of pest organisms, 2) Changes to be expected in the regional farmers‘ cropping preferences owing to shifts in yield patterns and plant protection strategies, and 3) Possible changes of the ecological potential of the agricultural landscapes supporting the compensation of negative effects of pesticide application, e.g. on biodiversity. So far, the results have not been published. They further raised awareness to the KLIMAtiv project ongoing at the Julius-Kühn-Institute, which deals with the very specific topic “Climate-neutral fumigation processes and alternative treatment methods for the export of round timber.” Also, at their webpages UBA-publications regarding climate change can be found. For example, the “2023 Monitoring Report on the German Strategy for Adaptation to Climate Change” (UBA, 2023), which gives insights on expected changes in climate in Germany. While the report does not provide details on PPP fate directly, it gives insight on relevant topics which directly impact the environmental fate of PPP, like trends in soil moisture (decreasing), rainfall erosivity (increasing due to higher rainfall intensities), soil temperature (increasing) and organic carbon content (appears to be relatively stable in a case study). It also provides information on how climate change is impacting plant growth, crop distribution, and irrigation in Germany.
The Health and Safety Executive (HSE) Environmental Fate and Behaviour Team (for Great Britain and Northern Ireland) has recently updated the higher tier drainflow (HTDF) assessment using MACRO5. In this context the meteorological files were updated to use data from 1989 to 2020 instead of 1957 to 1989, as used previously. They are also in the process of updating the cropping statistics which are used for the approach 2 in the HTDF assessment, which will reflect crop and weather data from 2018–2020. Further a research project was performed investigating the impacts of climate change on pesticide use and integrated pest management strategies (Bradshaw, 2024) using a case study of the Cabbage Stem Flea Beetle in oilseed rape crops. It concluded that “the case study demonstrates the high value of using models in the decision process. However, significant knowledge gaps were identified that currently limit the utility of modelling approaches to properly evaluate the impacts of climate change. The impact of floods and droughts on the soil ecosystem was highlighted as a research priority, together with the role of rainfall in pest and predator life cycles.”
More relevant publications on climate change and its impact on pesticide for Great Britain can be found at the APHA Science blog and the UK Government’s Climate risk Assessment portal. Also, it was pointed out that a recent EPPO Bulletin (Kriticos et al., 2024) compiles several publications around the impact of climate change on pest risk assessment. IPCC and FAO published a report on how climate change impacts plant health (IPPC Secretariat, 2021).
A report (“An assessment of the impacts of climate change on the fate and behaviour of pesticides in the environment”) was shared by HSE (DEFRA, 2004), which despite being 20 years old, appears to be highly relevant in the current context. “The work in this report is in response to a call from the Pesticide Safety Directorate (PSD) of the Department for Environment, Food and Rural Affairs (Defra) (call CTX 0313) for Expressions of Interest to ‘explore climate change and its implications for regulatory assessment of the fate and behaviour of pesticides in the environment’, to ‘examine how such potential changes will impact on pesticide levels in the soil, ground and surface waters and air compartments’, and to answer the question ‘will weather [climate] information used in environmental exposure and fate modelling of pesticides continue to be appropriate or will changes need to be incorporated?’.” Since the principals in the risk assessment of PPP in the EU have not been changed to a larger extend in the recent 20 years, it is assumed that the conclusions drawn in DEFRA (2004) are in principle still valid.
In section 4.2 an evaluation is presented in which the findings from year 2004 for the UK are put into context for Northern Europe in year 2024.
The Danish Environmental Protection Agency (DEPA) has published the findings of the PRECIOUS project (DEPA, 2013). It evaluated the implication of direct (precipitation, actual evapotranspiration, and temperature) and indirect (crop rotations, crop management, and pesticide use) climatic factors on pesticide-leaching use the MACRO-model version 5.1. It was concluded that no major increase in pesticide leaching of strongly sorbing herbicides, fungicides and insecticides is to be expected. An increased leaching of low dosed herbicides and a minor increase of leaching of other normally-dosed herbicides was found. Direct climatic factors will have implications especially in loamy soils (increased macropore flow), while indirect factors may only have a limited impact. Overall leaching risk by future climatic factors was found to decrease for sandy soils and increase for loamy soils.
With the catchment scale model MACRO-MIKE SHE changes in pesticide concentration in the aquatic environment was performed. The simulations showed that drainage increases, while baseflow and surface runoff receive less water. Again, concentrations for low dosed herbicides increased under future climatic conditions, while concentrations of normally-dosed herbicides and fungicides decreased.
Further opinions shared were that besides adapting the weather data it should be reviewed if the normalisation to 20 °C is still appropriate and in how far temperature dependency of sorption plays a role and might be enhanced due to climate change.
3.2.2 Summary feedback “industry”:
Industry is primarily engaged in climate change activities by anticipating new or changing pest pressures and the necessity to adapt GAPs or to introduce new uses in response to that. Research activities appear to be focused on the discovery of crop protection solutions and application methods that will provide adapted and sustainable support to farmers in the future (e.g. possible changes in cropping patterns, agronomic practices, pest populations, diseases or weeds, that are induced by climate change).
Some examples of climate change impact were provided. Crops like sugar beets may be subject to increased pressure of weeds (Ramesh et al., 2019), and the dormancy of oilseed rape might be affected by mild winters leading to earlier growth and higher exposure to pathogens (Gautam et al., 2013; Brown et al., 2019). Also, it is expected that fungi can adapt to and benefit from higher temperatures and CO2 concentrations (Mboup et al., 2011; Carter et al., 1996). Warm winters and higher precipitation will result in that the number of pathogens moving northward will increase as increasing temperature makes the previously inclement areas more conducive, as well as an increased pest resistance (Gautam et al., 2013; Harvell et al., 2011; Juroszek and Tiedemann, 2013; Ma et al., 2021; Skendzik et al., 2021).
Regarding extreme weathers it is observed that the seed production sector is affected by droughts and floods, sorghum is slowly replacing maize in some areas, as it uses less water, and some crops are slowly disappearing from crop rotation programs. Also access to crops become challenging in wet weather, which may lead to changes in equipment towards e.g. drones.
Adaptations by industry include breeding for improved drought tolerance and increased disease-resistance (Miedaner and Juroszek, 2021 a and b) and developing crop varieties with increased resilience to climate change/extreme weather events applying plant breeding techniques like gene editing (CRISPR).
Climate change was also identified for its relevance to research on implications for pollinators in e.g. Willcox et al (2023).
Kühnel and Wang (2024) compared PECsw values calculated with weather data from 1975–1994 with calculations based on weather data from 2004–2023. They found that in some cases the risk is potentially underestimated and conclude that an update of the current FOCUS surface water scenarios is suggested, taking recent weather and the high variability between years into account.
Otherwise, there is continued involvement of industry members in working groups updating and developing scenarios for pesticide registration (e.g. SETAC SDLM and FOCUS SW repair). It was pointed out that SETAC SDLM prepared adjusted pedoclimatic association maps using the grid-based MARS 25 meteorological database which suggest an expansion of some scenarios from southern Europe, while some scenarios from central and northern Europe appear to become less relevant. For further details on updated weather series and spatial extend of crops etc. the SETAC SDLM working group should be contacted.
FOCUS SW repair (EFSA et al., 2020) has updated weather data of the FOCUS surface water scenarios to replace the 1-year assessment with a 20-year assessment period. However, it was pointed out that it was not in the remit of this working group to reassess the validity of the current FOCUS surface water scenarios with respect to weather, soil or crop conditions. Nevertheless, it is expected that at some point in the future EFSA might initiate a reconsideration of the weather files.
It is considered readily accepted that climate change is changing agricultural strategy. Existing modelling scenarios may remain a valid basis for evaluation of exposure potential if they continue to provide a form of “pedoclimatic risk envelope” to support risk assessments. The 80th percentile values currently used for calculation of predicted environmental concentrations in groundwater and surface water might still be representative for changes in rainfall.
The relevance of the scenarios for the Member States may change but they might continue to have validity. A review of the representation of specific soil type and climate scenarios for different Member States could be necessary to ensure the appropriate scenarios are being applied in order to ensure that modelling outcomes reflect local conditions with a changing climate.
The timings of when crops reach certain growth stages in the FOCUS scenarios (as provided in AppDate (Klein, 2019)) or in Sweden as proposed by Myrbeck (1998) might need reconsideration and update. CropLife Europe published an open-source pan-European Crop Development database and noticed a deviation of observed dates and dates suggested by AppDate (Hughes et al., 2023). It was concluded that “C2D2 has the potential to assist with the parametrization and calibration of more dynamic crop models in FOCUS with varying levels of complexity. At the simplest level, the key crop development dates for each FOCUS scenario could be revised; at an intermediate level, the growing degree days between the key crop development stages could be determined (PEARL can already use heat sums to dynamically grow crops); and at an advanced level, the data could be used to calibrate more sophisticated crop models.”
Further, increased temperatures would affect microorganisms, with different functional temperature ranges and effects on these might affect degradation of substances.
From the effects side, no need was identified to amend the standard ecotox species required in the assessment as these have been selected based on their sensitivity to stressors and not on their representativity of a crop type or environmental conditions. Climatic conditions are controlled in the laboratory and standardized accordingly, and so toxicity data for the risk assessment would still be applicable.
However, implications on field studies may need to be considered. With weather conditions becoming more variable this could impact the spatial and temporal abundance of different species. For example, in earthworm field trials conducted during hot dry summers would result in natural low abundance which would increase the variability shown in field. Normal operating ranges under different conditions should be established to balance this variability from actual effects of crop protection products. This is a critical point for high tier testing and monitoring purposes to ensure correct interpretation of data.
Also, it was pointed out that initiatives on EU level are taken to change the fundamentals of the risk assessment to a more landscape-based process, which also might include effect modelling and combined assessment with other chemicals (e.g. EU-PARC project).
3.2.3 Summary feedback “research institutions”:
The majority of the feedback from the research institutions displayed the opinion that certain adaption to climate change will be required. In the Northern zone, crops, agricultural practices, and crop protection needs will change (and have already begun to do so). Moreover, in the future, boreal areas might become more important food producers as climate will decrease crop yields in currently intensively cultivated areas. Pesticide fate should be studied in the new environment. The new environmental conditions should be represented in pesticide registration. Realistic climate scenarios for PPP registration would be a step and could include recent extreme years.
However, some researchers were of the opinion that the effects based on climate change are smaller than the diversity throughout Europe and/or the uncertainty of the models and therefore an adjustment would not necessarily be required.
Fate and Exposure:
Many of the existing fate and exposure models and methods are based on climatic and environmental conditions that are now outdated due to the rapid climate change observed in recent decades. Updating these models is essential to ensure that they remain accurate and reliable in predicting the environmental behaviour, efficacy and safety of plant protection products under new climate conditions. For example, heavy rain events will increase entries of plant protection products from fields into water bodies by run-off and erosion. Irrigation affects the transport of substances in the soil. Degradation processes are affected by temperature and, in the case of photolysis, light conditions.
It was pointed out that short-term intense rainfalls have and will become more frequent. Current models (like FOCUS PEARL and FOCUS PELMO) usually use daily weather data and it is unclear if the models can accept high-resolution weather data on hourly or sub-hourly basis. In case the models can deal with this higher resolution (e.g. MACRO) a limiting factor might be the availability of reliable long-term data with respective high resolution over time. Also processes or parameters like the runoff curve number (as used in PRZM) might need to be adapted. The curve number approach is an event-based approach and can by definition not use sub-event rainfall intensities. The usage of the CN-approach to calculate surface runoff in models like PRZM is generally problematic since the approach was developed to estimate the direct combined runoff (excluding baseflow) and not only surface runoff. Further it was developed for single large rainfall events on catchment scale and not for continuous time series on plot or field scale (Garen and Moore, 2005).
A member of the ISMC (The International Soil Modeling Consortium) pointed out that the representation of the soil in most of the current models is insufficient. They are considered as rigid and temporally invariable with limited consideration of their structure. The inclusion of a dynamic soil structure and temporally variable soil properties has been recommended and supported by the publications of Hirmas et al. (2018), Sullivan et al. (2021), and Weber et al. (2024). These assumptions of dynamics in soil might become more important with climate change in the Northern Zone due to more frequent freezing-thawing cycles.
Effects:
Climate change will affect pest pressure including the presence of invasive pest species. Crops may be more sensitive to pests due to environmental stress (high temperature, droughts). Non-target organisms may be more sensitive to pesticides due to additional stress caused by climate change.
Detailed feedback was received from Prof. Dr. Matthias Liess from Helmholtz- Centre for Environmental Research (UFZ):
Insecticides are currently used sparingly, especially in northern Europe. It is to be expected that more insecticides will be used in northern regions of Europe due to climate change. The main reason for this is the increased occurrence of harmful insects due to higher temperatures. (Kattwinkel et al., 2011).
Furthermore, it is expected that there is a change in a variety of other ecologically relevant factors. These include, for example, the temperature in water bodies and a changed runoff regime. At first glance, it is to be expected that this multitude of stressors will lead to an increased sensitivity of the organisms in the ecosystem. In a large number of studies, we have found that the same amount of an insecticide can be up to 100 times more potent if an additional stressor such as temperature (Shahid et al., 2024), pH, lack of food (Liess et al., 2020), oxygen deficit, and the like is present. Based on such knowledge, we have developed a model that can quantitatively predict the effect of these combined stressors on populations (Liess et al., 2016). An increased sensitivity, especially of sensitive species, can thus be expected (Moe et al., 2013).
However, all levels of biological organisation adapt to stressors. Individual tolerance against pesticides increases when individuals are exposed to pesticides (Becker et al., 2020). Also, the community composition adapts to pesticides but also to other environmental stressors as temperature. Accordingly, the adaptation of the community to pesticide stress in the field can be used as an indicator of pesticide pollution. For example, the national monitoring of small streams in Germany showed that 80% of these habitats showed a reduction in pesticide-vulnerable species (Liess et al., 2021).
However, the adaptation of the community to stressors also means that fewer potentially synergistic stressor combinations enhance the effect of pesticides. This is also the reason for the observation that the pesticide indicator described above is applicable in different climate regions and that comparable toxicity also causes a comparable effect. For example, in Northern and Southern Europe (Schäfer et al., 2012), as well as in Central Africa (Ganatra et al., 2021).
For risk assessment in a world of changing climate, this means that it is crucial to evaluate the degree of adaptation of the communities under investigation to climate change in order to be able to detect any synergistic effects of pesticides at elevated temperatures.
Further research on the effect of climate change on efficacy (including resistance risk), bee protection, impact on beneficials is performed within several projects at the Julius-Kühn-Institute (e.g. OPTAKLIM, KARO, AVOID, KLIMATIV).
A number of relevant scientific publications were performed at research institutions in the Nordic zone.
From 2006 to 2009 the “Ilmasopu [Adaptation to climate change in the agricultural and food economy]” project took place at LUKE in Finland. Pesticide fate modelling played a minor role, but calculations were performed for a single soil and climate scenarios based on IPCC A2 scenarios and measured long term data. Results are published in Ilmasopu (2009) in Finnish language.
Steffens et al. (2015) performed simulations with the regional model MACRO-SE for south-west Sweden in order to assess the direct and indirect effects of climate change on herbicide leaching to groundwater. One of the main conclusions was that the increased temperature (enhancing degradation) and increased rainfalls (promoting leaching) cancel each other at regional scale, so that only a minor increase in concentrations were observed. Indirect effects (such as increase of land-use area in Sweden and increase of herbicide use) may have a larger effect on groundwater contamination. Steffens et al. (2014) point out the importance of uncertainty analysis when assessing climate change impacts on pesticide leaching and suggest that climate uncertainty should be accounted for by applying an ensemble of different climate scenarios. Both magnitude and direction of predicted changes in pesticide leaching strongly depended on the particular climate scenario. They conclude that an aggregated ensemble prediction has the potential to provide robust probabilistic estimates of future pesticide losses.
Besides changes in land-use also more frequent freezing-thawing episodes in the Northern Zone may become more important. Holten et al. (2018 and 2019) found that significantly more pesticides leached from frozen than from unfrozen soil columns and that rapid breakthrough of pesticides indicated preferential flow in frozen soil. This indicates that more frequent changes will have an impact on the dynamics of pesticide leaching.
Wenng et al. (2020) found that the thermal growing season length has significantly increased in 4 out of seven Norwegian catchments (from 1991–2017). Additionally, a couple of long-term monitoring studies (hydrology and pesticide) in the Northern Zone have been performed, pointing out the importance of continued monitoring to observe trends over time (Stenrod, 2015; Wenng, 2021).
Mentzel et al. (2021) employed the WISPE model to model predictions of risk quotients of pesticides in Northern Europe. A Bayesian Network (BN) model was used to account for variabilities of the predicted pesticide exposure in agricultural streams, and inter-species variability in sensitivity to the pesticide among freshwater species. The conclusions were similar to the findings of Steffens et al. (2014 and 2015). Direct effects of climate change (temperature and rainfall) had a limited effect on predicted concentrations, however indirect effects (like increase in use rates) of course lead to a larger increase. Mentzel et al. (2021) concluded that a probabilistic approach including multiple climate models and scenarios may have the potential to support regulatory needs.
Hader et al. (2022) reviewed existing “literature to identify research that will enable scenario-based forecasting of environmental exposures to organic chemicals in European agriculture under global change.” They identified the following key research gaps: improved understanding of relationships between global change and chemical emissions in agricultural settings; better understanding of environment-microbe interactions in the context of chemical degradation under future conditions; and better methods for downscaling climate change-driven intense precipitation events for chemical fate and transport modelling. Based on this a set of narrative Agricultural Chemical Exposure Scenarios are introduced as a framework for forecasting chemical exposure in European agriculture.
Several working groups exist with participation from research institutions which indirectly consider impacts of climate change. For example, the above mentioned SETAC SDLM group (Spatially Distributed Leaching Modelling). “The goal is to establish a standard SDLM method to be used according to the FOCUS groundwater tiered approach (FOCUS, 2014, Sanco/13144/2010, version 3, 10 October 2014) where this is foreseen as Tier 3b.” It should also support groundwater monitoring which is included as Tier 4 in the FOCUS tiered approach. In this activity new actual data (e.g. climate maps, soil maps, FOCUS zone maps) will be used.
The QTOX working group (“Quantitative extrapolation in ecotoxicology”) “will develop mechanistic knowledge and data efficient modelling tools to bridge the gap between standard toxicity data (typically acute effects of single chemicals) and ecologically relevant end points arising from chronic, time variable exposures to chemical mixtures. The results will be achieved through an interdisciplinary and intersectoral research and training program in which 10 doctoral candidates will characterise the mechanistic processes describing the successive events from exposure to ecosystem-level effects and develop models for extrapolation of adverse effects across levels of biological organisation under environmentally realistic conditions. Notably, the effects of chemical mixtures, dynamic exposure conditions and their interaction with climate change scenarios will be characterised in a series of mesocosm experiments at three sites in central and southern Europe.”6. Part of this project is “Model validation and climate change scenarios” in which mesocosm studies are conducted to analyse effects of chemicals and will be used as case studies for modelling.
The EESE project (EU Environmental scenarios for ERA of non-target organisms, Reference OC/EFSA/PREV/2023/02) does not address effects of climate change directly. However, the main goal of the project is to collect, generate and analyse data to develop environmental scenarios to advance the environmental risk assessment of PPP under Regulation (EC) No 1107/2009. Thus, using literature data as well as field monitoring will provide data on non-target organisms in agricultural landscapes covering different biogeographical regions and climatic zones.
The UFZ has several research projects in Europe and Africa of which results are related to climate change. They are leading the EU PARC project “Reduce complexity of models for predictions of environmental effects of plant protection products while ensuring their predictive capacity.” and “Implementation of the National Action Plan for the Sustainable Use of Plant Protection Products (NAP) - Part 4: Analysis of the contamination of small water bodies in the agricultural landscape with pesticide residues. UBA small water body monitoring.”