Scenarios

Background Paper

Havs- och vattenmyndighetens rapport 2013:4

PrefaceBalticSTERN (Systems Tools and Ecological-economic evaluation – a Research Network) is an international research network with partners in all countries around the Baltic Sea. The research focuses on costs and benefits of mitigating eutrophication and meeting environmental targets of the HELCOM Baltic Sea Action Plan. Case studies regarding fisheries manage-ment, oil spills and invasive species have also been made, as have long-term scenarios regarding the development of the Baltic Sea ecosystem.

The BalticSTERN Secretariat at the Stockholm Resilience Centre has the task to coordinate the network, communicate the results and to write a final report targeted at Governments, Parliaments and other decision makers. This report should also discuss the need for policy instruments and could be based also on results from other available and relevant research.

The final report “The Baltic Sea - Our Common Treasure. Economics of Saving the Sea” was published in March 2013. This Background Paper Scenarios is one of eight Background Papers, where methods and results from BalticSTERN research are described more in detail. In some of the papers the BalticSTERN case studies are discussed in a wider perspective based on other relevant re-search.

ContentS

1. Introduction ............................................................................................................. 4

2. Baltic Sea Scenario Studies ................................................................................. 62.1. Diversity of aspects in the scenario studies ............................................... 6

Methods ......................................................................................................... 6Models ..............................................................................................................7Time scale ........................................................................................................7Uncertainty ......................................................................................................7

2.2. Summaries of selected scenario studies ................................................... 8ECOSUPPORT/ ECOSUPPORT-FISH (BONUS) .................................... 8AMBER (BONUS with RADOST) ............................................................. 8BALTIC-C (BONUS, BALTEX, SEPA) ....................................................... 9RADOST ......................................................................................................... 9ICES (National Fisheries Labs) ..................................................................10IBAM (BONUS) ..........................................................................................10PREHAB (BONUS) .......................................................................................11BALTIC COMPASS (BONUS) ....................................................................11BERAS implementation (Baltic Sea Programme 2007-2013).................. 12MAFIA (Danish Strategic research council) ............................................. 12Maria Granberg (SEPA) ............................................................................... 12Summary ........................................................................................................ 13

3. Global storylines ................................................................................................... 14An overexploited world ............................................................................... 15The Baltic Sea region in an overexploited world ..................................... 15A world in balance .......................................................................................16The Baltic Sea region in a balanced world ................................................. 17

4. WWF scenarios for the Baltic Sea ................................................................... 18

5. Scenarios used within the BalticSteRn research ......................................20

6. Conclusions and discussion ............................................................................. 22

References ...................................................................................................................24

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1. IntroductionThis paper first gives an introduction to the concept and development of

scenarios. The introduction is followed by a description of how scenarios have been used in recent research projects regarding the Baltic Sea based on a survey undertaken by the BalticSTERN Secretariat. Regional futures will depend on global developments and some global storylines are discussed in Chapter 3. Finally, the scenarios developed by the BalticSTERN research network are described together with the specific scenarios (e.g. agricultural development), which are used as input.

Scenarios for the development of the Baltic Sea until 2050 has been modelled in the BalticSTERN cost-benefit analysis to be able to estimate the environmental situation in an action and a non-action scenario respectively.

The main objective for looking at other scenario work has been to un-derstand whether there are scenarios developed supporting/contradicting the ones used for the cost-benefit analysis in BalticSTERN. The implication of other possible futures for this analysis is discussed. The different directions in which the future might evolve also have bearings on possible management strategies for the Baltic Sea.

It will take time before the implementation of nutrient abatement measures have an effect on the state of the Baltic Sea, implying that the costs of these measures will burden the society ahead of the benefits they generate. There might thereby be a time lag between when decisions are taken and when both costs and benefits have been realized. As described in BG Paper State of the Baltic Sea, the sources and loads behind eutrophication have been changing in the past, and it is likely that they will also change in the future. Therefore, the amount of abatement measures required in meeting the Baltic Sea Action Plan (BSAP) targets might also change depending on whether one thinks the discharges from the specific sources will increase or decrease. This implies that in order to make a cost-benefit analysis, some assumptions regarding the future have to be made, since the size of both costs and benefits will depend on how one believes the future will evolve. How drivers, pressures and thereby the state might change in the future therefore need to be addressed by developing possible scenarios.

Scenarios are archetypal descriptions of alternative images of the future, created from mental maps or models that reflect different perspectives on past, present and future developments (Rotmans & van Asselt, 1998). When developing scenarios regarding Baltic Sea eutrophication, the focus is on illustrating possible future changes of the relevant drivers and pressures behind the state of the Baltic (e.g. how does the occurrence of algae blooms change if agricultural production becomes more intensive). It is important to understand that the objective of scenarios is not to make predictions about the future, but rather to make simulations of some possible futures.

Scenarios usually have a theme, that is, a focal question describing the area of interest and how far in the future they aim to describe. This theme varies between different scenarios, some focus on fishing, others on nutrient load, some develop scenarios for 2030 while other scenarios span to 2100.

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The purpose of developing a scenario for the Baltic Sea could be to:• Describeseveralfuturealternativestates• Communicatelargeamountsofcomplexinformation• Bridgeenvironmentalsciencewithpolicy• Identifyfutureenvironmentalproblems• Focusactiononwhereitisoptimallyimplemented• Raisepublicawareness• Illustrateeffectsofdifferentpolicies(e.g.BSAP)• Generateimportantinputtoresearch• Determineapaththatleadstoawantedstate

A good scenario should be: • internallyconsistent;meaningthatthecombinationoflogicsinascenario

must not have any built-in inconsistency that could undermine the credi-bility of the scenario,

• credible;inthatitisscientificallysound,• plausible;meaningthatitmustfallwithinthelimitsofwhatmightcon-

ceivably happen,• relevant;inthatitshouldgiveinsightsofusefortheissuesaddressed,and• challenging;inthatitshouldchallengetheconventionalwisdomaboutthe

future.

There are many research projects focusing on the Baltic Sea, whose objectives involve the development of scenarios with different themes. Many of these scenarios focus on eutrophication issues by developing scenarios for drivers, pressures and state variables related to this problem with different time horizons. In order to obtain an overview of the scenarios developed for this region, the BalticSTERN secretariat sent out a questionnaire to different research groups in June 2011. An overview of these scenarios is presented in Chapter 2.2.

How the future evolves in the Baltic region is to a large extent linked to how the future evolves globally. For example, agricultural production in the region is to a large degree explained by global market prices for crops. Future climate changes will have indirect (through e.g. land use), as well as direct effects (e.g. water temperature) on the eutrophication of the Baltic Sea. Some scenario studies focus on developing global scenarios in the form of narratives, rather than model driven scenarios. Two possible global futures, one optimistic and one pessimistic, are described in Chapter 3 and downscaled to the Baltic Sea region.

The main purpose of the majority of the scenarios developed within different research projects, described in Chapter 2.2, was to generate im-portant input to research, although they could have other purposes as well. The global and regional storylines described in Chapters 3 and 4 were more likely to be developed towards policy makers, with the purpose to describe future alternative states and identify the challenges related to these.

The scenarios used within the BalticSTERN network focus on eutrophica-tion and describe two possible futures for the Baltic Sea region spanning until the year 2050. These scenarios are described in Chapter 5 and illustrate Baltic Sea development if the HELCOM Baltic Sea Action Plan is implemented compared to a non-action Business-As-Usual (BAU) scenario.

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2. Baltic Sea Scenario StudiesAs previously mentioned, the purpose of developing scenarios for the Baltic Seacanbevaried;forexampleaimingtocommunicatecomplexinformation,bridge science and policy, raise public awareness, describe potential future states of the Baltic Sea or identify future environmental problems.

One of the tasks of the BalticSTERN Secretariat is to communicate also with relevant research projects outside the BalticSTERN network in order to identify related programs and projects that could contribute to the analyses. For this purpose a workshop was arranged with participants from different research projects. An outcome was that it would be of interest to conduct a survey on the use of scenarios in different Baltic Sea research projects. Consequently a questionnaire was developed and sent out in June 2011 in order to create an inventory of the latest scenarios that deal with environme-ntal problems of the Baltic Sea.

Questionnaires were returned for 15+ Baltic Sea scenario studies, which were recent or ongoing at the time of information collection/form retrieval. Of the 15 studies that are reviewed/summarised here, about half were funded fully or partially by BONUS. Other funding bodies were, amongst others, Swedish Environmental Protection Agency (SEPA), Swedish Research Council, BALTEX, National Fisheries Lab, Baltic Sea Programme, FORMAS and the Danish Strategic Research Council.

2.1. Diversity of aspects in the scenario studiesWhile the areas of expertise and questions that the studies were based on differed significantly, most studies had climate or greenhouse gas emission, nutrient loads and - connected to the latter - land use as a major driver or input parameter for their models. Understandably, many studies were either dealing directly with eutrophication and the status of part or the whole of the Baltic Sea, or with the effects of it. The most common output variables were nutrient load, Secchi depth (water transparency) and primary production, and about half of the studies had Baltic Sea Action Plan (BSAP) targets con-sidered in their scenarios as an option for future developments regarding Secchi depth and/or nutrient loads.

Only five of the studies mentioned here had explicitly used downscaled data and trends from global scenarios, and all input of that kind came from the scenarios of the Intergovernmental Panel on Climate Change Special Report Emission Scenarios (IPCC SRES), while three of those studies also made use of previously produced regional scenarios from the Helsinki Commission (HELCOM) and Net Anthropogenic Nutrient Inputs (NANI) agricultural practices.

Methods The majority of regional scenario studies have used a purely analytical approach in the process, while a few also feature stakeholder participation. The analytical approach for scenario development lends itself particularly to the production of quantitative scenarios. In fact the most common way to

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distinguish scenarios from each other is by their qualitative or quantitative character. For the production of quantitative scenarios a relevant computer model is fed with input/driver data and a numerical, quantitative output is obtained to generate the relevant scenario information, and thereafter explore future consequences of applied assumptions. This method may also be em-ployed as a tool to check the consistency of qualitative scenarios that explore futures in narrative texts, called storylines, and is particularly used when data is weak. Qualitative scenarios are ideal for presenting the views of several stakeholders and experts at the same time, particularly when a participatory approach, that is scenario panel with representatives from various groups, employed in the development process. The analytical studies summarised in this chapter therefore mainly produced quantitative outputs, while some also include some descriptive form of scenarios.

ModelsThe list of models that have been used in the presented reports is long and diverse. These models were used to connect for example climate input to land use, agricultural production and nutrient load. Models that were applied in several studies are HadCM3 and ECHAM (general climate models), RCAO (regional ocean-atmosphere model), RCA (regional atmosphere model), ERGOM (biogeochemical model from IOW in Germany), Scobi (biogeochemical model from SMHI, Sweden), BALTSEM (biogeochemical model from BNI, Sweden) and Ecopath with Ecosim (dynamics food-web model). These models were mostly shared between studies in the projects ECOSUPPORT and the related AMBER, as well as BALTIC-C (all three funded by BONUS).

Time scaleThe time span that the different studies address ranges from just a few months into the future until the end of the 21st century. Scenarios and predictions that cover the next five years or less can technically not be classed as scenarios as such, but rather show trends. The furthest-reaching scenarios are ECO-SUPPORT/ECOSUPPORT-FISH, AMBER, RADOST, BALTIC-C, BECC and those from BNI. Studies spanning as far as to 2050 are ICES, MTT/PROBABS and BALTIC COMPASS. PREHAB orientates itself at the BSAP frame of 2021, and the remaining reports look at developments closer to present day.

UncertaintyMost scenario authors are very aware of the limitations of their models and the resulting data. An ensemble approach, in which multiple models are used together in order to obtain an improved predictive performance, has been utilised in some cases in order to minimise errors, and in some cases redundant models have been employed. Furthermore, IBAM authors point out the im-pact of uncertainty on risk assessment, and advocate the use of an integrative Bayesian decision analytical model to avoid underestimating total risks, as well as to decrease the uncertainty in future analyses by including existing knowledge on prior probabilities of parameters. In Bayesian statistics prior (initial) probabilities are specified, which are then updated in the light of new,

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relevant data. This allows a dynamic risk assessment with justified uncertainty estimates, in which different driving forces that create environmental impacts and pressures are considered together rather than separately.

2.2. Summaries of selected scenario studies ECOSUPPORT/ ECOSUPPORT-FISH (BONUS)The aim of this project was to create a multi-model system tool for the assess-ment of effects on the Baltic Sea resulting from climate change and nutrient loads. For this purpose, scenarios were generated in a sequential process by running a catchment model forced by a climate model and human activity on land (that is agricultural intensity) for nutrient loads and discharge. These outputs were fed into three different marine biogeochemical models that were also forced by IPCC SRES climate scenarios. The results from these runs form the input for a food-web model that yields potential fish stocks (i.e. cod, herring, sprat) for a climate and nutrient scenario respectively. The subse-quent 16 (four IPCC SRES climate scenarios with four HELCOM nutrient load scenarios including Business As Usual (BAU) and BSAP implementa-tion) qualitative scenarios are based on analysis rather than participation of stakeholders. The overall result was that climate warming, along with a likely increase of surface water run-off, would worsen eutrophication. While reaching BSAP targets may still be possible to achieve, it would require tough measures on both wastewater and agricultural management. All ECOSUPPORT climate runs, including the ones that assume lower CO2 emissions, in fact show deteriorating or at least not improving, effects regarding eutrophication. As climate change may counteract nutrient load reductions, additional nutrient reductions in addition to what is currently proposed by the BSAP, must be made in order to reach the targeted water quality status. The overall tendency of the Baltic Sea would be to turn into a phosphorus-limited ecosystem, as proposed by other studies. In ecosystems it is unlikely that all nutrients are used up at the same rate. Plants like algae need both nitrogen and phospho-rus sources in order to thrive. When phosphorus is limited, an ecosystem can be described as phosphorus-limited since primary production, as for example algae growth, is now restricted by the availability of that very element. To re-duce uncertainties in their calculations, the authors used ensemble model-ling.

AMBER (BONUS with RADOST) This BONUS-funded project was looking at the Oder river catchment and created different scenarios for land uses in this area in order to investigate the potential consequences of nutrient discharges. Politically induced changes of land use (three different scenarios: BAU, intensification with regional market support or “extensification” with trade liberalisation), as well as specific cir-cumstances such as the cultivation of energy maize or development of animal stock sizes (three wild cards) were simulated. As in ECOSUPPORT, the scenarios were aligned with IPCC SRES scenarios. Results indicate that, as a result of implementation of the Urban Waste Water Treatment Directive (UWWTD), nitrogen loads are likely to increase, while phosphorus loads will

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remain the same or decrease in the Oder river. The agricultural intensification scenario indicates an increase of nitrogen emissions and a re-intensification is already observable in the region, while a nitrogen emission-reducing “ extensification” development appears less likely at this stage. The authors do not assume that a good water quality status will be reached for the Oder catchment area under the investigated conditions. The currently nitrogen-limited (productivity constrained by availability of nitrogen) Oder lagoon in the Oder estuary will experience an increase of algae blooms with an increase of nitrogen emissions. An increased release of phosphorus from the sediment under climate warming conditions can also be expected. This will, in the fu-ture phosphorous-limited Baltic Sea, bring phosphorous back into circulation and lead to increased algae blooms. The authors see a further reduction of phosphorus for the Baltic Sea in general as vital and propose further im-provement of wastewater treatment.

As proposed also by ECOSUPPORT authors, the AMBER scenarios suggest a need for strong political measures if goals such as the BSAP targets are to be reached. High reductions will be required particularly from Poland. Since point sources will be covered by UWWTD, the focus should be on the agricultural sector and the prevention of inappropriate fertilizer use.

BALTIC-C (BONUS, BALTEX, SEPA)The aim of this project was to develop an integrated ecosystem model frame-work, based on the cycling of organic carbon and carbon dioxide, that is the exchange/recycling of carbon through decomposition processes from dead organic matter such as plants within the Baltic Sea water and drainage basin. Included was also the carbon exchange between water and the atmosphere, as well as at sediment interfaces. Four NANI derived lifestyle scenarios for nutrient loads were employed: 1) BAU (3 per cent increase of animal product consumption), 2) 20 per cent fertiliser use increase and increased human consumption of animal products, 3) 20 per cent decrease of atmospheric dep-ositions according to NEC directive, 4) Adjustment to EU-15 level of nutrient fluxes. In total 15 scenarios were created using different models and assuming different levels of nutrient loads including BAU and BSAP, while land change scenarios consistent with IPCC SRES narratives were adopted from the EU-FP7 ALARM project and combined with IPCC SRES scenarios. The results were an expected overall increase of dissolved organic carbon (DOC) in all scenarios compared to present levels by +30 to +43 per cent. Under a warmer and moister climate and a high atmospheric CO2 concentration, the Baltic Sea is likely to be more acidic and a higher DOC export from terrestrial eco-systems can be expected. These likely developments call for management tools that allow mitigation actions for eutrophication, climate change and the connected acidification of the Baltic Sea.

RADOSTLike the previous studies, the scenarios within RADOST were also nested within the global storylines and trends of IPCC SRES scenarios. RADOST ran simulations of the effects of climate change on the western Baltic Sea

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under consideration of BSAP targets until the year 2100. Although the global acceleration rate for sea level rise has not been observed for the Baltic Sea, an increase in water temperature of up to 3 degrees Celsius and a significant decrease of salinity is indicated by the models. As mentioned in the projects above, the Baltic Sea is likely to become a phosphorus-limited system under BSAP implementation, with a reduction of algae blooms in summer and with improved Secchi depth as well as oxygenation status. While climate warming will have detrimental effects on the water quality, the BSAP implementation will have a far stronger impact in comparison. The authors also suggest for-mulation of new water quality objectives since Secchi depth alone (see BSAP) is not suitable as the sole indicator for eutrophication.

ICES (National Fisheries Labs) Central for the ICES project were the long-term predictions of Baltic herring recruitment (any juvenile fish surviving and which contribute towards the population numbers) under different fishing effort and climate change scenarios. Incorporating IPCC SRES assumptions for high and low emissions, the models showed that climatic change could have a positive effect on her-ring recruitment by raising the sea surface temperature in the central Baltic. The simulations showed a moderately positive trend in herring stock trajecto-ries even under elevated fishing mortality. In contrast, a low value for herring populations was only seen in the scenario runs that assumed no climate change and a high fishing intensity at the same time, while a lower fishing intensity promises to yield higher catches in the long term. The authors found that sea surface temperature serves as an important predictor for four out of five distinct herring stocks in the Baltic Sea, and suggest that management ought to take into account multispecies interactions in a climate changing framework. For a more holistic management approach, consideration should also be given to socio-economic developments and their implications for changes in stock productivity linked to climate change trends.

IBAM (BONUS) The purpose of the project was to develop an integrative decision analytical model for environmental management of the Gulf of Finland with regards to fisheries, eutrophication, oil spills and hunting of eider, with the aim to utilise scientific data for solving problems in practical management. Within IBAM four scenario simulations were created for a five-year period, as well as six nutrient load scenarios that were based on Finnish and BSAP targets. Amongst other things, they looked at Baltic herring fishing in the Gulf of Finland in the short term to estimate quotas that will help to reduce the risk of overfishing. Additionally, probabilistic estimates (estimated probability of future outcomes) for all decision alternatives were calculated to assess the integrated impact of several risk factors. For this purpose Bayesian models (see above) were used that allow for a more realistic estimation of uncertain-ties by incorporating the knowledge about prior probabilities of model para-meters. The results showed that a decrease in fishing mortality, that is har-vesting, has a much bigger effect on stocks compared to the effect of nutrient load management through nutrient reduction due to the slow reactivity of

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water quality to these measures. Therefore, the authors also propose a Bayesian quota (which considers the uncertainty in stock size) for herring fishing, which will decrease variability in population and the risk of overfishing. Fur-ther improvement of nutrient load models may be achieved by adding the variable of implementation uncertainty, which accounts for the uncertainty of human behaviour, and could help adjust reductions levels appropriately.

PREHAB (BONUS)The aim of the PREHAB project was to provide tools for sustainable develop-ment of the Baltic Sea through empirical and predictive modelling/mapping of habitats and the distribution of species in these habitats. The usefulness of human pressures, for example excess nutrients from agriculture, that is as predictors for environmental status was tested. To achieve this ensemble mod-elling was applied with three different modelling techniques, and three nutri-ent loads scenarios were used that included BAU as well as BSAP targets. Eutrophication/Secchi depth and coastal construction were used as a proxy for assessing the effects of human pressures on perch, pikeperch and certain plant species. The results indicate that the extent of eutrophication has a s ubstantial effect on both fish and the spread and distribution of vegetation. Thus, downstream consequences can be expected as predatory fish with a role in eutrophication mitigation are negatively affected by a low water-quality. Equally, eutrophication can have negative effects on vegetation-dependent primary production, as well as food web dynamics. The demonstrated spatial responses of the species to the above-mentioned human pressures demon-strate the need of placing management actions into spatial context when trying to decide on the best course of action. Furthermore, the incorporation of human pressures allowed an evaluation of ecological and socio-economic benefits of different management actions, which was combined with an evaluation study carried out in Sweden, Lithuania and Finland regarding the population’s willingness to pay for changes in the range of the presented scenarios.

BALTIC COMPASS (BONUS)Central to the project BALTIC COMPASS was the aim to contribute towards a reduction of eutrophication by fostering win-win solutions for the agri-cultural, municipality and environmental sectors. Although the final report has not yet been published, the planned scenarios within this project are supposed to comprise four decision support scenarios for management of nutrient reduction objectives on river basins as high-risk target areas in terms of agricultural nutrient loading. Modelling included agricultural nutrient run-off assessment, optimized for each problem issue (e.g. effects of climate change or agricultural intensification). Potential future trends for nutrient loads in the Baltic Sea have been evaluated under consideration of agricultural practices, policy measures and environmental directives. Stakeholder input and global/EU-trends have also been included in this rather interactive pro-cess. Preliminary results indicate considerable problems with achieving reduced nutrient leaching close to what stakeholders in an interactive experi-

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ment were aiming for, unless changes in agricultural practices are implemented.BERAS implementation (Baltic Sea Programme 2007-2013)The BERAS implementation project is concerned with assessing the environ-mental, economic and social impacts that conversion to Ecological Recycling Agriculture (ERA) would have. The (trend)-scenarios pose an evaluation of the conversion process from standard into ERA farms, as well as the imple-mentation of the process in rural development with the aim to create recom-mendations for the Common Agricultural Policy (CAP). Two agricultural scenarios (from BERAS 2006 report) comprised BAU, which assumes that Baltic countries and Poland convert to Swedish and Finnish practices, and ERA, in which the whole Baltic drainage area converts to the ERA practice. The results were a 58 per cent nitrogen surplus increase, which corresponds to an increasing nitrogen load in the Baltic Sea, for the first and a 47 per cent nitrogen surplus reduction for the latter compared to today’s agricultural situation. Four food basket scenarios (different combinations of food con-sumption profiles, agricultural production systems, and food processing and transportation systems) that dealt with global warming, nitrogen surplus and primary energy consumption suggest that ERA, together with local processing and transport, would contribute significantly less to global warming via CO2 emissions.

MAFIA (Danish Strategic research council)The MAFIA project is about integrated management of agriculture, fishery, environment and economy. For its interdisciplinary approach it used the con-cept and framework of the BNI (Baltic Nest Institute) model for integrated economic-ecological modelling. The model incorporates nutrient flow from land to sea, internal nutrient dynamics, fish stock dynamics, as well as eco-nomic cost-minimization. Central to the work is also the role and cycling of dissolved organic matter (DOM) and nutrient retention in soil water, ground water and surface water. Fisheries and food web models were coupled for eco-logicalmodellingofdifferentecosystemcondition;cost-effectivenessandeffi-ciency of measures in agriculture, forestry, industry and transports in com-bating nutrient excess were evaluated in accordance with objectives in directives such as the Water Framework Directive (WFD) and Marine Strategy Framework Directive (MSFD).

Maria Granberg (SEPA)This study is not a scenario as such but explores how measures that are aimed at improving hypoxia could lead to the circulation of so far latent hazardous substances. These substances are found in the sediments and could find their way back into the water through disturbance of the ground by burrowing invading polychaetes, which would be able to thrive in the improved water conditions. While the introduction of oxygenation alone did not lead to the release of hazardous substances, caution should be applied when aiming to restore eutrophicated aquatic environments. No models were used for this study.

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SummaryTo summarize, most of the above-mentioned studies and scenarios deal with the effects of eutrophication, or at least water quality in connection with eutrophication in the Baltic Sea. It is a matter of concern for the surrounding countries whose inhabitants, according to surveys by PREHAB and BalticSun, are to varying degrees willing to pay for the improvement of water quality - now and in the future.

Despite the obvious connectedness of the topic area of studies, few references have been made between studies. They were carried out separately by different units, though networking between certain groups could have been beneficial by using one study’s output as input to another study. By looking at input/driver and output categories in the different studies one can observe a number of potential crossovers between studies. After all, the extent to which scenarios or even trends are meaningful and credible depends also on their coherence with other development. Linking scenarios with other regional or larger, global trends and storylines can be quite powerful as well, but this was done only on a few occasions by downscaling IPCC SRES scenarios as mentioned previously. Furthermore, through the lack of collaboration opportunitiesmayhavebeenmissedtoincreaseresourceefficiency(parti-cularly within the BONUS projects).

Benefits at risk: As stated by many of the above-mentioned projects there are two main interacting drivers that will affect services and goods provided by the Baltic Sea: climate change and eutrophication. The effects of the latter are on the whole predicted to be intensified by the former, and while some fish species might benefit from warmer sea surface temperatures and provide higher fishery yields, many other fish and plant species will be negatively influenced by climate change. Lower salinity through increased run off and high nutrient loads leading to increased water turbidity will pose challenges to marine flora and fauna. Financial benefits from coastal tourism might be in danger due to increased algae blooms and the general value of the Baltic Sea for recreational purposes is at risk.

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3. Global storylinesThe scenarios described in the previous section rarely consider global drivers besides the climate effect. Furthermore, few included any kind of narrative (storyline), global or regional, in reasoning about why the different changes would occur (e.g. changes in diet). This section will therefore describe two global storylines and their possible effect on the Baltic Sea region.

The main drivers regarding the future state of the Baltic Sea are climate, agricultural production, fishing, and transportation. Most of these are signifi-cantly affected by global trends. For example, future agricultural production around the Baltic Sea depends on matters such as global population, demand for bio-crops, human diets, climate and other drivers that policy makers of the Baltic States have none or little control over. Some assumptions concerning possible future development of crucial global drivers have to be made in order to develop different possible scenarios for the Baltic Sea region. For this reason the following two global storylines have been used and downscaled to the Baltic Sea region:• An overexploited world• A world in balance

The overexploited world can be regarded as a worst-case global storyline, while A world in balance can be regarded as a best-case storyline. By choosing these two extremes one is able to identify an interval between the worst-case and the best-case future, within which management need to be prepared to operate.

These two storylines are based on the storylines from the reports “Five scenarios for 2050: Conditions for agriculture and land use” by Öborn et al. (2011) and Agrimonde’s “Scenarios and challenges for feeding the world in 2050” (2009). The names are directly taken from two of the scenarios in the former study. The reason for basing the global storylines on these studies is that they have a focus on agriculture, which is the main driver behind the nutrient load to the Baltic Sea, and that they describe the effect on a European scale of these two storylines. Furthermore, both studies have the year 2050 as the end date for their scenarios, which corresponds to the temporal scale of the scenarios used within the BalticSTERN cost-benefit analysis. The reason why only two was chosen were partly because Agrimonde only developed two scenarios (Agrimonde 1 & Agrimonde GO), but also that of the five scenarios developed by Future Agriculture these two represented significant differences regarding agricultural production. The Agrimonde GO scenario corresponds (i.e. is very similar to) the Overexploited world scenario de-scribed by Öborn et al. (2011), while the Agrimonde 1 scenario corresponds (i.e. is very similar to) A world in balance scenario. Whenever there were inconsistencies between these two, this paper based the storyline on the one that seemed most relevant for this region. In this paper these global storylines are downscaled to the Baltic region, describing what would be the likely outcome in this region if these global changes occur.

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An overexploited worldThis global storyline depicts a rather pessimistic view of the future, including severe climate changes (3-4 degrees Celsius), increase in global population to about eleven billion by the year 2050, weakened climate and environmental policies, increased trade and lower energy prices compared to the world in balance scenario. Furthermore, it is a world still dominated by the West and with great poverty in low-income countries. The energy use is high and based on oil, coal and biofuels. There is a scarcity of land for agriculture, which makes it important to maintain the available agricultural land. Due to climate effects the European agricultural production is relocating towards the north and east. There is an industrialisation of agriculture leading to large and specialized farms, and large multinational corporations increasing their influence in the agricultural food value chain. The objective of innovations in the agricultural sector is primarily to increase yields, and agricultural yields have increased faster making it possible to satisfy both food and biofuel needs. Urbanisation is rapid and, as a consequence, the understanding of agriculture is reduced in society. The availability of phosphorus to the agri-cultural sector has decreased, and the price of this resource has therefore increased. A high economic growth has resulted in an explosion of the energy demand. This demand is satisfied above all by fossil fuels (including coal), even though the use of biofuels is increasing and renewable energies account for a total of 10 per cent of the energy consumed in 2050.

In this scenario, citizens trust in science to control sanitary and environ-mental risks. Public action is generally reactive, whether it concerns nutrition, theenvironment,orenergy.Theonlyreasontoencourageenergyefficiencygains is to cope with the scarcity of fossil fuels.

The Baltic Sea region in an overexploited world The increased population and reduction of agricultural land and production in other parts of the world (as an effect of the increased climate changes) generates a large pressure on increasing the supply of agricultural products in the Baltic Sea region. This implies an increase in agricultural land and pro-duction characterised by large farms and a dependence on artificial fertilizers, especially in the East-European countries. This will in turn contribute to a strong economic growth in the region. Even though the consumption of animal- and plant-based food is unchanged in the region, the demand from other parts of the world favours animal production over plant-based production, and as export is important, this affects production in the region. The agri-cultural policies of the European Union are characterized by regional protec-tionism, in which the EU Common Agricultural Policy (CAP) plays a major role in protecting the agricultural sector by providing subsidies. The popula-tion of the region will remain at about the same level as at present, but in the eastern countries the urbanisation have increased due to the shift from small to large sized farms.

In the BONUS funded ECOSUPPORT project the Business-As-Usual scenario is very similar to the overexploited world scenario. In this scenario BAU development was assumed for agriculture and cod fishing, in combina-

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tion with climate change (emission scenario A1B (of IPCC), a scenario which projects an annual mean around 2 degrees surface water increase in the central Baltic Sea by the end of 2100). In the model simulations of this scenario, the continuous increase of nutrient loads from the catchment caused a further enhancement of today’s deep-water anoxic areas in associa-tion with substantial summer algal blooms. These symptoms of eutrophica-tion, together with the higher cod fishing, project a future cod stock that is close to extinction.

A world in balance In contrast to An overexploited world, this global storyline represents a more optimistic view on the future, with limited climate change (1-2 degrees Celsius), and a population of eight billion. Environmental policies are strong and there is public awareness of environmental challenges. In this scenario there has occurred a shift in human values and consumption patterns. The global distribution of resources is more equal compared to today, and strong global agreements are in place. Furthermore, this storyline is characterised by a rapid development of farming, recycling and energy technology.

Production technologies are based on ecological intensification, making it possible to maintain or even increase yields, while strongly limiting the dependence on fossil fuels and the use of other agricultural inputs. Conse-quently the impacts of agricultural activities on ecosystems in this scenario are less. Although, the cultivated area has increased in comparison to An overexploited world, this is largely offset by the reduction of pastures. How-ever, in the Overexploited world yields per hectare increased owing to produc-tion technologies that made it possible to substitute labour for capital and to substantially increase production per hectare.Trade in agricultural products is strongly encouraged, and the direct support for production is therefore destined to disappear. However, the liberalisation of trade has not been accompanied by less government intervention, but the objective of this intervention has shifted from emphasises on economic growth towards more of environmental protection. Public intervention is decisive and proactive, and aimed at regional develop-ment, protection of ecosystems, and climate change adaption and mitigation. Strong incentives are provided, through national and international frame-work policies for public and private research, to make this transition occur. Furthermore, the power of agricultural organisations has been counteracted by environmental NGO’s in rich countries. A variety of actors co-exist in the agricultural food value chain. Major changes in diet, linked to environmental and above all nutritional con-cerns have occurred, with the struggle against obesity being a key objective. Citizens are aware of environmental protection as a priority, and this is reflected in their consumption behaviours. This has also influenced political priorities.

The struggle against climate change is a priority, and massive investments in the development of new energy sources have made it possible to limit greenhouse gas emissions.

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The agricultural part of this scenario is driven by three main changes: the reductionofexcessivefoodconsumptionandwaste;thedevelopmentofanecologicallyintensiveagronomy;andthesecurityofinternationaltradeinagricultural and agri-food products.

The Baltic Sea region in a balanced worldThe present waste of food at the retail and consumption level has decreased substantially in the region, thanks to policies and public awareness. Agri-cultural production in the Baltic Region has increased also in this scenario, but to a smaller degree than in the Overexploited world scenario. However, the characteristics of this production differ from the one in the Overexploited world. Farms in the region are smaller and more diverse, and the load of nutrients to the Baltic Sea has decreased due to a successful implementation of abatement measures. The production of animal products has decreased due to changes in values and eating habits. While the consumption of pork and poultry has decreased, the consumption of fish (especially farmed fish) has increased in the region. An increase of energy prices has created incentives to better utilise scarce resources, including fertilizers, and to move towards technological improvements in the energy and agricultural sectors. EU’s Common Agricultural Policy (CAP) (see description in BG Paper Manage-ment frameworks), has been reformed so that it’s focus have moved from direct payments, aimed at protecting the competiveness of EU farmers, towards financing the agricultural practices beneficial for the climate and the environment.

In the BONUS funded ECOSUPPORT project the BSAP scenario in combination with low fishing is very similar to the World in balance scenario. In the best-case scenario an agriculture that reduced nutrient load emissions according to BSAP targets, as well as cod fishing following the EU cod recovery plan with a low fishing mortality, were assumed in combination with the same climate change (emission scenario A1B) as in the worst-case scenario. The reason for using the same climate scenario is that the uncertainties in the global climate models are higher than the differences in the emission scenarios of IPCC (Meier et al., 2012). An ensemble of climate models is needed as the outputofasingleclimatemodelisnotsufficienttopredicttheeffectoffutureclimate on the relevant aspects. In the model simulations a decrease in nutrient loads followed the BSAP implementation, and led to an improvement of present deep water anoxic areas in association with summer algal blooms, which did not worsen. These improvements, together with the lower cod fishing, projected a cod stock which is higher than today but constrained at the end of the century by the projected decrease in salinity affecting the cod recruitment success.

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4. WWF scenarios for the Baltic SeaIn the WWF report “Counter currents: scenarios for the Baltic Sea towards 2030” (2012) four different scenarios are developed by using the participative approach, in which stakeholders (representing businesses, academics, deci-sion makers and NGO’s) came together in a workshop and discussed the possible futures of the Baltic Sea in terms of certain and uncertain trends.

The participants identified the following trends affecting the state of the Baltic Sea to be certain:• Maritimespatialplanningmorewidelyapplied.• Increasedglobaldemandforenergy.• IncreasedshippingandmarinetransportintheBalticSea.• Increaseddemandforfishandseafood.• Intensifiedagriculture.• IncreasedinfrastructureintheBalticSea.• Increasedcoastalactivities.I•mprovedwastewatertreatmentandwastemanagement.• IncreasedinteractionbetweenRussiaandEU.• Increasedimpactsofclimatechange.

The uncertain trends identified by the participants were:Increased use of sea resources: uncertainty with regard to whether this use is sustainable or not.• Shiftinthedemandforrenewableenergy:uncertaintywithregardto

whether the supply of these renewable energies is sustainable or not, and whether it is accompanied by a reduced or increased demand for non- renewables.

• Changingrateofmaritimeaccidents:uncertaintywithregardtothe environmental impact of these accidents.

• Changeinenvironmentalawarenessandengagement:uncertaintywith regard to whether it is a decrease or an increase.

• ImpactsonBalticSeaecosystemhealth:uncertaintywithregardto whether it is a continuous slow deterioration, sudden ecosystem collapse or a gradually improvement and recovery.

• Shiftintheeconomicparadigm:uncertaintywithregardtowhetheritshifts towards a sustainable economic development or Business-As-Usual.

• Moresustainableindustry:uncertaintywithregardtowhethertheBalticindustry becomes sustainable, or if the industrial development is fragmented due to clutter and confusion.

Two major strategic uncertainties identified by the participants of the work-shop were governance (integrated or fragmented) and ecological footprints (high or low). These were deemed by the authors of the report to be of the highest strategic importance in term of their influence of the usage of, and impacts on, the Baltic Sea.

An exploration of the trends and uncertainties identified at the workshop enabled a structure for exploring the directions in which the Baltic Sea could evolve. The following four possible future scenarios describing the state of the Baltic Sea in 2030 subsequently emerged:

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• Clear waters ahead: with low ecological footprints in combination with strong and integrated governance, this scenario clearly describes an optimistic future of the Baltic Sea in 2030. The implementations of policies aimed at restoring the Baltic Sea (e.g. BSAP, MSFD, CFP) have been successful and led to an improvement of its state.

• Dangerous currents: With high ecological footprints and strong and inte-grated governance, this scenario describes a future Baltic Sea characterised by cooperation but with a focus on short-term economic prosperity where the environmental problems of the Baltic Sea are not prioritized by neither citizens nor governments.

• Islands in the stream: With low ecological footprints but fragmented and weak governance this scenario describes a future in which people and companies have taken action to improve the state of the Baltic Sea while the governments have lost the will to take cooperate and take actions.

• Shipwrecked: With high ecological footprints and fragmented and weak governance, this scenario describes a pessimistic future where the environ-mental decline of the Baltic Sea has accelerated due to the focus on short-term economic profits and lack of governmental cooperation and actions.

These scenarios are useful in that they can prepare policymakers for different future outcomes, but they can also be used to determine a strategy working towards a specific desired future.

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5. Scenarios used within the BalticSteRn researchWithin the BalticSTERN research, scenarios were used to describe the future state of the Baltic Sea under the different policy scenarios.

The BalticSUN study elicited willingness to pay for two eutrophication scenariosrelatedtoreachingtheBalticSeaActionPlan’s(BSAP;HELCOM,2007) nutrient reduction targets. A business as usual (BAU) eutrophication scenario (non-action scenario) was developed and described, the expected development of nutrient loads and concentrations in the Sea in 2050 if no additional abatement actions are undertaken. The BAU scenario was then compared with two different policy scenarios, one scenario where the BSAP-targets regarding nutrient loads were fulfilled, and one scenario where the nutrient loads targets were met to 50 percent. The description was based on the expected levels of five characteristics in each quality class: level of water clarity, extent of blue-green algal blooms, the state of underwater meadows, fish species composition and oxygen conditions in deep-sea regions.

The main purpose of BalticSTERN scenarios was to come up with a simulation model that can be used in a cost-benefit analysis regarding mitigation of Baltic Sea eutrophication. Models relating water and nutrient exchange across the seven basins, changes for both short and long-term developments and a single indicator value was used as an aggregate of multidimensional outputs from 3D models describing the state of the Baltic Sea. Subsequently the 50 per cent and full BSAP implementation was applied and their effect on water quality across the Baltic Sea was illustrated. Climate change was not included in these scenarios since it was assumed that these effects would not have an impact on the state of the Baltic Sea by 2050.

Since it takes time for abatement measures to have an impact on the environmental state of the Baltic Sea, descriptions need to be made regarding the timing and extent of improvements generated by the BSAP. As described in the BG paper Benefits of mitigation scenarios regarding the future state of the Baltic Sea, with and without BSAP, were necessary inputs to the BalticSUN valuation study. Scenarios were also required for the cost estimates, since possible future changes of the pressures and drivers behind eutrophication have effects on the abatement measures required to reach the targeted nutrient load. For example, if it is believed that agricultural production will increase, it is likely that more abatement measures need to be taken compared to if it is assumed to stay the same.

With regard to the scenarios developed by WWF (2012) the successful implementation of BSAP most likely reflects the scenario Clear waters ahead described in Chapter 4, since it represents governance that is integrated rather than fragmented and a small ecological footprint. in that the state of the Baltic Sea is recovering with regard to eutrophication. The Business-As-Usual scenario can be compared to the Shipwrecked scenario in that integrated governance, in terms of BSAP, has not been realized and that the ecological footprint with regard to eutrophication remains large.

The agricultural scenario used within the BalticSTERN research was based on Agmemod projections for trends within the Baltic region agricultural

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production (use of fertilizers, land use, etc) until 2020 (Agmemod Partner-ship, 2010). These trends were thereafter extrapolated until 2050. This agri-cultural scenario can be regarded as reflecting the optimistic World in balance of the global storylines, since it does not foresee any large increase of the nutrient load from the agricultural sector.

As is evident from above, the global development related to the two scenarios (with and without BSAP nutrient target fulfilment) could be regarded as rather optimistic about the future development. An expansion of the agricultural sector, in line with the pessimistic scenario of an Overex-ploited world, would imply that more measures are needed in order to meet the BSAP targets, thereby raising the total cost of this in a cost-benefit analysis. However, such a development would also lead to a worse state of the Baltic Sea if the BSAP were not reached compared to the one illustrated to the respondents in the willingness-to-pay study described in BG Paper Benefits of mitigation. Therefore, not only the costs, but also the benefits, are likely to be larger in a pessimistic scenario, making it hard to say anything about the relationship between cost and benefits. These scenarios do not include any climate changes, which according to the ECOSUPPORT project most likely will lead to a worsening of the Baltic Sea eutrophication.

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6. Conclusions and discussionThe development of scenarios for the Baltic Sea is vital when conducting cost-benefit analysis since the way the future evolves will affect the measures needed in order to reach the BSAP targets, as well as the benefits obtained by reaching them.

As is clear from above a significant number of scenarios for the Baltic Sea exist. However, there is a lack of coordination and communication in the development of these and more exchange regarding e.g. input scenarios could have been beneficial. Most Baltic Sea scenarios lack a connection to global scenarios (with the exception of climate change), even though it is clear that global drivers play a significant role in determining the impacts on the environmental state of the Baltic Sea. Most scenarios developed within academics with connection to the environmental state of the Baltic Sea are based on models linking different drivers and pressures and states. Most of these academic scenarios do not involve a participatory approach, which might be explained by the fact that they are model-based and mainly focus on natural, rather than political and economical, parameters.

The WWF report Counter Currents: scenarios for the Baltic Sea towards 2030 (2012), is an example of scenarios in the shape of narratives, which are

developed by different stakeholders through the participatory approach. These scenarios strength lies in that they involve stakeholders and are capable of describing a wide range of possible futures. However, since they are rarely based on models, they often fall short in describing in detail how the environ-mental state might be in the different scenarios. For example, while the WWF report describes different outcomes regarding ecological footprints and governance in qualitative terms in their four scenarios, model based scenarios (such as e.g. ECOSUPPORT) often calculate the change in environmental state in a more detailed way (e.g. in terms of fish stock size, primary pro-duction, number of oil spills).

By describing the two most extreme cases (i.e. an overexploited world and a world in balance) an interval is illustrated, within which a range of possible events can occur. Regardless of what future is most likely, policy makers must be aware of possible ways the future may evolve in order to be prepared and to be able to develop strategies flexible enough to handle future changes.

It needs to be emphasised that the scenarios are only potential pathways. Due to the long ecosystem response character of the Baltic, even the very positive and desirable storylines/scenarios project that it will take time before the water quality of the Baltic will improve substantially. The scenarios from the ECOSUPPORT project, project that even with full implementation of the BSAP and the EU cod recovery plan there may still be non-linear changes of fish and zooplankton species, which might cause large-scale regime shifts. This illustrates that even in conditions with full policy implementation, an adaptive management approach is required to prevent undesirable regime shifts. Furthermore, many ecosystem models are calibrated during recent times and therefore their responses to future conditions, which may never have been observed before, are highly uncertain and can therefore only

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provide potential pathways. However, the combination of adaptive manage-ment and the use of such scenario exercises to experiment with certain management options could be a powerful approach to be better prepared for an uncertain future.

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ReferencesAgmemod Partnership. 2010. http://www.tnet.teagasc.ie/agmemod/, viewed 30.3.2010

Agrimonde. 2009. Scenarios and Challenges for Feeding the World in 2050. Summary Report

HELCOM, 2007. (Helsinki Commission) Helcom Baltic Sea Action Plan. Adopted on 15 November 2007 in Krakow, Poland by the HELCOM Extra-ordinary Ministerial Meeting. Helcom, Helsinki. Available at: www.helcom.fi

Rotmans, J., Anastasi, C., van Asselt, M.B.A., Greeuw, S., Mellors, J., Peters, S., Rothman, D. 2000. VISIONS for a Sustainable Europe Futures 32, 809-831.

WWF. 2012. Counter currents: scenarios for the Baltic Sea towards 2030.

Öborn, I., Magnusson, U., Bengtsson, J., Vrede, K., Fahlbeck, E., Steen Jensen, E., Westin, C., Jansson, T., Hedenus, F., Lindholm-Schulz, H., Stenström, M., Jansson, B., Rydhmer, L. 2011. Five Scenarios for 2050 – Conditions for Agri-culture and land use. Uppsala, Swedish University of Agricultural Sciences.