Ina Pohle

Potential impacts of climate change and regional anthropogenic activities in Central European mesoscale catchments.

Abstract The Soil and Water Integrated Model (SWIM) was used to assess potential climate and land-use change impacts in the Central European catchments of Schwarze Elster, Spree and Lusatian Neisse which are heavily influenced by opencast lignite mining. To account for potential climate change, scenarios of two statistical regional climate models, STAR and WettReg, were used. Regional anthropogenic change was considered in terms of increasing cultivation of energy crops (oilseed rape, silage maize, sunflower and sorghum) and decreasing mining activities (decreasing groundwater depression cone). In the climate scenarios, decreased natural discharge, by up to 60% in the long-term average, was simulated. In simulations with climate scenarios and oilseed rape, this effect is halved; the other energy crops have a small additional impact on discharge. The decreasing groundwater depression cone slightly compensates for climate change impacts. Overall, potential impacts of regional anthropogenic activities are secondary to those of climate change. Editor Z.W. Kundzewicz; Guest editor M. White

Trend analysis for integrated regional climate change impact assessments in the Lusatian river catchments (north-eastern Germany)

Trend analysis on observations and model-based climate change simulations are two commonly used methods for climate change detection and impact analysis. Here we propose an integrated assessment and interpretation of climate change impacts as a prerequisite for stakeholder outreach and planning of suitable climate change adaptation measures. The assessment includes (i) identifying trends in meteorological and hydrological observations and their nature, (ii) analysing the relation between the meteorological drivers and generated run-off as an integrated catchment response and (iii) analysing how hitherto changes agree with the simulations by regional climate models (RCMs). The Lusatian river catchments of Spree and Schwarze Elster, characterised by high anthropogenic impact (e.g. mining activities) and low natural water yield, serve as study areas. The results of this study suggest that increases in observed temperature and potential evapotranspiration are robust while observed precipitation remained nearly unchanged (1963–2006). The RCMs agree on simulating a temperature increase but simulate opposing trends for precipitation for both past (1963–2006) and future (2018–2060) periods, the latter inducing differences in the hydrological response (actual evapotranspiration and run-off). For stakeholder outreach, we communicated a range of potential future climates and identified the statistical RCMs (STAR, WettReg) as warm and dry scenarios, and the dynamical RCMs (REMO, CCLM) as wet scenarios. Ultimately, the combined analysis of trends in observations and simulation models can be beneficial for stakeholder outreach and may increase their willingness to plan and implement suitable climate change adaptation strategies which are urgently needed within the Lusatian river catchments.

Potential impacts of climate change on natural and managed discharges of the Rivers Spree, Schwarze Elster and Lusatian Neisse, Central Europe

The water balance of the Rivers Spree, Schwarze Elster and Lusatian Neisse is profoundly disturbed due to large-scale open-cast lignite mining activities and water management. Together with continental climate conditions this affects water resources and water users in the region. Driven by scenarios of the regional climate model STAR which assume increasing temperature and decreasing precipitation, two hydrological models, the Soil and Water Integrated Model SWIM and the catchment model EGMO simulate declining natural discharges in the region. Thus, decreasing managed discharges are simulated with the long term water management model WBalMo. The refinement of the simulation time step of WBalMo from months to weeks improves the consideration of climate variability and is also associated with higher simulated managed discharges in early summer. Management scenarios in terms of a reduced outlet capacity of a mining lake reservoir result in higher releases from other reservoirs and slightly reduced summer discharges in downstream river sections.

Challenges of Reducing Phosphorus Based Water Eutrophication in the Agricultural Landscapes of Northwest Europe

In this paper, we outline several recent insights for the priorities and challenges for future research for reducing phosphorus (P) based water eutrophication in the agricultural landscapes of Northwest Europe. We highlight that new research efforts best be focused on headwater catchments as they are a key influence on the initial chemistry of the larger river catchments, and here many management interventions are most effectively made. We emphasize the lack of understanding on how climate change will impact on P losses from agricultural landscapes. Particularly, the capability to disentangle current and future trends in P fluxes, due to climate change itself, from climate driven changes in agricultural management practices and P inputs. Knowing that, future climatic change trajectories for Western Europe will accelerate the release of the most bioavailable soil P. We stress the ambiguities created by the large varieties of sources and storage/transfer processes involved in P emissions in landscapes and the need to develop specific data treatment methods or tracers able to circumvent them, thereby helping catchment managers to identify the ultimate P sources that most contribute to diffuse P emissions. We point out that soil and aqueous P exist not only in various chemical forms, but also in range of less considered physical forms e. g., dissolved, nanoparticulate, colloidal and other particulates, all affected differently by climate as well as other environmental factors, and require bespoke mitigation measures. We support increased high resolution monitoring of headwater catchments, to not only help verify the effectiveness of catchments mitigation strategies, but also add data to further develop new water quality models (e.g., those include Fe-P interactions) which can deal with climate and land use change effects within an uncertainty framework. We finally conclude that there is a crucial need for more integrative research efforts to deal with our incomplete understanding of the mechanisms and processes associated with the identification of critical source areas, P mobilization, delivery and biogeochemical processing, as otherwise even highintensity and high-resolution research efforts will only reveal an incomplete picture of the full global impact of the terrestrial derived P on downstream aquatic and marine ecosystems.

Creating Community for Early-Career Geoscientists : Student involvement in geoscience unions: A case study from hydrology

The American Geophysical Union (AGU) and the European Geosciences Union (EGU) play central roles in nurturing the next generation of geoscientists. Students and young scientists make up about one quarter of the unions’ active memberships [American Geophysical Union, 2013; European Geosciences Union, 2014], creating a major opportunity to include a new generation of geoscientists as more active contributors to the organizations’ activities, rather than merely as consumers. Both organizations are now explicitly expanding their bottom-up organizational structures to include early-career members (ECMs) by appointing student (AGU) and early-career scientist (EGU) representatives for their scientific divisions. (We refer to “early-career members” because AGU and EGU define student and postdoc members differently). Because this expansion is a recent development, it is still unclear what roles these representatives will play and how these roles will evolve over the coming years. We are ECMs in the hydrological sciences. Here we show how the Young Hydrological Society (YHS) used bottom-up initiatives, aligned closely with the newly appointed AGU and EGU representatives, to help improve the professional development of student and postdoc members by providing opportunities to increase their contributions to the geoscience unions. We call for a conversation on how ECMs can make the best use of these new opportunities to engage proactively with the unions.