Lors de catastrophes pétrolières, l’utilisation de dispersant est une stratégie de lutte qui permet le transfert de la nappe de pétrole de la surface vers la colonne d’eau, sous forme de gouttelettes d’hydrocarbure. En milieu côtier, la dispersion d’une nappe de pétrole est une mesure controversée car la faible profondeur de la colonne d’eau ne permet pas une dissémination rapide des gouttelettes d’hydrocarbure et expose ainsi les écosystèmes aquatiques à de fortes concentrations de contaminant. Afin d’évaluer la toxicité de l’application de dispersant en zones côtières, une approche expérimentale a été menée chez des juvéniles de Liza sp. en considérant trois scenarii : (i) la dispersion mécanique de la nappe simulant une dispersion naturelle due aux conditions météorologiques ; (ii) la dispersion chimique de la nappe simulant l’application de dispersant ; (iii) l’absence de dispersion de la nappe simulant son confinement avant récupération. La toxicité de chaque condition a été évaluée au travers d’une mesure de la mortalité sur un groupe d’individu, par l’estimation des performances de nage et de la capacité métabolique au niveau de l’organisme, et par une approche multimarqueur au niveau de l’organe.La comparaison entre une nappe de pétrole non dispersée et une nappe de pétrole dispersée chimiquement montre que l’application de dispersant entraine une augmentation des phénomènes de mortalité et une diminution, au niveau hépatique et branchial, des capacités de défense contre les xénobiotiques. A l’inverse, la comparaison entre une nappe de pétrole dispersée mécaniquement et chimiquement montre que, lorsque l’agitation de la mer est importante, l’application de dispersant ne semble pas potentialiser la toxicité du pétrole.Ces résultats suggèrent que (i) la récupération de la nappe de pétrole devrait être considérée comme une technique de lutte prioritaire sur l’utilisation de dispersant ; (ii) l’application de dispersant pourrait être considérée lors de conditions météorologique appropriées. / Dispersant application is an oil spill response technique which accelerates the dispersion of petroleum from the sea surface into the water column by inducing the formation of oil droplets. In coastal areas this response technique is controversial since the low water depth reduces the dissemination of oil droplets and by the way increases the exposure of aquatic ecosystems to petroleum. To evaluate the toxicity of dispersant application in nearshore areas, an experimental approach was conducted. Juvenile of Liza sp. were exposed to three scenarios of contamination: (i) to chemically dispersed oil - simulating, in vivo, dispersant application ; (ii) to mechanically dispersed oil - simulating, in vivo, natural dispersion due to meteorological conditions ; (iii) to an undispersed oil slick simulating, in vivo, oil slick confinement as a response technique. Toxicity of each condition of exposure was evaluated through the mortality upon a group of individuals, through the swimming performance and the metabolic scope at the organism level, and through the measurement of biomarkers at the organ level.Comparison between an undispersed oil slick and a chemically dispersed oil slick shows that dispersant application induces an increase of the mortality and decreases the ability of the animal to cope with environmental contaminants (deduced from gill and liver total glutathione rate). Conversely, comparison between both a mechanically and a chemically dispersed oil slick, suggests that, when sea water is under mixing processes, dispersant application does not enhance petroleum toxicity. Taken together these results suggest that (i) an oil slick must not be dispersed when recovery can be conducted; (ii) dispersant application could be considered as a response technique when meteorological conditions are appropriated.

Dricksvatten är en livsviktig resurs. Att varje hushåll får dricksvatten ser vi idag ofta som självklart, dock har vatten som dricksvattenresurs en begränsning inte minst i kommuner utmed Sveriges kust. I dessa kustnära kommuner finns mängder av fritidsbostäder som allt fler ägare väljer att utnyttja som permanentbostäder. Kustkommunerna, som tidigare inte valt att bygga ut vatten- och avloppsnätet till dessa bostadsområden, har inte haft möjlighet att hinna anpassa utbyggnaden efter det nya befolkningsantalet. Istället tas dricksvattenförsörjningen från grundvattnet via enskilda bergborrade brunnar. Den snabba inflyttningen ökar därmed uttaget av grundvatten från brunnar som kanske inte har den kapacitet som krävs för att försörja allt fler permanentbostäder. Denna studie är begränsad till tre kommuner längs Sveriges östkust, Norrtälje-, Tyresö- och Oskarshamns kommun. Grundvattenbildningen och magasineringen av grundvattnet i dessa områden är mycket begränsad på grund av den geologiska bildningen, vilket hotar grundvattennivåerna. Därav är det viktigt för kommunerna att bevara de täkter som finns i kommunen. För att säkra kommunernas grundvattenförekomster kan vattenskyddsområden införas och gamla vattenskyddsområden kompletteras. De tre kommunerna arbetar alla för en hållbar dricksvattenförsörjning. Ingen av dem når dock upp till den önskvärda nivån av hållbarhet. Både Norrtälje- och Oskarshamns kommun har vattenskyddsområden för sina betydande vattentäkter. Tyresö kommun har dock inga vattenskyddsområden, de har istället naturreservat och nationalparker som även skyddar vattnet i kommunen. Dock löser inte ett vattenskyddsområde eller skydd av annat slag problemet med ett överutnyttjat grundvattenuttag. Där krävs metoder för att se till att uttagen är mindre än nybildningen av grundvatten. En sådan metod är beräkning av grundvattenbalansen i området, som visar när grundvattenbildningen sker och när uttagen är som störst under en viss tidsperiod. Därefter kan då uttagen planeras utefter vattentäktens kapacitet. En annan lösning är att bidra till en ökad grundvattenbildning via konstgjord väg. Det kan ske via till exempel sprinklers eller ytvattendammar, där dessa kan tillföra vatten till grundvattnet och därmet kan uttag göras utefter den nya grundvattenbildningens förmåga. Utöver dessa förslag krävs att kommunernas nuvarande råd och riktlinjer för enskild vattenförsörjning skärps till lagar och regler. I detaljplanen kan även styrmedel läggas in så som antal brunnar, brunnsdjup och maximalt uttag för kommunen. Detta blir då juridiskt bindande och betydande viktigt för den enskilda vattenförsörjningen och för hållbarhetsarbetet. Det finns därav många åtgärder som måste vidtas snarast för kommunerna för att de ska kunna uppnå miljömålet “Grundvatten av god kvalitet”, vilket nu ser ouppnåeligt ut för sin tidsgräns till 2020. / Drinking water is a vital resource that often is taken for granted. This is a problem not least in municipalities along the coast of Sweden. This due to the salty sea water that pushes towards land. It is very popular in today's society to live in coastal areas. There are both many vacation houses but also a lot of permanent livings. It is common these days that people choose to turn their vacation house into permanent living house and that has its effects on the drinking water resource. The houses of coastal areas are getting their drinking water from individual wells instead of the communal water. The main problem for the drinking water in the coastal areas are therefore the quality of the groundwater. There are risk for infiltration of salt water to the ground water. When the salt reaches the ground water, it will end up in the well and reduce the quality. That makes it a huge problem in these areas. Not to mention that the groundwater reservoirs are very limited in these territories, which limits the groundwater as a drinking water resource at the coast. To exemplify the facts, this study will cover the information for three different municipalities along the coast of Sweden. These are Norrtälje, Tyresö and Oskarsham. The drinking water supply in these three municipalities are similar but one thing that is different is the plan for sustainable drinking water supplies. Building and storage of groundwater in these areas is very limited due to the geological formation, which threatens groundwater levels. In order to secure the municipalities groundwater reservoirs, water protection areas can be made. The three municipalities all work for sustainable drinking water supply, but none of them manage to reach the goal “sustainable”. Both Norrtälje and Oskarshamn has water protection areas for its significant water resources. However, Tyresö has no water conservation areas, but they have nature reserves and national parks instead, that also protect the water. A water protection does not solve the problem of an over-exploited groundwater outlet. There are methods required to ensure that the outlets are smaller than the formation of groundwater. Such a method is the calculation of the groundwater balance in the area, which shows when the groundwater formation occurs and when the outlet is the largest during a certain period of time. After that, the outlet can be planned according to the capacity of the water source. Another solution is to contribute to increased groundwater formation through artificial infiltration. This can be done by sprinklers or surface water ponds, where they can supply water to the groundwater, and the outlet can be taken along the new groundwater formation. In addition to these proposals, the current advices and guidelines for individual water supply need to be tightened up and be replaced with laws and regulations. There are many moves that must be taken as soon as possible for the municipalities to achieve the goal "Grundvatten av god kvalitet", which is now unreachable for its time limit by 2020.

Coastal areas of Southeast Asia are progressively threatened by flooding as a consequence of more frequent precipitation extremes and rising sea levels. Especially urban areas are affected by flood risk which is additionally increased by surface subsidence related to building activities and groundwater extraction. However, the severity of subsidence as well as its triggers and environmental interrelations are only little understood. This study measures surface subsidence for Hue city by using persistent scatterer radar interferometry (PS-InSAR). A series of 53 images acquired by the Sentinel-1 radar satellite between 2018 and 2019 was analyzed to reliably retrieve surface changes at the millimeter scale. The overall displacement ranges between -25 and +10 millimeters per year. Its spatial distribution was then compared to the extent of different soil types in the study area to conduct an analysis of variance (ANOVA). The results confirmed a significant difference between the soil types with Plinthic Acrisols as the soil type having the largest negative average surface velocity. Possible triggers are the intrusion of slack water from the surrounding rice cultivation areas and construction activities which lead to increasing weight and soil compaction. The findings shall raise awareness for the topic and underline the demand for further research. / Mưa lớn và nước biển dâng là những nguyên nhân gây lũ lụt ngày càng nghiêm trọng ở các khu vực ven biển Đông Nam Á. Đặc biệt việc gia tăng công trình xây dựng và khai thác nước ngầm gây sụt lún bề mặt dẫn đến ngập lụt ở các vùng đô thị. Tuy nhiên, các nghiên cứu về mối tương quan giữa sụt lún bề mặt với các hiện tượng môi trường chưa được chú trọng nhiều. Trong nghiên cứu này, độ lún bề mặt của thành phố Hue được đo bằng phương pháp giao thoa radar tán xạ liên tục (PS-InSAR). Phân tích 53 ảnh vệ tinh Sentinel-1 từ năm 2018-2019 cho thấy sự thay đổi tổng thể bề mặt dao động từ -25mm đến 10mm mỗi năm. Phân tích phương sai (ANOVA) cho thấy sự thay đổi bề mặt khác nhau tùy từng loại đất, trong đó đất đỏ vàng (Plinthic Acrisols) có tốc độ sụt lún trung bình cao nhất. Các tác nhân có thể là do sự xâm nhập của nước từ các vùng trồng lúa xung quanh và các hoạt động xây dựng dẫn đến tăng trọng lượng và nén đất. Những phát hiện này là cơ hội nâng cao nhận thức về sự sụt lún bề mặt và cần được nghiên cứu thêm.

Les zones côtières ont depuis longtemps été attractives pour leur potentiel économique, et leur intérêt touristique et résidentiel. Elles ont fait l’objet d’une implantation massive dans tous les pays du monde. Or, les littoraux sont non seulement fragilisés par cette anthropisation, mais sont également sujet à des dégradations liées au changement climatique. À l’élévation du niveau de la mer souvent mise en avant dans les médias s’ajoute l’érosion intensifiée par les tempêtes et ouragans à répétition. Alors qu’émerge depuis plusieurs années la question des déplacés environnementaux ne disposant d’aucun statut protecteur, et dont le symbole le plus extrême est la situation de certains petits États insulaires dont le territoire est menacé de disparition par la montée des eaux, la question de la gestion de cette problématique dans le respect des droits humains se pose de manière accrue. L’enjeu de ce travail, s’appuyant sur des pays au profil différent : Bangladesh, États-Unis, France, petits États insulaires (notamment les Maldives, Kiribati, Tuvalu), est de rechercher les causes profondes de cette contrainte devenue tellement intense qu’elle conduit au déplacement, pour favoriser l’adaptation sur place ou mettre en œuvre un déplacement non plus conçu comme un échec mais comme une stratégie d’adaptation. Ce changement de perspective impliquera de mobiliser des outils juridiques issus de branches variées du droit (urbanisme, assurance, responsabilité et droit humanitaire, etc.) et surtout de respecter certains principes afin d’assurer l’anticipation et l’acceptation de la démarche par les populations. Fort de l’étude de ces exemples, il s’agira d’identifier ces éléments communs tout en mettant en lumière et en tenant compte des spécificités de chaque pays, de chaque communauté. / Coastal areas have always been attractive for their economic potential and their touristic and residential interest. They have been massively settled in countries all over the world. However, while coastlines are weakened by human impact, they are also subject to degradations due to climate change. Besides the sea-level rise, often emphasized by the media, we must consider the erosion caused by storms and hurricanes. The current context is strongly marked by the question of the environmental displaced persons who do not have any status. This situation can be illustrated by the small island states whose territory is threatened by the sea-level rise. Thus, the issue of managing these problems in respect with human rights arises to an increased extent. The challenge of this work, supported by different country profiles: Bangladesh, USA, France, Small Island States (including the Maldives, Kiribati, Tuvalu), is to seek the root causes of this dilemma that has become so intense that it leads to displacement, and then to promote and facilitate adaptation in-situ or adopt new displacement policies that are no longer perceived as a failure but as an adaptation strategy towards risks. This change of perspective intends to mobilize legal tools from various branches of law (Urbanism, Insurance, Liability and humanitarian law, etc.). It also intends to respect principles to ensure anticipation and acceptance of the approach by the people. With the study of these examples, we must identify these commons elements and take into account the specificities of each country and each community.

<p>This thesis presents models applicable for aquatic ecosystems. Geographical Information Systems (GIS) form an important part of the thesis. The dynamic mass balance models focus on nutrient fluxes, biotic/abiotic interactions and operate on different temporal and spatial scales (site, local, regional and international). The relevance and role of scale in mass balance modelling is a focal point of the thesis.</p><p>A mesocosm experiment was used to construct a model to estimate the nutrient load of phosphorus and nitrogen from net cage fish farming (i.e., the site scale). The model was used to estimate what feeding conditions that are required for a sustainable aquaculture scenario, i.e., a zero nutrient load situation (a linkage between the site scale and the regional scale). </p><p>A dynamic model was constructed for suspended particulate matter (SPM) and sedimentation in coastal areas (i.e., the local scale) with different morphometric characteristics and distances to the Sea. The results demonstrate that the conditions in the Sea (the regional and international scale) are of fundamental importance, also for the most enclosed coastal areas.</p><p>A foodweb model for lakes was transformed and recalibrated for Baltic Sea conditions (i.e., the international scale). The model also includes a mass balance model for phosphorus and accounts for key environmental factors that regulate the presuppositions for production and biomasses of key functional groups of organisms. The potential use of the new model for setting fish quotas of cod was examined.</p><p>For the intermittent (i.e., regional) scale, topographically complex areas can be difficult to define and model. Therefore, an attempt was made to construct a waterscape subbasin identification program (WASUBI). The method was tested for the Finnish Archipelago Sea and the Okavango Delta in Botswana. A comparison to results from a semi-random delineation method showed that more enclosed basins was created with the WASUBI method.</p>

This thesis presents models applicable for aquatic ecosystems. Geographical Information Systems (GIS) form an important part of the thesis. The dynamic mass balance models focus on nutrient fluxes, biotic/abiotic interactions and operate on different temporal and spatial scales (site, local, regional and international). The relevance and role of scale in mass balance modelling is a focal point of the thesis. A mesocosm experiment was used to construct a model to estimate the nutrient load of phosphorus and nitrogen from net cage fish farming (i.e., the site scale). The model was used to estimate what feeding conditions that are required for a sustainable aquaculture scenario, i.e., a zero nutrient load situation (a linkage between the site scale and the regional scale). A dynamic model was constructed for suspended particulate matter (SPM) and sedimentation in coastal areas (i.e., the local scale) with different morphometric characteristics and distances to the Sea. The results demonstrate that the conditions in the Sea (the regional and international scale) are of fundamental importance, also for the most enclosed coastal areas. A foodweb model for lakes was transformed and recalibrated for Baltic Sea conditions (i.e., the international scale). The model also includes a mass balance model for phosphorus and accounts for key environmental factors that regulate the presuppositions for production and biomasses of key functional groups of organisms. The potential use of the new model for setting fish quotas of cod was examined. For the intermittent (i.e., regional) scale, topographically complex areas can be difficult to define and model. Therefore, an attempt was made to construct a waterscape subbasin identification program (WASUBI). The method was tested for the Finnish Archipelago Sea and the Okavango Delta in Botswana. A comparison to results from a semi-random delineation method showed that more enclosed basins was created with the WASUBI method.

The study addresses the topics of climate adaptation and sustainability in coastal areas, using Oceanhamnen in Helsingborg as a case study. The research examines the measures taken to adapt the area to climate change and evaluates the sustainability considerations in the planning. The theoretical framework for the study is based on future scenarios assembled from international organizations and Swedish authorities. Within the study, the three different methods literature analysis, observation, and interviews are simultaneously utilized to address the research questions. The results indicate that climate adaptation measures have been taken into account based on the latest future scenarios during the planning stage of Oceanhamnen. However, future scenarios evolve over time, and this does not necessarily ensure the maintenance of the area’s climate adaptation in the future. / Studien behandlar ämnena klimatanpassning och hållbarhet inom kustområden, som ett fallstudie med Oceanhamnen i Helsingborg som utgångspunkt. Arbetet undersöker vilka åtgärder som har tagits för att klimatanpassa området och hur hållbart det har planerats. De teoretiska ramarna för studien är framtidsscenarier som har sammanställts från internationella organisationer och svenska myndigheter. Inom studien används de tre olika metoder litteratur analys, observation samt intervju parallellt för att besvara frågeställningarna. Resultatet visar att klimatanpassningsåtgärder har vidtagits med hänsyn till de senaste framtidsscenarierna under planeringsstadiet av Oceanhamnen. Dock ändras framtidsscenarierna med tid och detta behöver inte betyda att områdets klimatanpassning bibehålls i framtiden.

The purpose of this study was to determine the limiting nutrient in a set of coastal areas and estuaries in the Baltic Sea. Although the subject as been studied for several decades, no clear consensus has been reached in the scientific community as to whether primary production is limited by phosphorus or nitrogen. A total of five coastal areas, all located on the east coast of Sweden, were assessed regarding their limiting nutrient by using three methods. The first method was applying linear regression analysis on measured TP and TN concentration together with chlorophyll-a and Secchi depth. The data was collected from sampling programs stretching back to the 1970s and 80s, studying the summer period May to September for all sites but one, were the period April to October was studied. The second method calculated the TN/TP ratio during the summer period and compared it to the Redfield ratio. Thirdly, basic mass-balance calculations were carried out, with empirical data on the external loads and calibrated with the yearly average concentration in the surface water (0–10 m). From the calculations, both the annual external and internal load of TP and TN was obtained. The different TP and TN loads were likewise tested for a correlation with the measured summer chlorophyll-a concentration and Secchi depth. The results of using linear regression analysis on measured concentrations were mostly inconclusive, as the TP and TN concentrations for all sites and most years were related to each other. Consequently both nutrients often gave equal correlation coefficients. Similarly the TP and TN loads also matched each other for most sites and years, inherently obtaining the same inconclusive, but also contradictory results, as when using the measured concentrations. The TN/TP ratio indicated, for one site that it was limited by phosphorus and another site possibly nitrogen limitation. The ratio in the other sites periodically dropped between nitrogen and phosphorus limitation over the years. Thus it was difficult to draw an overall conclusion as to what nutrient was the limiting one for all the sites. However analysing the results from the individual sites showed that three of the five sites had signs of phosphorus limitation. Two factors were deemed as being the main reasons as to why the methods did not achieve more conclusive results. The first factor was the empirical data, which varied in frequency and extent over the studied time periods and between sites, making representative concentrations difficult to calculate and evaluate. The second was the matching trends between both the concentrations and the loads of TP and TN. To achieve a better result one nutrient could be increased or decreased while one remains relatively constant. The problem with such an experiment would be controlling the inflow of nutrients from the adjacent sea. / Syftet med detta projekt var att bestämma det begränsande näringsämnet för ett antal kustområden i Östersjön. Frågan huruvida fosfor eller kväve är det begränsande näringsämnet i kustområden runt Östersjön har varit omdiskuterad under flera år och undersökts vid ett flertal tillfällen. I denna studie testades tre metoder, i fem olika kustområden, med syftet att fastställa det begränsande näringsämnet. Först användes linjär regressionsanalys med uppmätta värden på TP och TN koncentrationer tillsammans med klorofyll-a och Secchidjup. Empirisk data insamlades från övervakningsprogram där prover tagits sedan 1970- och 80-talet. Medelvärden beräknades för perioden maj till september för alla områden förutom ett, där undersöktes perioden april till oktober. Sommarmedelvärdena för TN/TP kvoten analyserades också för alla områden med avseende på Redfield kvoten. Slutligen genomfördes massbalansberäkningar med data för de externa belastningarna av TP och TN, dessa beräkningar kalibrerades sedan med uppmätta värden på koncentrationen i ytvattnet (0–10 m). Utifrån beräkningarna erhölls värden på den externa och den interna belastningen. Dessa belastningar testades med linjär regression för ett samband med de uppmätta värdena på Secchidjup och klorofyll-a. Metoden att använda linjär regressionsanalys med empiriskt uppmätta koncentrationer och djup, gav generellt ett oklart resultat. Detta var en följd av att halterna av både TP och TN i regel följdes åt, vilket fick konsekvensen att korrelationskoefficienterna för TP och TN ofta var lika stora. Samma problem uppstod för regressionsanalysen med belastningarna, då även dessa ofta följde varandra, men även motsade resultatet med koncentrationerna. Analysen av TN/TP kvoten tydde på att ett område var fosforbegränsat och ett område möjligen var kvävebegränsat. För de övriga tre områdena skiftade TN/TP kvoten under åren mellan kväve- och fosforbegränsning. De oklara resultaten gjorde det svårt att dra en övergripande slutsats. Däremot vid analysen av de enskilda områdena uppvisade tre av de fem områdena tecken på fosforbegränsning, även om detta inte kunde med säkerhet fastställas. Det var huvudsakligen två faktorer vars inverkan anses ha haft stor betydelse för det oklara resultatet. Den första faktorn var uppmätt data, vars frekvens och omfattning skiljde sig avsevärt mellan år och platser. Följaktligen försvårades beräkningarna av koncentrationerna och tillförlitligheten i hur representativa värdena var. Den andra och avgörande faktorn var de matchande trenderna hos både koncentrationerna och belastningarna. För att förbättra resultatet kan ett näringsämne ändras, medan det andra näringsämnet hålls relativt konstant. Problemet med att genomföra ett sådant experiment skulle vara att kontrollera inflödet av näringsämnen från närliggande hav.

L’enjeu de cette étude est d’analyser comment le risque d’érosion côtière est appréhendé d’un point de vue juridique. Ce risque naturel se caractérise par une avancée progressive de la mer sur les terres, appelée à s’accentuer dans les prochaines décennies selon les derniers rapports scientifiques. Cependant, l’on observe que parallèlement à cela, les côtes métropolitaines accueillent une population de plus en plus grandissante ; se produit ainsi la rencontre de deux tendances antinomiques. Dès lors, l’objet de la présente étude est d’observer les conséquences juridiques résultant de cette confrontation. Par conséquent, afin de parvenir à la conciliation de ces différents enjeux, nous allons démontrer l’intérêt de faire évoluer les politiques publiques de gestion de l’érosion côtière en faveur d’une approche intégrée, selon les principes fondamentaux de la GIZC. Notre étude va ainsi proposer une traduction juridique de cette évolution. / The aim of this study is to analyze how the risk of coastal erosion is apprehended at a legal point of view. This natural risk is characterized by a gradual encroachment of the sea on land, intending to grow in the coming decades according to the latest scientific reports. However, it is observed that beside this, the metropolitan coast are home to an increasingly growing population ; so we find the meeting of two contradictory trends. Therefore, the purpose of this study is to observe the legal consequences of this confrontation. So, in order to achieve the reconciliation of these issues, we will demonstrate the importance of the development of public policies for managing coastal erosion in favor of an integrated approach, based on fundamental principles of ICZM. Our study will thus provide a legal expression of this development.

Behovet av klimatanpassning i kustområden är stort, och fortsätter öka världen över. Naturbaserade lösningar (NBS) är flexibla och multifunktionella åtgärder som samverkar med naturliga processer, vilket gör dem anpassningsbara till förändrade förhållanden, till skillnad från hårda kustskydd. Genom denna studies kvalitativa intervjuer med fyra skånska kustkommuner har förutsättningar för NBS att främja klimatanpassning visats vara på god väg. Kustkommunerna ser NBS som ett självklart förstahandsval inom kustskydd. NBS har fått större genomslag i och med ökat samarbete på lokal, regional, nationell och internationell nivå genom nätverk och projekt, vilket har möjliggjort stort utbyte av praktiska lärdomar och kunskap om NBS, naturliga processer och klimatförändringars effekt i kustområden. Samverkan är en viktig del i klimatanpassningsarbetet där samlad expertis bidrar till gemensam förståelse för NBS funktion och mervärden. Idag finns konsensus om ett naturbaserat arbetssätt, där tjänstepersoners och eldsjälars kunskap, intresse och engagemang spelar en avgörande roll för det kommunala arbetet med NBS. Deltagande i NBS-projekt ger mer praktisk erfarenhet och synliggör åtgärdernas positiva effekter, vilket i sin tur kan skapa lokala politiska incitament för att integrera och använda NBS ytterligare i klimatanpassningsarbetet. Dock påträffas flertalet svårigheter, i huvudsak gällande förlegad lagstiftning som inte är kompatibel med NBS flexibilitet, tidskrävande och komplicerade tillståndsprocesser samt frånvaron av uttalat tillvägagångssätt gällande gränsöverskridande åtgärder för hur kommuner, myndigheter samt enskilda fastighetsägare ska samarbeta och dela på ansvaret. För att kunna normalisera och skala upp implementering behöver NBS bli inkluderade som standardalternativ vid beslut om olika kustskyddsåtgärder. Svenska kustkommuner kommer behöva ta ställning och diskutera acceptansen för klimatförändringars olika grad av påverkan i kustområden, där obekväma beslut och övervägandet av andra strategier såsom förändrad markanvändning och planerad reträtt väntas bli mer påträngande. Studiens resultat kan förhoppningsvis uppmuntra naturbaserade insatser inom svenskt klimatanpassningsarbete ytterligare, för att säkerhetsställa levande kustområden där natur och samhällen kan bevaras och klimatsäkras för dagens och framtida klimatförändringar. / The need for climate adaptation in coastal areas is great, and continues to increase worldwide. Nature-based solutions (NBS) are flexible and multifunctional measures that interact with natural processes, which makes them adaptable to changing conditions, as opposed to hard coastal protection. Through this study's qualitative interviews with four southern Swedish coastal municipalities, the conditions for NBS to promote climate adaptation have been shown to be on the right track. The coastal municipalities see NBS as an obvious first choice in coastal protection. NBS have had a greater breakthrough by increased cooperation at local, regional, national and international level through networks and projects, which has enabled a great exchange of practical lessons and knowledge about NBS, natural processes and the effect of climate change in coastal areas. Collaboration is an important part of the climate adaptation work, where collective expertise contributes to a common understanding of NBS' function and co-benefits. Today, there is consensus on a nature-based approach, where the knowledge, interest and commitment of officials and champions play a crucial role in the municipal work with NBS. Participation in NBS projects provides more practical experience and highlights the positive effects of the measures, which in turn can create local political incentives to further integrate and implement NBS in climate adaptation work. However, many difficulties are encountered, mainly regarding outdated legislation that is not compatible with NBS flexibility, time-consuming and complicated permit processes, and the absence of a stated approach regarding cross-border measures for how municipalities, authorities and individual property owners should cooperate and share responsibility. To be able to normalize and scale up implementation, NBS needs to be included as a standard alternative when deciding on various coastal protection measures. Swedish coastal municipalities will need to take a stand and discuss acceptance of climate change's different level of impact in coastal areas, where uncomfortable decisions and the consideration of other strategies such as changed land-use and planned retreat are expected to become more intrusive. The results of the study can hopefully encourage nature-based initiatives in Swedish climate adaptation work further, to ensure living coastal areas where nature and communities can be preserved and climate-secured for current and future climate change.