Projected Oceanographical Changes in the Baltic Sea until 2100

2020 ◽  
Author(s):  
H.E. Markus Meier ◽  
Sofia Saraiva
Keyword(s):  
Baltic Sea ◽  
21St Century ◽  
Greenhouse Gas Emission ◽  
Regional Climate ◽  
Future Climate ◽  
Nutrient Load ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Early 21St Century ◽  
The Baltic

In this article, the concepts and background of regional climate modeling of the future Baltic Sea are summarized and state-of-the-art projections, climate change impact studies, and challenges are discussed. The focus is on projected oceanographic changes in future climate. However, as these changes may have a significant impact on biogeochemical cycling, nutrient load scenario simulations in future climates are briefly discussed as well. The Baltic Sea is special compared to other coastal seas as it is a tideless, semi-enclosed sea with large freshwater and nutrient supply from a partly heavily populated catchment area and a long response time of about 30 years, and as it is, in the early 21st century, warming faster than any other coastal sea in the world. Hence, policymakers request the development of nutrient load abatement strategies in future climate. For this purpose, large ensembles of coupled climate–environmental scenario simulations based upon high-resolution circulation models were developed to estimate changes in water temperature, salinity, sea-ice cover, sea level, oxygen, nutrient, and phytoplankton concentrations, and water transparency, together with uncertainty ranges. Uncertainties in scenario simulations of the Baltic Sea are considerable. Sources of uncertainties are global and regional climate model biases, natural variability, and unknown greenhouse gas emission and nutrient load scenarios. Unknown early 21st-century and future bioavailable nutrient loads from land and atmosphere and the experimental setup of the dynamical downscaling technique are perhaps the largest sources of uncertainties for marine biogeochemistry projections. The high uncertainties might potentially be reducible through investments in new multi-model ensemble simulations that are built on better experimental setups, improved models, and more plausible nutrient loads. The development of community models for the Baltic Sea region with improved performance and common coordinated experiments of scenario simulations is recommended.

scholarly journals Oceanographic regional climate projections for the Baltic Sea until 2100

2021 ◽  
Author(s):  
H. E. Markus Meier ◽  
Christian Dieterich ◽  
Matthias Gröger ◽  
Cyril Dutheil ◽  
Florian Börgel ◽  
...  
Keyword(s):  
Sea Ice ◽  
Baltic Sea ◽  
Climate Model ◽  
Regional Climate ◽  
Future Climate ◽  
Nutrient Input ◽  
The Baltic Sea ◽  
Marine Biogeochemistry ◽  
The Baltic ◽  
The Impact

Abstract. Recently performed scenario simulations for the Baltic Sea including marine biogeochemistry were analyzed and compared with earlier published projections. The Baltic Sea, located in northern Europe, is a semi-enclosed, shallow and tide-less sea with seasonal sea ice cover in its northern sub-basins and a long residence time causing oxygen depletion in the bottom water of the southern sub-basins. With the help of dynamical downscaling using a regional coupled atmosphere-ocean climate model, four global Earth System Models were regionalized. As the regional climate model does not include components for the terrestrial and marine biogeochemistry, an additional catchment and coupled physical-biogeochemical model for the Baltic Sea were used. In addition to previous scenario simulations, the impact of various water level scenarios was examined as well. The projections suggest higher water temperatures, a shallower mixed layer with sharper thermocline during summer, reduced sea ice cover and intensified mixing in the northern Baltic Sea during winter compared to present climate. Both frequency and duration of marine heat waves would increase significantly, in particular in the coastal zone of the southern Baltic Sea (except in regions with frequent upwelling). Due to the uncertainties in projections of the regional wind, water cycle and global sea level rise, robust and statistically significant salinity changes cannot be identified. The impact of changing climate on biogeochemical cycling is considerable but in any case smaller than the impact of plausible nutrient input changes. Implementing the proposed Baltic Sea Action Plan, a nutrient input abatement plan for the entire catchment area, would result in a significantly improved ecological status of the Baltic Sea and reduced hypoxic area also in future climate, strengthening the resilience of the Baltic Sea against anticipated future climate change. While our findings about changes in variables of the heat cycle mainly confirm earlier scenario simulations, earlier projections for salinity and biogeochemical cycles differ substantially because of different experimental setups and different bioavailable nutrient input scenarios. During the time in which this paper was prepared, shortly before submission, Christian Dieterich passed away (1964–2021). This sad event marked the end of the life of a distinguished oceanographer and climate scientist who made important contributions to the climate modeling of the Baltic Sea, North Sea and North Atlantic regions. 

scholarly journals The climate in the Baltic Sea region during the last millennium simulated with a regional climate model

2012 ◽  
Vol 8 (5) ◽  
pp. 1419-1433 ◽  
Author(s):  
S. Schimanke ◽  
H. E. M. Meier ◽  
E. Kjellström ◽  
G. Strandberg ◽  
R. Hordoir
Keyword(s):  
Baltic Sea ◽  
Climate Model ◽  
Regional Climate ◽  
Last Millennium ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Baltic Sea Region ◽  
The Baltic ◽  
The Impact

Abstract. Variability and long-term climate change in the Baltic Sea region is investigated for the pre-industrial period of the last millennium. For the first time dynamical downscaling covering the complete millennium is conducted with a regional climate model in this area. As a result of changing external forcing conditions, the model simulation shows warm conditions in the first centuries followed by a gradual cooling until ca. 1700 before temperature increases in the last centuries. This long-term evolution, with a Medieval Climate Anomaly (MCA) and a Little Ice Age (LIA), is in broad agreement with proxy-based reconstructions. However, the timing of warm and cold events is not captured at all times. We show that the regional response to the global climate anomalies is to a strong degree modified by the large-scale circulation in the model. In particular, we find that a positive phase of the North Atlantic Oscillation (NAO) simulated during MCA contributes to enhancing winter temperatures and precipitation in the region while a negative NAO index in the LIA reduces them. In a second step, the regional ocean model (RCO-SCOBI) is used to investigate the impact of atmospheric changes onto the Baltic Sea for two 100 yr time slices representing the MCA and the LIA. Besides the warming of the Baltic Sea, the water becomes fresher at all levels during the MCA. This is induced by increased runoff and stronger westerly winds. Moreover, the oxygen concentrations in the deep layers are slightly reduced during the MCA. Additional sensitivity studies are conducted to investigate the impact of even higher temperatures and increased nutrient loads. The presented experiments suggest that changing nutrient loads may be more important determining oxygen depletion than changes in temperature or dynamic feedbacks.

scholarly journals Cost Effectiveness of Ecosystem-Based Nutrient Targets—Findings from a Numerical Model for the Baltic Sea

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2679
Author(s):  
Ing-Marie Gren ◽  
Wondmagegn Tirkaso
Keyword(s):  
Baltic Sea ◽  
Programming Model ◽  
Nutrient Load ◽  
Nutrient Loads ◽  
Buffer Strips ◽  
The Baltic Sea ◽  
Nitrogen Emissions ◽  
The Baltic ◽  
The Cost ◽  
Marine Basins

An ecosystem-based management of a large sea can give heterogeneous nutrient load targets for different parts of the sea. Cost effective solutions to heterogeneous nutrient reductions targets based on ecological conditions are compared with the same overall nutrient reductions to the Baltic Sea. To this end, a numerical programming model is used, which includes eight different nutrient abatement measures (fertilizer and livestock reduction, cultivation of catch crops, reduced airborne nitrogen emissions, improved cleaning at sewage treatment plants, construction of wetlands and buffer strips, and mussel farming) in 21 catchments of the Baltic Sea. The results indicate that the cost for the international agreement on maximum load targets to different marine basins amounts to 5.3 billion euro. This is more than twice as large as the cost for the same total nutrient load targets to the Baltic Sea without specific targets for the marine basins. However, the resulting nutrient loads to the different marine basins deviate from the basin targets where the loads are lower for some basins but can exceed that for one basin, Baltic Proper, by approximately 22 per cent. Whether or not the ecological costs and benefits from deviations in basin targets under the Baltic Sea targets exceed the excess abatement cost of 2.9 billion euro for achieving the marine basin targets remains to be verified.

scholarly journals Uncertainties in projections of the Baltic Sea ecosystem driven by an ensemble of global climate models

2018 ◽  
Author(s):  
Sofia Saraiva ◽  
H. E. Markus Meier ◽  
Helén Andersson ◽  
Anders Höglund ◽  
Christian Dieterich ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
General Circulation ◽  
Climate Models ◽  
Greenhouse Gas Emission ◽  
Nutrient Load ◽  
The Baltic Sea ◽  
Gas Emissions ◽  
The Baltic

Abstract. Many coastal seas worldwide are affected by human impacts such as eutrophication, causing, inter alia, oxygen depletion and extensive areas of hypoxia. Depending on the region, global warming may reinforce these environmental changes by reducing air–sea oxygen fluxes, intensifying internal nutrient cycling and increasing river-borne nutrient loads. The development of appropriate management plans to more effectively protect the marine environment requires projections of future marine ecosystem states. However, projections with regional climate models commonly suffer from shortcomings in the driving global General Circulation Models (GCMs). The differing sensitivities of GCMs to increased greenhouse gas emissions impact regional projections considerably. In this study, we focused on one of the most threatened coastal seas, the Baltic Sea, and estimated uncertainties in projections due to GCM deficiencies relative to uncertainties caused by future greenhouse gas emissions and nutrient load scenarios. To address the latter, transient simulations of the period 1975–2098 were performed using the initial conditions from an earlier reconstruction with the same Baltic Sea model (starting in 1850). To estimate the impacts of GCM deficiencies, dynamical downscaling experiments with four driving global models were carried out for two greenhouse gas emission scenarios, RCP4.5 and 8.5, and for three nutrient load scenarios covering the plausible range between low and high loads. The results of primary production, nitrogen fixation, and hypoxic areas show that uncertainties caused by the various nutrient load scenarios are greater than the uncertainties due to global model deficiencies and future greenhouse gas emissions. In all scenario simulations, a proposed nutrient load abatement strategy, i.e., the Baltic Sea Action Plan, will lead to a significant improvement in the overall environmental state. However, the projections cannot provide detailed information on the timing and the reductions of future hypoxic areas due to uncertainties in salinity projections caused by uncertainties in projections of the regional water cycle and of the global mean sea level rise.

scholarly journals Remediating Agricultural Legacy Nutrient Loads in the Baltic Sea Region

2021 ◽  
Vol 13 (7) ◽  
pp. 3872
Author(s):  
Julia Tanzer ◽  
Ralf Hermann ◽  
Ludwig Hermann
Keyword(s):  
Baltic Sea ◽  
Agricultural Soils ◽  
Economic Benefits ◽  
Current Data ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
Nutrient Emissions ◽  
Long Run ◽  
The Baltic ◽  
Agricultural Legacy

The Baltic Sea is considered the marine water body most severely affected by eutrophication within Europe. Due to its limited water exchange nutrients have a particularly long residence time in the sea. While several studies have analysed the costs of reducing current nutrient emissions, the costs for remediating legacy nutrient loads of past emissions remain unknown. Although the Baltic Sea is a comparatively well-monitored region, current data and knowledge is insufficient to provide a sound quantification of legacy nutrient loads and much less their abatement costs. A first rough estimation of agricultural legacy nutrient loads yields an accumulation of 0.5–4.0 Mt N and 0.3–1.2 Mt P in the Baltic Sea and 0.4–0.5 Mt P in agricultural soils within the catchment. The costs for removing or immobilising this amount of nutrients via deep water oxygenation, mussel farming and soil gypsum amendment are in the range of few tens to over 100 billion €. These preliminary results are meant as a basis for future studies and show that while requiring serious commitment to funding and implementation, remediating agricultural legacy loads is not infeasible and may even provide economic benefits to local communities in the long run.

The integrative potential of science and research cooperation for suturing the Baltic Sea region in the 21st century

2021 ◽  
Vol 19 (3) ◽  
pp. 9-32
Author(s):  
Kazimierz Musiał
Keyword(s):  
Baltic Sea ◽  
Case Studies ◽  
21St Century ◽  
Theoretical Framework ◽  
Baltic Region ◽  
The Baltic Sea ◽  
Research Cooperation ◽  
Baltic Sea Region ◽  
The Baltic ◽  
Science And Research

The aim of the article is to demonstrate how science and researchcooperation may help to reintegrate the Baltic region in the 21st century withthe participation of Russia. This is done through the analysis of documentsand strategies of Baltic Sea regionalism in the context of the regional knowledgeregime. Attention is paid to different positionalities of the regional actorsand their narratives. The theoretical framework is secured by an analysis ofcritical junctures drawing on case studies from the years 1989-91 and 2014 andthe subsequent reconfiguration of the power / knowledge nexus. The analysisshows that this reconfiguration actively contributes to creating and changingthe content and context of the Baltic Sea regionalism as based on new symbolic,economic, and political capitals. The conclusion points to the potentialof Russia’s involvement in the co-creation of the regional knowledge regimeand defines the conditions and methods of possible cooperation.

scholarly journals Coupled regional Earth system modelling in the Baltic Sea region

2021 ◽  
Author(s):  
Matthias Gröger ◽  
Christian Dieterich ◽  
Jari Haapala ◽  
Ha Thi Minh Ho-Hagemann ◽  
Stefan Hagemann ◽  
...  
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Regional Climate ◽  
Model Systems ◽  
Earth System ◽  
The Baltic Sea ◽  
Coupled Models ◽  
Baltic Sea Region ◽  
Ocean Models ◽  
The Baltic

Abstract. Non-linear responses to externally forced climate change are known to dampen or amplify the local climate impact due to complex cross compartmental feedback loops in the earth system. These feedbacks are less well represented in traditional standalone atmosphere and ocean models on which many of today's regional climate assessments rely on (e.g. EuroCordex, NOSCCA, BACC II). This promotes the development of regional climate models for the Baltic Sea region by coupling different compartments of the earth system into more comprehensive models. Coupled models more realistically represent feedback loops than the information imposed into the region by using prescribed boundary conditions, and thus, permit a higher degree of freedom. In the past, several coupled model systems have been developed for Europe and the Baltic Sea region. This article reviews recent progress of model systems that allow two way communication between atmosphere and ocean models, models for the land surface including the terrestrial biosphere, as well as wave models at the air sea interface and hydrology models for water cycle closure. However, several processes that have so far mostly been realized by one way coupling such as marine biogeochemistry, nutrient cycling and atmospheric chemistry (e.g. aerosols) are not considered here.Compared to uncoupled standalone models, coupled earth system models models can modify mean near surface air temperatures locally up to several degrees compared to their standalone atmospheric counterparts using prescribed surface boundary conditions. Over open ocean areas, the representation of small scale oceanic processes such as vertical mixing, and sea ice dynamics appear essential to accurately resolve the air sea heat exchange in the Baltic Sea region and can only be provided by online coupled high resolution ocean models. In addition, the coupling of wave models at the ocean-atmosphere interface allows a more explicit formulation of small-scale to microphysical processes with local feedbacks to water temperature and large scale processes such as oceanic upwelling. Over land, important climate feedbacks arise from dynamical terrestrial vegetation changes as well as the implementation of land use scenarios and afforestation/deforestation that further alter surface albedo, roughness length and evapotranspiration. Furthermore, a good representation of surface temperatures and roughness length over open sea and land areas is critical for the representation of climatic extremes like e.g. heavy precipitation, storms, or tropical nights, and appear to be sensitive to coupling.For the present-day climate, many coupled atmosphere-ocean and atmosphere-land surface models demonstrate added value with respect to single climate variables in particular when low quality boundary data were used in the respective standalone model. This makes coupled models a prospective tool for downscaling climate change scenarios from global climate models because these models often have large biases on the regional scale. However, the coupling of hydrology models for closing the water cycle remains problematic as the accuracy of precipitation provided by the atmosphere models is in most cases insufficient to realistically simulate the runoff to the Baltic Sea without bias adjustments.Many regional standalone ocean and atmosphere models are tuned to well represent present day climatologies rather than accurately simulate climate change. More research is necessary about how the regional climate sensitivity (e.g. the models’ response to a given change in global mean temperature) is affected by coupling and how the spread is altered in multi-model and multi-scenario ensembles of coupled models compared to uncoupled ones.

scholarly journals An integrated simulation model to evaluate national measures for the abatement of agricultural nutrients in the Baltic Sea

2009 ◽  
Vol 18 (3-4) ◽  
pp. 440-459 ◽  
Author(s):  
K. HYYTIÄINEN ◽  
H. AHTIAINEN ◽  
J. HEIKKILÄ
Keyword(s):  
Water Quality ◽  
Simulation Model ◽  
Baltic Sea ◽  
Arable Land ◽  
Gulf Of Finland ◽  
Nutrient Loads ◽  
The Baltic Sea ◽  
The Baltic ◽  
Bothnian Bay ◽  
The Gulf Of Finland

This study introduces a prototype model for evaluating measures to abate agricultural nutrients in the Baltic Sea from a Finnish national perspective. The stochastic simulation model integrates nutrient dynamics of nitrogen and phosphorus in the sea basins adjoining the Finnish coast, nutrient loads from land and other sources, benefits from nutrient abatement (in the form of recreation and other ecosystem services) and the costs of agricultural abatement activities. The aim of the study is to present the overall structure of the model and to demonstrate its potential using preliminary parameters. The model is made flexible for further improvements in all of its ecological and economic components. The results of a sensitivity analysis suggest that investments in reducing the nutrient load from arable land in Finland would become profitable only if the neighboring countries in the northern Baltic committed themselves to similar reductions. Environmental investments for improving water quality yield the highest returns for the Bothnian Bay and the Gulf of Finland, with smaller returns for the Bothnian Sea. Somewhat surprisingly, in the Bothnian Bay the abatement activities become profitable from the national viewpoint, because the riverine loads from Finland represent a high proportion of the total nutrient loads. In the Gulf of Finland, this proportion is low, but the size of the coastal population benefiting from improved water quality is high.;

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