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Carbon emission from Arctic rivers constitutes a positive feedback between the climate warming and C cycle. However, in case of rivers with extensive floodplains, the impacts of temporary water bodies and secondary channels on CO2 exchange with atmosphere, compared to the main stem and tributaries, remain strongly understudied. In order to quantify the relative role of various water bodies of the Arctic river basin in the C cycle, the hydrochemical variables and greenhouse gases GHG concentrations and fluxes were measured within the floodplain of the largest Arctic River, Ob, in its low reaches located in the permafrost zone. These included the main stem, secondary channels, tributaries and floodplain lakes sampled over a 900 km north-south transect (25,736 km2 of the main stem and adjacent floodplain area; 7893 km2 water surface) during peak of spring flood (May 2023). In addition to main stem and tributaries, providing less than a half of overall C flux, floodplain lakes and secondary channels acted as important factor of C emission from the floodplain water surfaces. Multi-parametric statistical treatment of the data suggested two main processes of C emission from the Ob River floodplain waters: terrestrial organic matter-rich flooded wetlands (fens) provided elevated pCO2, whereas the sites of possible groundwater discharge in the secondary channels decreased the CO2 fluxes due to more alkaline environments, rich in labile metals and anionic elements. Based on available high-resolution Landsat-8 images, which matched the period of field work, it was found that the total water coverage of the floodplain during spring 2023 was 30 % of overall territory, compared to 18 % during the baseflow. Based on chamber-measured CO2 fluxes (1.56 ± 0.47 g C-CO2 m−2 d−1), overall CO2 emissions during 2 months of the spring flood from the entire Lower Ob River floodplain water surfaces including the main stem amounted to 0.73 ± 0.25 Tg C. Diffuse CH4 flux represented <1 % of t

Earthworms are among the most crucial species for global food production and soil fertility. However, in soils and ecosystems that have evolved without worms, their introduction can lead to significant ecological change. Due to the eradication of soil fauna during the last glacial cycle, and slow recolonization, high-latitude soils generally lack large earthworms. But this situation is about to change as several species of earthworms are spread to northern habitats through human-mediated dispersal. In this thesis, I investigate the impacts on plant communities and carbon cycling that results from the dispersal of earthworms—primarily Lumbricus and Aporrectodea spp.—in the Fennoscandian Arctic. To achieve this, I combined data from a four-year mesocosm study with observations from earthworm-invaded soils in the Fennoscandian mountain range. My findings indicate that earthworm presence can make tundra ecosystems more graminoid-rich, and cause preferential grazing by rodents, likely due to the higher nitrogen content in plants growing in more fertile soil. My research has revealed that earthworms play a significant role in stimulating tundra plant biomass growth, particularly belowground. I attribute this increase in plant biomass to the extended growing season facilitated by earthworm activity and more plant available nitrogen. This growth enhancement was consistent across different vegetation types but only led to an increase in net ecosystem carbon (C) uptake in dwarf shrub-dominated tundra. In contrast, in meadow tundra, earthworms had no net effect on the ecosystem C pool, due to an increased mineralization of soil organic carbon (SOC), which counterbalanced the enhanced plant carbon sequestration. Furthermore, using species distribution modelling, I confirmed that earthworm dispersal in the Fennoscandian Mountains is likely driven by human vectors. I estimate that approximately 7% of this region currently consists of habitats that are both climatically suitable a, Paper II, correct title: Invasive earthworms alter carbon sequestration in sub-arctic tundra ecosystems

Globally, habitat change is one of the major drivers of biodiversity loss. Similar changes have occurred in Sweden over the past 150 years resulting in loss of habitat complexity at local and landscape scales. In parallel, the climate is changing, with increasing air temperatures in the past 100 years. This changing climate will likely have knock-on effects on habitats and their microclimates. Bats are often considered good indicators of environmental change. However, many bat species are declining globally with north European populations considered the most at risk due to climate change. The effects of habitat and climate change on bats are wide ranging and include loss of foraging habitat, impacts to roost locations, morphological changes and effects on their insect prey. In this thesis I identify how habitat and climate influence bat populations in Sweden, at multiple spatial and temporal scales. Due to the complex nature of these drivers a multi-method approach was used, across a long latitudinal gradient in Sweden. To investigate the drivers of bat morphological change I analysed museum specimens over a 180-year time period together with historical maps, land-use statistics, and temperature data. To understand how habitat complexity at local and landscape scales influences bat activity, I monitored bats acoustically, sampled prey abundance and measured microclimate in a study focusing on forest borders. I also used a citizen science project to investigate bat diet and the local and landscape drivers of roost selection. I found no effect of climate change on bat morphology but jaw size changed over time in two bat species, with increasing jaw size in one species and decreasing in the other. In terms of microclimate, humidity was a strong driver of bat activity. As for effects of landscape level habitat, forest cover influenced wing morphology with bats having shorter, broader wings in more forested landscapes. Furthermore, area of deciduous forest had a posit

Studier av jordens klimatsystem, inklusive de komplexa mekanismerna som driver de globala monsunsystemen, utgör en grundläggande del av forskningen inom klimatvetenskaperna. Monsuner, som är livsviktiga för miljarder människor världen över, representerar komplexa atmosfäriska fenomen som påverkas av ett brett spektrum av globala faktorer. Dessa inkluderar orbitala förändringar som påverkar jordens exponering för solstrålning samt den naturliga variabiliteten i vårt klimatsystem. Specifikt är den Indiska sommarmonsunen (ISM) av särskilt vetenskapligt intresse på grund av dess inverkan på klimatet, jordbruket och tillgängligheten till vatten i Sydasien. Att förstå ISM:s variabilitet genom historien och dess potentiella förändringar i framtiden är avgörande för att kunna förutsäga och anpassa sig till kommande klimatförändringar i denna region. I ett försök att bidra till denna vetenskapliga utmaning har denna avhandling använt sig av en kombination av naturliga arkiv och klimatmodellering. Genom att analysera stabila vattenisotoper från nederbörd och stalagmiter, tillsammans med avancerade simuleringar från klimatmodeller, har vi strävat efter att förstå ISM:s respons på naturliga drivkrafter under nyckelperioder såsom den senaste interglaciala perioden (127 000 år sedan), holocen (11 700 år sedan till nutid) och det senaste årtusendet. Vår forskning visar att ISM är känslig för en rad både lokala och globala faktorer, såsom lokala geografiska egenskaper och avlägsna atmosfäriska förhållanden på ISM:s årliga variabilitet. Monsunens respons på orbitala förändringar, såsom varierande avstånd och vinkel till solen, är särskilt framträdande, vilket understryker den direkta kopplingen mellan rymd- och klimatdynamik. En viktig upptäckt i vår forskning har varit skillnaderna mellan isotopsignaler från klimatmodeller och de i stalagmiter. Dessa skillnader ifrågasätter nuvarande förståelse för hur väl både proxy och modeller återspeglar de naturliga drivkrafternas inverkan på

Natural disasters result in devastating losses in human life, environmental assets, and personal, regional, and national economies. The availability of different big data such as satellite images, Global Positioning System (GPS) traces, mobile Call Detail Records (CDR), social media posts, etc., in conjunction with advances in data analytic techniques (e.g., data mining and big data processing, machine learning and deep learning), can facilitate the extraction of geospatial information that is critical for rapid and effective disaster response. However, disaster response system development usually requires the integration of data from different sources (streaming data sources and data sources at rest) with different characteristics and types, which consequently have different processing needs. Deciding which processing framework to use for a specific big data to perform a given task is usually a challenge for researchers from the disaster management field. While many tasks can be accomplished with population and movement data, for disaster management, a key and arguably most important task is to analyze the displacement of the population during and after a disaster. Therefore, in this thesis, the knowledge and framework resulted from a literature review. These were used to select tools and processing strategies to perform population displacement (the forced movement or relocation of people from their original homes) analysis after a disaster. This is a use case of the framework as well as an illustration of the value and challenges (e.g., gaps in data due to power outages) of using CDR data analysis to support disaster management. Displaced populations were inferred by analyzing the variation of home cell-tower for each anonymized mobile phone subscriber before and after a disaster using CDR data. The effectiveness of the proposed method is evaluated using remote sensing-based building damage assessment data and Displacement Tracking Matrix (DTM) from individuals’ s, Naturkatastrofer leder till förödande förluster i människoliv, miljötillgångar ochpersonlig, regional och nationell ekonomi. Tillgängligheten till olika data, såsomsatellitbilder, GPS-spår (Global Positioning System), detaljerade register av mobilsamtal (CDR), inlägg på sociala medier etc., i kombination med framsteg inomdataanalystekniker (t.ex. datautvinning och stordataberarbetning, maskininlärningoch djupinlärning) kan underlätta utvinningen av geospatial information som är avgörande för snabb och effektiv katastrofinsats. Utvecklingen av katastrofinsatssystem kräver dock vanligtvis integration av data från olika källor (strömmandedatakällor och data i vila) med olika egenskaper och typer, vilka följaktligen harolika bearbetningsbehov. Att bestämma vilket bearbetningsramverk som ska användas för en specifik datatyp för att utföra en given uppgift är vanligtvis en utmaning för forskare från katastrofhanteringsområdet. Medan många uppgifter kanutföras med befolknings- och rörelsedata, är en nyckeluppgift, och utan tvekan denviktigaste uppgiften för katastrofhantering, att analysera befolkningens förflyttningunder och efter en katastrof. I denna avhandling inhämtades därför kunskapen ochramverket genom en litteraturstudie. Dess resultat användes för att välja verktygoch bearbetningsstrategier för att utföra en analys av befolkningsförflyttning efter en katastrof. Detta är ett användningsfall av ramverket samt en illustration avvärdet av och utmaningarna i (t.ex. luckor i data på grund av strömavbrott) attanvända CDR-dataanalys för att stödja katastrofhantering.Mängden av förflyttad befolkning härleddes genom att analysera variationenvid hemmobilmasten för varje anonymiserad mobiltelefonabonnent före och efteren katastrof med hjälp av CDR-data. Metodens effektivitet utvärderas med hjälpav fjärranalysbaserad skadebedömning av byggnader och en Displacement Tracking Matrix (DTM) från individers enkätsvar samlat i skyddsrum efter en allvarlig cyklon i Beira stad, centra

Lakes are important sentinels of climate change and may contribute over 30% of natural methane (CH4) emissions; however, no earth system model (ESM) has represented lake CH4 dynamics. To fill this gap, we refined a process-based lake biogeochemical model to simulate global lake CH4 emissions, including representation of lake bathymetry, oxic methane production (OMP), the effect of water level on ebullition, new non-linear CH4 oxidation kinetics, and the coupling of sediment carbon pools with in-lake primary production and terrigenous carbon loadings. We compiled a lake CH4 data set for model validation. The model shows promising performance in capturing the seasonal and inter-annual variabilities of CH4 emissions at 10 representative lakes for different lake types and the variations in mean annual CH4 emissions among 106 lakes across the globe. The model reproduces the variations of the observed surface CH4 diffusion and ebullition along the gradients of lake latitude, depth, and surface area. The results suggest that OMP could play an important role in surface CH4 diffusion, and its relative importance is higher in less productive and/or deeper lakes. The model performance is improved for capturing CH4 outgassing events in non-floodplain lakes and the seasonal variability of CH4 ebullition in floodplain lakes by representing the effect of water level on ebullition. The model can be integrated into ESMs to constrain global lake CH4 emissions and climate-CH4 feedback.

X-ray based microdensitometry is conventionally used to produce climate-related tree-ring records. Micro X-ray fluorescence (µXRF) applications represent another growing area of interest and opportunities in dendrochronology. This paper demonstrates a method to correctly juxtapose and precisely synchronise the densitometry and µXRF profiles. Among µXRF variables, full fluorescence spectrum (FFS) corresponds distinctly well with the microdensitometry-based wood density variations. Accordingly, the FFS provides the most applicable variable to integrate the µXRF and density profiles. The method proposed here can be used to demonstrate the strength and sign of µXRF variables and wood density relations. Moreover, the µXRF based records can be readily compared to density variables, such as the latewood maximum density, which is demonstrated in this paper.

Many studies are pointing to the fact that cities are experiencing higher temperatures than non-built-up areas. Yet limited can be found on thermal inequalities in the context of vulnerable groups, specifically linked to people living in deprivation. Here, we study heat patterns across vulnerable groups living in deprivation as an important effort that should be paralleled to the other urban climate studies and aim at answering two primary questions: (1) how temperature varies within and across deprived areas, and (2) what the key driving factors are for such variation. We conduct intensive in-situ measurements by involving local residents in air temperature traverse across deprived neighbourhoods and modelling the pattern of air temperature with spatial covariates. We also compare different modelling techniques while securing the interpretability of the air temperature pattern by using understandable spatial covariates, which is especially informative for mitigation and adaptation, and linking scientific exploration and practical solutions.

Marine sediments bury similar to 160 Tg of organic carbon (OC) annually and represent an essential component of the global carbon cycle. OC burial is inherently multifactorial; however, in the past decade, the role of iron in regulating OC burial via the formation of organo-mineral associations, known as "rusty carbon sink," has been extensively studied. Despite widespread recognition, the origin of the OC preserved within these associations and the effect of the bottom-water oxygenation on their stability are still debated. Here, we investigate the rusty carbon sink in sediments collected across transects from the head to mouth of three Swedish fjords presenting contrasting bottom-water oxygenation regimes (the oxic Hake fjord, seasonally hypoxic Gullmar fjord, and anoxic By fjord). We found that the oxygenation regimes, the intensity of benthic iron cycling or the OC origin have little to no influence on the amount of OC bound to Fe (OC - Fe). The lack of correlation with any of the parameters studied, in combination with an increase in the OC - Fe in the fjords with riverine input suggest, at least partially, an allochthonous origin of these organo-mineral associations. Our results also show that the rusty carbon sink plays a modest role in the OC burial in these fjords (similar to 6% OC is bound to Fe). While these fjords still represent important OC burial hotspots with an average of similar to 35 g C m-2 buried annually, the OC burial is controlled by other sedimentary processes, such as the high mass accumulation rates found in these fjord systems., Funding Agencies|Fonds National de la Recherche Scientifique [FRS-FNRS PDR-T002019F]; Belgian Science Policy Office [RV/21/CANOE]; Research Foundation-Flanders (FWO) [1241724N]; Swedish Agency for Marine and Water Management (HaV) [2535-20]

Problematiken kring åtgärden anvisad plats bygger tills tor del på konflikten mellan fastighetsägarnas olägenhet i form av, utifrån deras synsätt, sämre placering av avfallskärl som förväntas bära med sig obehaglig lukt, ohyra och sämre tillgänglighet gentemot renhållningsarbetarnas bristande arbetsmiljö. En konflikt som renhållningsarbetarna eller rättare sagt kommunen ses komma vinnandes ur. Den rekommenderade lösningen på problematiken enligt studien anses vara att öka förståelsen till rättsfallens utfall samt förtydliga den praxis som dessa utfall bygger på. En ökad förståelse skulle möjligtvis kunna förbättra samtliga parternas inställning inför åtgärden och förhoppningsvis minska antalet fall som går ända upp till mark- och miljööverdomstolen. Detta utfall hade varit en vinst för samtliga inblandade. Slutsatsen av studiens genomförande är att åtgärden anvisad plats blir ett slags utlopp för vad som annars hade kunna utvecklats till ett skyttegravskrig där parterna inte finner någon lösning på det påtagliga arbetsmiljöproblem som renhållningspersonalen då behöver utstå. Vidare att den praxis som vuxit fram pekar på vikten at kommunens avfallsplan och avfallsföreskrifter, att kommunen måste vara en aktiv part i anvisandet av plats för hämtning av avfall, att avstånd på 400-500 meter till anvisad plats är inte oskälig samt att kommunen kan endast anvisa plats för hämtning av avfall på ytor som de har rådighet över. Problemet kring missnöjet hos fastighetsägarna kanske inte ser så stort ut i det enskilda fallet sett långsiktigt kan detta ha negativ inverkan rättsapparaten. Om fler och fler fastighetsägare upplever att de fått ett negativt utfall i prövningen av sitt beslut kan det tänkas skada myndigheternas och rättsapparatens förtroende. Studien har inget svar på denna svårighet utan kan endast belysa dess existerande, The problems surrounding the assigned place measure are largely based on the conflict between the property owners' inconvenience in the form of, from their point of view, poor placement of waste receptacles that are expected to carry unpleasant odors, vermin and poorer accessibility compared to the poor working environment of the cleaning workers. A conflict that the cleaning workers, or rather the township, is seen to emerge victorious from. The recommended solution to the problem according to the study is considered to be to increase understanding of the outcome of legal cases and to clarify the practice on which these outcomes are based. An increased understanding could possibly improve the attitude of all parties towards the measure and hopefully reduce the number of cases that go all the way to the Land and Environmental Court of Appeal. This outcome would be a win for everyone involved. The conclusion of the study's implementation is that the assigned place measure becomes a kind of outlet for what could otherwise have developed into a trench war where the parties cannot find a solution to the tangible work environment problem that the cleaning staff then have to endure. Furthermore, that the practice that has emerged points to the importance of the township’s waste plan and waste regulations, that the township must be an active party in assigning a place for collecting waste, that a distance of 400-500 meters to the assigned place is not unreasonable and that the township can only assign a place for collecting waste on properties that they have at their disposal. The problem surrounding the dissatisfaction of the property owners may make that big of an impact in the individual case but, in the long term, this can have a negative impact on the whole legal system. If more and more property owners feels like they have received a negative outcome in the examination of their decision, it can conceivably damage the trust of the authorities and the judicial system.

För att uppnå klimatmålen inom transportsektorn, krävs ett minskat bilåkande och en omställning av fordonsflottan. Ett medel för förändring och påverkan av transporter är parkeringen, för att styra transportval och resmönster. Kommunens parkeringsnormer påverkar mängden parkeringsplatser vidny- och ombyggnationer. För att bedöma en parkeringsplats miljöpåverkan på den globala uppvärmningspotentialen (GWP) under dess livstid har en ny systemavgränsning fastställts för vilka utsläpp som ska tillskrivas en parkeringsplats. Det görs genom en livscykelanalys (LCA) av ett garage i en källare. För att bedöma miljöpåverkan från garagets livscykel inkluderas även användning av parkeringsplatsen. Vilketinkluderar bilarnas miljöpåverkan under dess livscykel under garagets livstid. Utsläppen för byggandet av garaget uppgår till 1697 ton koldioxidekvivalenter (CO2e) och för det tillhörande markarbetet till 106 ton CO2e, där markarbetet svarar för 6 procent av den totala utsläppen från byggandet. När utsläppen från byggnaden och markarbetet kombineras för att beräkna den totala miljöpåverkan per parkeringsplats, uppgår markarbetet till cirka 0,8 ton CO2e och byggandet av garaget till 13 ton CO2e. För beräkningen av parkeringsanvändningen har en konsekvens-LCA använts för att se till dess miljöpåverkan för användningsstadium. Baseras på två scenarier för framtida utveckling av utsläppen för en Volvo XC40 ICE och en Volvo XC40 Recharge under parkeringsplatsens livslängd på 50 år. Ett av scenarierna är ett basscenario där utvecklingen stagnerar och utsläppen ligger kvar på samma nivåer. Det andra är ett samhällsomställningsscenario där klimatmålen uppnås och samhället ställer om, vilket minskar utsläppen till att nå klimatneutralitet. Båda scenarierna innefattar Europeiska unionens förbud mot försäljning av den fossildrivna bilen (Volvo XC40 ICE) år 2035. Resultaten visar att utsläppen per parkeringsplats varierar beroende på biltyp och antal bilar i garagets startuppsättning, med, To achieve the climate goals for the transport sector, reduced car usage and a transition of the vehicle fleet are required. As a means of change and impact on transportation, parking is used as a tool to influence transport choices and travel patterns. Parking norms affect the construction and reconstruction of parking spaces. To assess the environmental impact of a parking space in terms of its Global Warming Potential (GWP) over its lifetime, a new system boundary has been established for the emissions attributable to a parking space. This is done through a Life Cycle Assessment (LCA) of an underground garage. To assess the environmental impact of the garage's life cycle, the use of the parking space is also included, which encompasses the environmental impact of the cars over their life cycle during the garage's lifetime. The emissions from the construction of the garage amount to 1697 tons of carbon dioxide equivalents (CO2e) and for the associated groundwork to 106 tons CO2e, where the groundwork accounts for 6 percent of the total emissions from the construction. When the emissions from the building and the groundwork are combined to calculate the total environmental impact per parking space, the groundwork amounts to approximately 0.8 tons CO2e and the construction of the garage to 13 tons CO2e. For the calculation of parking usage, a consequential LCA has been used to assess its environmental impact during the usage phase. This is based on two scenarios for the future development of emissions for a Volvo XC40 ICE and a Volvo XC40 Recharge during the parking space's lifespan of 50 years. One of the scenarios is a baseline scenario where development stagnates, and emissions remain at the same levels. The other is a societal transformation scenario where climate goals are achieved and society transitions, reducing emissions to achieve climate neutrality. Both scenarios include the European Union's ban on the sale of fossil-fueled cars (Volvo XC40 ICE) in 2035.

Monitoring the spatial distribution and trends in surface greenhouse gas (GHG) fluxes, as well as flux attribution to natural and anthropogenic processes, is essential to track progress under the Paris Agreement and to inform its global stocktake. This study updates earlier syntheses (Petrescu et al., 2020, 2021, 2023), provides a consolidated synthesis of CH4 emissions using bottom-up (BU) and top-down (TD) approaches for the European Union (EU), and is expanded to include seven additional countries with large anthropogenic and/or natural emissions (the USA, Brazil, China, India, Indonesia, Russia, and the Democratic Republic of the Congo (DR Congo)). Our aim is to demonstrate the use of different emission estimates to help improve national GHG emission inventories for a diverse geographical range of stakeholders.We use updated national GHG inventories (NGHGIs) reported by Annex I parties under the United Nations Framework Convention on Climate Change (UNFCCC) in 2023 and the latest available biennial update reports (BURs) reported by non-Annex I parties. Comparing NGHGIs with other approaches highlights that different system boundaries are a key source of divergence. A key system boundary difference is whether anthropogenic and natural fluxes are included and, if they are, how fluxes belonging to these two sources are partitioned.Over the studied period, the total CH4 emission estimates in the EU, the USA, and Russia show a steady decreasing trend since 1990, while for the non-Annex I emitters analyzed in this study, Brazil, China, India, Indonesia, and DR Congo, CH4 emissions have generally increased. Quantitatively, in the EU the mean of 2015-2020 anthropogenic UNFCCC NGHGIs (15 +/- 1.8 Tg CH4 yr-1) and the mean of the BU CH4 emissions (17.8 (16-19) Tg CH4 yr-1) generally agree on the magnitude, while inversions show higher emission estimates (medians of 21 (19-22) Tg CH4 yr-1 and 24 (22-25) Tg CH4 yr-1 for the three regional and six global inversions, respectiv, Funding Agencies|EU

Arctic permafrost-affected soils store large amounts of carbon, and high-quality maps of these soils are needed to model climate feedbacks from permafrost thaw. Ice-rich polygonal tundra is one landscape type that is widespread in the Arctic and rich in carbon. These environments are especially susceptible to climate change as thawing of ground ice causes the irreversible degradation of these landforms. The thawing processes open pathways for release of carbon that has been preserved under frozen conditions over long timescales. This release can occur through gradual thickening of the active layer, which is the upper ground layer that thaws seasonally, but also through abrupt thaw processes, such as thermokarst formation following thaw of ice-rich ground. To better project the future trajectory of permafrost carbon at local to regional scales we need high-resolution information on soil and landscape properties. This thesis aims to combine field sampling and spatial modeling to investigate the soils and landforms of permafrost landscapes along the Canadian Yukon coast of the Beaufort Sea coast. A major focus of this thesis is on mapping the variability of the landscape on different scales, as most pan-Arctic studies have a coarse resolution and do not capture local variability. It utilizes advanced machine learning methods for digital soil mapping to analyze soil organic carbon and nitrogen stock distributions across multiple scales, while also assessing the associated uncertainties. The availability of high- and medium-resolution (here defined as <10 m and ≥10 m pixels resolution) satellite imagery enables detailed landcover mapping, and this thesis explores various pattern recognition methods for landcover classification. The results show that parallel analyses at multiple scales is necessary to understand carbon storage and landscape dynamics. For studies beyond the local scale medium-resolution data has the advantage of capturing differences at the landform le

Headwater streams are important conduits for terrestrial carbon (C) and nutrients and are shaped and characterised by the landscape they drain. They evade significant amounts of carbon dioxide (CO2) to the atmosphere relative to their surface area and receive C and nutrients from land, which affect stream functions such as metabolism from biofilms and CO2 evasion. In boreal and Arctic zones, these processes are regarded to be largely controlled by factors such as temperature, discharge, and forestry. These factors vary in space and time, yet how they alter stream C and nutrient cycling is still poorly constrained. This thesis therefore asks how catchment variability affects nutrient limitation patterns and C fluxes, as well as how these effects are related to groundwater input and altered by forestry in Swedish boreal and Arctic headwater streams. I found that the nutrient limitation status of stream biofilms can vary from nitrogen to phosphorous limitation within an Arctic catchment. In a boreal headwater stream, I show that CO2 evasion rates varied up to 12-fold along a relatively short distance. Using radon as tracer for groundwater in the same reach, I also show that the majority of CO2 evaded to the atmosphere was supplied by groundwater input. Across the open water season, I show that 17% of stream C was lost through CO2 evasion to the atmosphere compared to 83% transported downstream. When combining vertical and horizontal C fluxes, I found that the reach scale C evasion:export ratio varies from 0.03 to 0.37 and was mainly controlled by discharge. Further, clear-cutting parts of the forest around a boreal stream increased stream water CO2 concentrations as well as CO2 evasion in the first two years after clear-cutting. Moreover, I found that the diel difference between nighttime and daytime CO2 evasion increased in the second year after clear-cutting in concert with increased nitrogen and phosphorous concentrations which suggest elevated CO2 cycling by metab

The greenery of floodplain meadows in arid regions, such as Mongolia, is influenced by climate, hydrology, and land use. In this study, we analyzed the NDVI (Normalized Difference Vegetation Index) of two floodplain meadows located along the South Tamir and Tamir Rivers using LANDSAT images. Our goal was to observe NDVI spatial changes, variations, and mean values in mid-August every six years from 1991 to 2015 and to identify the factors driving these differences. To achieve this, we conducted variance analysis to identify changes in NDVI and implemented Principal Component Analysis to determine the influence of hydro-meteorological factors and grazing intensity. Our findings indicate a significant decrease in greenness, as measured by pixel-scale NDVI, during the late summer period. This decrease was consistently observed, except for a series of harsh winters that followed relatively dry summers, resulting in a disastrous event called dzud, which led to the death of livestock. The decrease in NDVI was amplified by lower precipitation in June, higher temperatures and wind speed in July, and increased precipitation in August, along with a higher frequency of days with convective rain. Our findings have important implications for managing grazing in Mongolia’s grasslands, promoting sustainable land use, and mitigating sandstorms. The variance and average values of NDVI at the pixel level can serve as reliable markers of sustainable pasture management in areas where other vegetation measures are limited.

Substantial uncertainties exist regarding how future climate change will affect storminess (storm frequency and intensity) in Ireland and the United Kingdom (UK). Knowledge about spatiotemporal variations of past storminess gives us a better understanding of its mechanisms on centennial to millennial time scales, as well as the impact of external forcing on future storminess in climate models. Here, we present the oldest storm record to date from Ireland, covering the last 8000 years, reconstructed from the Roycarter Bog, a coastal blanket bog in north-western Ireland. The sequence was analysed for grain-size, chemical, mineral and organic molecular composition. The chronology was built on 11 AMS radiocarbon dates. The deposit characteristics, location and low inorganic content suggest aeolian transport of particles to the bog throughout the studied period. Cluster analysis of the grain-size frequency curves, along with the coarse to fine sand ratio, allowed the identification of eleven storm periods (cal yr BP): 6150–5500 (1); 4970–4130 (2); 4000 (3); 3490–3290 (4); 3230 (5); 2850–2590 (6); 2170–1920 (7); 1440 (8); 1225–890 (9); 620–470 (10); and 290–230 (11). During the mid-Holocene, the relative sea level was lower and the local beach sources located further away, giving a longer transport distance compared to the late Holocene. In the latter part of the mid-Holocene (6150–4130 cal yr BP), during the Holocene thermal maximum, increased storminess and wind strengths were inferred for north-western Ireland, manifested as two longer storm periods. During the late Holocene the storm frequency increased, and a greater number (9) of shorter storm periods were recorded. Comparison between our results and regional peat palaeostorm records from Scotland, north of our study site, showed an antiphase relationship between storminess in Ireland and Scotland during the latter part of the mid-Holocene, but mostly in-phase storminess over the last 3000 years. Taken together, enh

The importance of floodplains in carbon (C) evasion from the lotic systems is especially important in continental plains of low runoff such as the organic-rich Western Siberian Lowland (WSL). To quantify the relative importance of the floodplain compared to main stem CO2 emissions, we monitored a large region of the Ob River's middle course (permafrost-free zone) over 3 months from spring to summer. We calculated seasonal water coverage using remote sensing, GIS and hydrologically-based approaches and measured CO2 emissions using floating chambers. There was a strongly pronounced seasonality in the water area's extent of the floodplain with water covering > 40 % of land during the ∼ 30 days of the most intensive spring flood (May – June) and subsequently declining to ≤ 10 % during summer (July-August). Maximal CO2 emissions were recorded in most shallow water bodies of the floodplain, notably in temporary flooded fens and birch forests. The CO2 emissions during the study period ranged from 0.2 ± 0.2 to 0.9 ± 0.2 g Cm−2 d−1 for the floodplain and 0.03 ± 0.34 g C m−2 d−1 for the Ob's main channel. CO2 emissions from the floodplain were ∼ 163 ± 20 t C per km for the river's main stem during the 95 day study period. The partial contributions of temporary flooded zones, main stem, and permanent lakes / secondary channels to total emissions (1820 km² area) were 70, 16, and 14 %, respectively. Over spring and summer seasons, contributions from flooded zones ranged from 43 to 99 % of total CO2 emissions from water surfaces of the Ob River's middle course. Extrapolation of obtained results to the entire territory of the Ob River floodplain indicates that not accounting for the floodplain emissions may sizably—up to an order of magnitude—underestimate the CO2 emissions from riverine systems in Western Siberia during open water period. Future work on the Ob River floodplain in the permafrost-bearing zone should be prioritized and would allow adequate upscaling of C emission

The Arctic region is warming at over twice the mean rate of the Northern Hemisphere and nearly four times faster than the globe since 1979. The local rate of warming is even higher in the European archipelago of Svalbard. This warming is transforming the terrestrial snow cover, which modulates surface energy exchanges with the atmosphere, accounts for most of the runoff in Arctic catchments and is also a transient reservoir of atmospherically deposited compounds, including pollutants. Improved observations, understanding and modelling of changes in Arctic snow cover are needed to anticipate the effects these changes will have on the Arctic climate, atmosphere, terrestrial ecosystems and socioeconomic factors. Svalbard has been an international hub of polar research for many decades and benefits from a well-developed science infrastructure. Here, we present an agenda for the future of snow research in Svalbard, jointly developed by a multidisciplinary community of experts. We review recent trends in snow research, identify key knowledge gaps, prioritize future research efforts and recommend supportive actions to advance our knowledge of present and future snow conditions pertaining to glacier mass balance, permafrost, surface hydrology, terrestrial ecology, the cycling and fate of atmospheric contaminants, and remote sensing of snow cover. This perspective piece addresses issues relevant to the circumpolar North and could be used as a template for other national or international Arctic research plans.

Rangelands face threats from climate and land-use change, including inappropriate climate change mitigation initiatives such as tree planting in grassy ecosystems. The marginalization and impoverishment of rangeland communities and their indigenous knowledge systems, and the loss of biodiversity and ecosystem services, are additional major challenges. To address these issues, we propose the wilder rangelands integrated framework, co-developed by South African and European scientists from diverse disciplines, as an opportunity to address the climate, livelihood, and biodiversity challenges in the world’s rangelands. More specifically, we present a Theory of Change to guide the design, monitoring, and evaluation of wilder rangelands. Through this, we aim to promote rangeland restoration, where local communities collaborate with regional and international actors to co-create new rangeland use models that simultaneously mitigate the impacts of climate change, restore biodiversity, and improve both ecosystem functioning and livelihoods.

Peatlands are major terrestrial soil carbon stores, and open mires in boreal landscapes hold a considerable fraction of the global peat carbon. Despite decades of study, large-scale spatiotemporal analyses of mire arrangement have been scarce, which has limited our ability to scale-up mire properties, such as carbon accumulation to the landscape level. Here, we use a land-uplift mire chronosequence in northern Sweden spanning 9,000 years to quantify controls on mire distribution patterns. Our objectives include assessing changes in the spatial arrangement of mires with land surface age, and understanding modifications by upland hydrotopography. Characterizing over 3,000 mires along a 30 km transect, we found that the time since land emergence from the sea was the dominant control over mire coverage, especially for the establishment of large mire complexes. Mires at the youngest end of the chronosequence were small with heterogenous morphometry (shape, slope, and catchment-to-mire areal ratios), while mires on the oldest surfaces were variable in size, but included larger mires with more complex shapes and smaller catchment-to-mire ratios. In general, complex topography fragmented mires by constraining the lateral expansion, resulting in a greater number of mires, but reduced total mire area regardless of landscape age. Mires in this study area occurred on slopes up to 4%, indicating a hydrological boundary to peatland expansion under local climatic conditions. The consistency in mire responses to spatiotemporal controls illustrates how temporal limitation in peat initiation and accumulation, and topographic constraints to mire expansion together have shaped present day mire distribution patterns.

In the rapidly warming circumpolar Arctic, recent research of lakes has focused on their climatology and ecology but is challenged by sparsity of wintertime data. At the c. 48-m-deep and c. 0.5-km2 large proglacial Darfaljavri (Lake Tarfala), located in an arctic-alpine environment in the Scandinavian Mountains, year-round water temperatures were previously reported for 2016 to 2019. Here, this record is continued for 2019-2020 and 2021-2022, complemented by time-lapse imagery records of the state of the lake surface, as well as degree-day modeling of ice phenology (timing of ice-on and ice-off). Darfaljavri is cryostratified during winter, with interannual variations in the thermocline's thickness and temperature range. The ice season lasts from October to July. Modeled ice-on dates match observed ones reasonably well; however, observed ice-off dates occur much later than modeled ones, likely because of cold impact from Darfaljavri's glacial environment as inferred from a comparison with a close tundra lake. Though new insights into the complex lake mixing and ice phenology are provided, it remains to attribute the characteristics of Darfaljavri's winter stratification to additional potential drivers, such as lake ice thickness, atmospheric heat fluxes, and the water balance of the lake.

Current estimates of carbon dioxide (CO2) evasion from Arctic lakes are highly uncertain because few studies integrate seasonal variability, specifically evasion during spring ice-melt. We quantified annual CO2 evasion for 14 clear-water Arctic lakes in Northern Sweden through mass balance (ice-melt period) and high-frequency loggers (open-water period). On average, 80% (SD: ± 18) of annual CO2 evasion occurred within 10 d following ice-melt. The contribution of the ice-melt period to annual CO2 evasion was high compared to earlier studies of Arctic lakes (47% ± 32%). Across all lakes, the proportion of ice-melt : annual CO2 evasion was negatively related to the dissolved organic carbon concentration and positively related to the mean depth of the lakes. The results emphasize the need for measurements of CO2 exchange at ice-melt to accurately quantify CO2 evasion from Arctic lakes., Originally included in thesis in manuscript form.

This paper presents a hydrological assessment of the 113,981 km2 Meta River basin in Colombia using 13 global climate models to predict water yield for 2050 under two CMIP6 scenarios, SSP 4.5 and SSP 8.5. Despite mixed performance across subbasins, the model was notably effective in the upper Meta River subbasin. This study predicts an overall increase in the basin's annual water yield due to increased precipitation, especially in flatter regions. Under the SSP 4.5, the Meta River basin's water flow is expected to rise from 5141.6 m3/s to 6397.5 m3/s, and to 6101.5 m3/s under the SSP 8.5 scenario, marking 24% and 19% increases in water yield, respectively. Conversely, the upper Meta River subbasin may experience a slight decrease in water yield, while the upper Casanare River subbasin is predicted to see significant increases. The South Cravo River subbasin, however, is expected to face a considerable decline in water yield, indicating potential water scarcity. This study represents a pioneering large-scale application of the InVEST-AWY model in Colombia using CMIP6 global climate models with an integrated approach to produce predictions of future water yields.

Climatic and anthropogenic disturbances play pivotal roles in shaping the dynamics of grassland. Quantifying their impacts on grassland variation is essential to ensure sustainable grassland management. In this study, we employed the Thornthwaite Memorial and Carnegie-Ames-Stanford-approach (CASA) models to investigate the spatiotemporal effects of these two variables on grassland variation in northern China from 2000 to 2016, using the net primary productivity (NPP) as a measure. Our findings reveal that approximately 25.92% of the grassland in northern China experienced degradation, while restored grasslands occupied 45% of the total grassland area. The average grassland actual NPP (ANPP) and human-induced NPP decreased at rates of -0.60 and -5.62 gC m-2 a-1, respectively. Conversely, potential NPP exhibited an upward trend with an average increase of 2.27 gC m-2 a-1. Furthermore, grassland ANPP showed a projected increase in most parts of northern China. Climate change emerged as the primary driver for grassland restoration in Xinjiang, Qinghai, and Inner Mongolia, leading to an increase of 21582.79 Gg C in grassland NPP. In contrast, human activities were the dominant catalysts for grassland degradation, resulting in a reduction of 51932.3 Gg C in grassland NPP. Human-induced grassland degradation was ubiquitous in northwest and northeast China. With the exception of slope grassland, climate change primarily influenced the restoration of most grassland types, while human activities were the primary cause of degradation. Our analysis indicated a strong correlation between temperature and grassland degradation, while precipitation played a pivotal role in grassland restoration in northern China. Human interference demonstrated both positive and negative impacts on grassland changes. In conclusion, the increase in precipitation and the implementation of ecological restoration plans have effectively promoted the restoration of grasslands in northern China.

Climate warming at the end of the last glacial period had profound effects on the distribution of cold-adapted species. As their range shifted towards northern latitudes, they were able to colonise previously glaciated areas, including remote Arctic islands. However, there is still uncertainty about the routes and timing of colonisation. At the end of the last ice age, reindeer/caribou (Rangifer tarandus) expanded to the Holarctic region and colonised the archipelagos of Svalbard and Franz Josef Land. Earlier studies have proposed two possible colonisation routes, either from the Eurasian mainland or from Canada via Greenland. Here, we used 174 ancient, historical and modern mitogenomes to reconstruct the phylogeny of reindeer across its whole range and to infer the colonisation route of the Arctic islands. Our data shows a close affinity among Svalbard, Franz Josef Land and Novaya Zemlya reindeer. We also found tentative evidence for positive selection in the mitochondrial gene ND4, which is possibly associated with increased heat production. Our results thus support a colonisation of the Eurasian Arctic archipelagos from the Eurasian mainland and provide some insights into the evolutionary history and adaptation of the species to its High Arctic habitat.

Aim: The microclimate and light conditions on the forest floor are strongly modified by tree canopies. Therefore, we need to better consider the micro-environment when quantifying trait–environment relationships for forest understorey plants. Here, we quantify relationships between micro-environmental conditions and plant functional traits at the community level, including intraspecific trait variation, and their relationship with microclimate air temperature, light and soil properties. Location: Deciduous temperate forests across Europe. Time period: 2018. Major taxa studied: Herbaceous vegetation. Methods: We sampled 225 plots across 15 regions along four complementary gradients capturing both macro- and microclimatic conditions including latitude, elevation, forest management and distance to forest edges. We related the community-weighted mean of five plant functional traits (plant height, specific leaf area [SLA], plant carbon [C], plant nitrogen [N] and plant C:N ratio) across 150 vascular plant species to variation in local microclimate air temperature, light and soil properties. We tested the effect of accounting for intraspecific variation in trait–environment relationships and performed variation partitioning to identify major drivers of trait variation. Results: Microclimate temperature, light availability and soil properties were all important predictors of community-weighted mean functional traits. When light availability and variation in temperature were higher, the herb community often consisted of taller plants with a higher C:N ratio. In more productive environments (e.g. with high soil nitrogen availability), the community was dominated by individuals with resource-acquisitive traits: high SLA and N but low C:N. Including intraspecific trait variation increased the strength of the trait–micro-environment relationship, and increased the importance of light availability. Main conclusions: The trait–environment relationships were much stronger when the

A large fraction of plant litter comprises recalcitrant aromatic compounds (lignin and other phenolics). Quantifying the fate of aromatic compounds is difficult, because oxidative degradation of aromatic carbon (C) is a costly but necessary endeavor for microorganisms, and we do not know when gains from the decomposition of aromatic C outweigh energetic costs. To evaluate these tradeoffs, we developed a litter decomposition model in which the aromatic C decomposition rate is optimized dynamically to maximize microbial growth for the given costs of maintaining ligninolytic activity. We tested model performance against > 200 litter decomposition datasets collected from published literature and assessed the effects of climate and litter chemistry on litter decomposition. The model predicted a time-varying ligninolytic oxidation rate, which was used to calculate the lag time before the decomposition of aromatic C is initiated. Warmer conditions increased decomposition rates, shortened the lag time of aromatic C oxidation, and improved microbial C-use efficiency by decreasing the costs of oxidation. Moreover, a higher initial content of aromatic C promoted an earlier start of aromatic C decomposition under any climate. With this contribution, we highlight the application of eco-evolutionary approaches based on optimized microbial life strategies as an alternative parametrization scheme for litter decomposition models.

The pressing issue of global warming is particularly evident in urban areas, where urban thermal islands amplify the warming effect. Understanding land surface temperature (LST) changes is crucial in mitigating and adapting to the effect of urban heat islands, and ultimately addressing the broader challenge of global warming. This study estimates LST in the city of Yazd, Iran, where field and high-resolution thermal image data are scarce. LST is assessed through surface parameters (indices) available from Landsat-8 satellite images for two contrasting seasons—winter and summer of 2019 and 2020, and then it is estimated for 2021. The LST is modeled using six machine learning algorithms implemented in R software (version 4.0.2). The accuracy of the models is measured using root mean square error (RMSE), mean absolute error (MAE), root mean square logarithmic error (RMSLE), and mean and standard deviation of the different performance indicators. The results show that the gradient boosting model (GBM) machine learning algorithm is the most accurate in estimating LST. The albedo and NDVI are the surface features with the greatest impact on LST for both the summer (with 80.3% and 11.27% of importance) and winter (with 72.74% and 17.21% of importance). The estimated LST for 2021 showed acceptable accuracy for both seasons. The GBM models for each of the seasons are useful for modeling and estimating the LST based on surface parameters using machine learning, and to support decision-making related to spatial variations in urban surface temperatures. The method developed can help to better understand the urban heat island effect and ultimately support mitigation strategies to improve human well-being and enhance resilience to climate change.

Grain size assessments are necessary for understanding the various geomorphological, hydrological and ecological processes that occur within rivers. Recent research has shown that the application of Structure-from-Motion (SfM) photogrammetry to imagery from uncrewed aerial vehicles (UAVs) shows promise for rapidly characterising grain sizes along rivers in comparison to traditional field-based methods. Here, we evaluated the applicability of different methods for estimating grain sizes in gravel bars along a study reach in the Olentangy River in Columbus, Ohio. We collected imagery of these gravel bars with a UAV and processed those images with SfM photogrammetry software to produce three-dimensional point clouds and orthomosaics. Our evaluation compared statistical models calibrated on topographic roughness, which was computed from the point clouds, and to those based on image texture, which was computed from the orthomosaics. Our results showed that statistical models calibrated on image texture were more accurate than those based on topographic roughness. This might be because of site-specific patterns of grain size, shape and imbrication. Such patterns would have complicated the detection of topographic signatures associated with individual grains. Our work illustrates that UAV-SfM approaches show potential to be used as an accessible method for characterising surface grain sizes along rivers at higher spatial and temporal resolutions than those provided by traditional methods.

Urban green–blue infrastructure (GBI) can provide important benefits to urban residents but may also affect mosquito abundance, with associated negative nuisance and infection transmission impacts. This study addresses important knowledge and quantification gaps for the relationships between mosquito prevalence and GBI features within cities. This is done for the city of Uppsala in Sweden as an urban case example, where mosquitos were captured and ambient air temperature and humidity were observed at seven different locations in the summer of 2022. A weighted multi-critera analysis (WMCA) model was developed based on relevant open data and open tools for resolving the mosquito (Culex pipiens) variations based on geographical variables, such as land cover/use, leaf area index, and building and green (vegetation) area fractions, within the city. The results show a clear relationship between mosquito prevalence and green-area fraction (of grass and trees), indicating that urban GBI extension can enhance mosquito prevalence, with possible associated negative impacts. This relationship is supported directly by data, showing significantly higher mosquito prevalence with higher ambient humidity, which in turn is related to larger green-area fraction. The developed WMCA model emerges as a promising tool, e.g., for urban development planning that needs to account for and seek relevant trade-off balances between positive and negative effects of urban GBI changes.

Evapotranspiration (E), a pivotal phenomenon inherent to hydrological and thermal dynamics, assumes a position of utmost importance within the intricate framework of the water–energy nexus. However, the quantitative study of E on a large scale for the “Grain for Green” projects under the backdrop of climate change is still lacking. Consequently, this study examined the interannual variations and spatial distribution patterns of E, transpiration (Et), and soil evaporation (Eb) in the Northern Foot of Yinshan Mountain (NFYM) between 2000 and 2020 and quantified the contributions of climate change and vegetation greening to the changes in E, Et, and Eb. Results showed that E (2.47 mm/a, p < 0.01), Et (1.30 mm/a, p < 0.01), and Eb (1.06 mm/a, p < 0.01) all exhibited a significant increasing trend during 2000–2020. Notably, vegetation greening emerged as the predominant impetus underpinning the augmentation of both E and Eb, augmenting their rates by 0.49 mm/a and 0.57 mm/a, respectively. In terms of Et, meteorological factors emerged as the primary catalysts, with temperature (Temp) assuming a predominant role by augmenting Et at a rate of 0.35 mm/a. Temp, Precipitation (Pre), and leaf area index (LAI) collectively dominated the proportional distribution of E, accounting for shares of 32.75%, 28.43%, and 25.01%, respectively. Within the spectrum of predominant drivers influencing Et, Temp exerted the most substantial influence, commanding the largest proportion at 33.83%. For Eb, the preeminent determinants were recognized as LAI and Temp, collectively constituting a substantial portion of the study area, accounting for 32.10% and 29.50%, respectively. The LAI exerted a pronounced direct influence on the Et, with no significant effects on E and bare Eb. Wind speed (WS) had a substantial direct impact on both E and Et. Pre exhibited a strong direct influence on E, Et, and Eb. Relative humidity (RH) significantly affected E directly. Temp primarily influenced Eb

Soil is a hidden ecosystem which harbours plant roots and countless microorganisms, vital for sustaining life aboveground. These belowground communities provide essential ecosystem services like soil stabilisation and organic matter decomposition. Soil is also one of the largest terrestrial carbon repositories, and land management strategies aimed at increasing organic matter inputs from plants, such as compost additions, can promote further soil carbon accumulation. Because organic carbon is important for soil water retention, this management may also help to increase resilience against more frequent and intense droughts. Although roots and microbial communities are largely acknowledged to play a key role in regulating the carbon cycle, there are still many open questions regarding the link between above- and belowground processes and ecosystem functions. Observing climate- and management-driven changes in the soil habitat is fundamental for understanding how ecosystems respond to environmental change. The aim of this thesis is to explore the relationship between soil properties, plant communities, and soil microbial communities in response to environmental changes. The research builds on a meta-analysis of drought effects on grasslands, and a multifactorial field experiment which combined three years of precipitation reduction and a compost treatment in two Swedish grasslands. We analysed the response of roots and soil microbial communities to drought and compost amendments, and identified environmental factors behind their large spatial variability. Finally, we tested the effects of compost additions on soil carbon storage and its interactions with drought. The results of the meta-analysis indicate that, on a global scale, grassland roots and shoots have diverging responses to drought duration and intensity, with long-term climate mediating that difference. At the local scale assessed in the field experiment, we observed that the spatial patterns of soil microbia

Deep learning and remote sensing techniques have significantly advanced water surface monitoring; however, the need for annotated data remains a challenge. This is particularly problematic in wetland detection, where water extent varies over time and space, demanding multiple annotations for the same area. In this paper, we present DeepAqua, a deep learning model inspired by knowledge distillation (a.k.a. teacher–student model) to generate labeled data automatically and eliminate the need for manual annotations during the training phase. We utilize the Normalized Difference Water Index (NDWI) as a teacher model to train a Convolutional Neural Network (CNN) for segmenting water from Synthetic Aperture Radar (SAR) images. To train the student model, we exploit cases where optical- and radar-based water masks coincide, enabling the detection of both open and vegetated water surfaces. DeepAqua represents a significant advancement in computer vision techniques for water detection by effectively training semantic segmentation models without any manually annotated data. Experimental results show that DeepAqua outperforms other unsupervised methods by improving accuracy by 3%, Intersection Over Union by 11%, and F1-score by 6%. This approach offers a practical solution for monitoring wetland water extent changes without the need of ground truth data, making it highly adaptable and scalable for wetland monitoring.

Despite the scientific progress in drought detection and forecasting, it remains challenging to accurately predict the corresponding impact of a drought event. This is due to the complex relationships between (multiple) drought indicators and adverse impacts across different places/hydroclimatic conditions, sectors, and spatiotemporal scales. In this study, we explored these relationships by analyzing the impacts of the severe 2018–2019 central European drought event in Germany. We first computed the standardized precipitation index (SPI), the standardized precipitation evaporation index (SPEI), the standardized soil moisture index (SSMI) and the standardized streamflow index (SSFI) over various accumulation periods, and then related these indicators to sectorial losses from the European drought impact report inventory (EDII) and media sources. To cope with the uncertainty associated with both drought indicators and impact data, we developed a fuzzy method to categorize them. Lastly, we applied the method at the region level (EU NUTS1) by correlating monthly time series. Our findings revealed strong and significant relationships between drought indicators and impacts over different accumulation periods, albeit in some cases region-specific and time-variant. Furthermore, our analysis established the interconnectedness between various sectors, which displayed systematically co-occurring impacts. As such, our work provides a new framework to explore drought indicators-impacts dependencies across space, time, sectors, and scales. In addition, it emphasizes the need to leverage available impact data to better forecast drought impacts.

Natural enemies of plant pathogens might play an important role in controlling plant disease levels in natural and agricultural systems. Yet, plant pathogen–natural enemy interactions might be sensitive to climatic changes. Understanding the relationship between climate, plant pathogens and their natural enemies is thus important for developing climate-resilient, sustainable agriculture. To this aim, we recorded shade cover, daily minimum and maximum temperature, relative humidity, coffee leaf rust and its hyperparasite at 58 sites in southwestern Ethiopia during the dry and wet season for 2 years. Coffee leaf rust severity was positively related to the maximum temperature. Hyperparasite severity was higher when the minimum temperature was low (i.e. in places with cold night temperatures). While canopy cover did not have a direct effect on rust severity, it reduced rust severity indirectly by lowering the maximum temperature. Canopy cover had a direct positive effect on the hyperparasite severity during one surveying period. Synthesis and applications. Our findings highlight that coffee leaf rust and its hyperparasite are both affected by shade cover and temperature, but in different ways. On the one hand, these niche differences lead to the worrying prediction that levels of coffee leaf rust will increase, and its hyperparasite will decrease, with climate change. On the other hand, these niche differences between coffee leaf rust and its hyperparasite provide opportunities to develop strategies to manage the environment (such as shade cover and microclimate) in such a way that the rust is disfavoured and the hyperparasite is favoured.

The warming climate is having profound impacts on glacier dynamics and extents. To improve our predictions of future ice mass changes, we require an enhanced understanding of both past and present glacial processes. The physical properties and structure of glacial sediments and landforms aid reconstructions of past environments and ice dynamics on numerous scales. Traditionally, these factors have been studied using glacial geological techniques such as sedimentary logging. While this provides valuable in situ data, there are numerous limitations, namely the limited availability and spatial extent of exposures. In recent decades, near-surface geophysical techniques have gained in popularity within the fields of glaciology, geomorphology, and sedimentology. Geophysics offers a non-invasive means of obtaining spatially extensive data on substrate properties and architecture, however issues such as signal scattering and interpretation ambiguity in complex glaciated environments restrict its application. This thesis exemplifies how near-surface geophysical techniques can aid glacial landscape interpretations focusing on ground-penetrating radar, seismic refraction, and multi-channel analysis of surface waves. It explores the current limitations of the methods and outlines solutions to improve their applicability, in terms of geophysical campaign success, as well as uncertainty estimation and visualisation. The reliability of geophysical interpretations can be improved by including direct substrate observations in campaigns. Here, the benefits of performing detailed sediment logging alongside geophysical surveys are exemplified, together with descriptions and explanations of associated method adaptations. Through a combination of method updates and applied studies, this thesis highlights the great potential for geophysical techniques in improving our understanding of glacial processes and outlines potential avenues for further work in this area.

Recent studies have raised concerns regarding the reconstruction of glacier mass balance using tree-ring data. The method relies on a stable relationship between both variables and summer (June-August) or melt season (May-September) temperature. However, with recent anthropogenic climate change the stability of this relationship is challenged by both, a divergence between tree-ring and temperature, as well as mass balance and temperature data. Establishing to what extent this divergence influences the reconstruction of mass balance using tree-ring data is important to assess the future viability and applicability of the method. In this paper we analyze the relationship between the Tornetrask tree-ring and Storglaciaren mass balance records, their response to climate change, and investigate changes in the relationship. We provide evidence for a sensitivity loss in the Tornetrask record and quantify its impact on the reconstruction of summer mass balance of Storglaciaren. We find that by including years post 1980, the amplitude of reconstructed variability is reduced, but it remains possible to explain the variance of the record significantly. Our results suggest that for glaciers without an extensive mass balance record the applicability of the method is challenged.

Om eleverna ska få rätt bild av geografiämnets delar i närområdet, behöver de få genomföra fältstudier. De kan inte få all geografisk kunskap ur det den fakta som förmedlas i klassrummet, eftersom ämnet är komplext. Syftet med studien var därför att undersöka hur lärare kompletterar den klassrumsbaserade undervisningen med utomhuspedagogiska fältstudier och vad dessa bidrar med. Samt om det finns begränsningar kring att genomföra dessa. En kvalitativ metod tillämpades, där semistrukturerade intervjuer genomfördes med fem respondenter. Resultatet som framkommer i studien visar att lärare använder fältstudier som komplement och att de tycker de är viktiga, både för kunskapsinhämtning och elevernas minnesbilder. Detta då eleverna får förståelse för de mönster och samband som finns i utomhusmiljön. Det framkommer även att det finns en del begränsningar i form av ekonomi och elevgruppssammansättningar. Slutsatsen av detta tillsammans med relevant forskning, visar att det är gynnsamt att använda både klassrumsbaserat lärande och fältstudier i geografiundervisningen som genomförs i F-3. Dock skulle de intervjuade lärarna önskat att de kunde genomföra dessa oftare., 2024-01-12

This study aims to investigate and analyse the knowledge gap between the Swedish high school and geography syllabus, on one hand, and scientific research on the other. This study is emphasizing on the need for a future-oriented approach in the Swedish curriculum, which is needed to address future challenges. In this study the focus is directed towards climate and environmental education, where sustainable development is a key component of the current geography syllabus, in contrast of scientific research where climate emergency and the geological epoch Anthropocene makes the current knowledge. Utilizing discourse analysis to examine factors such as the underlying values, roles, and power of actors in the shaping process of educational documents, such as the policy and educational documents. The study is conducted in two sub-studies which will be conducted separately and later being compared to each other. The results of the two sub-studies revealed an existing knowledge gap and revealed the influence of politics and science on values, shaping attitudes by education. By applying Lindes (2021) curriculum codes, the analysis indicates a prevalence of the political code in the current curriculum, while Spratt´s (2022) scientific research aligns with the scientific-rational code. The conclusion drawn from this study is that an updated curriculum is essential to transform attitudes towards climate and environmental issues. The discourse analysis of the current curriculum emphasizes the prioritization of values over current knowledge, which has contributed to the planetary crisis that science has identified as a climate emergency.

Many rivers can shape their path through the landscape with erosion and deposition where the riverbed and riverbanks both shape the direction and energy of the flow. The river flow can erode the riverbanks and create meanders which is when the river creates bends in its path that become increasingly curved. Meanders are affected by natural aspects of the landscape but also by anthropogenic structures like dams. The Rönne river is the largest river in the region of Skåne in southern Sweden and along it is three major dams that act as barriers for fish species. These dams are scheduled to be removed in 2024. To estimate how the Rönne river may react to the removal of these dams, the river’s erosion, deposition, and stream width was studied for the years 1926-1934, 1960, 1970 and 2018. By understanding how the dams have affected the river, it may be possible to argue how the river will change after the dams are removed. Erosion was greatest downstream of the dams but changes to deposition and stream width did not follow the pattern indicative with dams. The dams were not the determining factor and other factors such as land use and surficial geology are more impactful to the morphological changes in the river. Issues with the method and used materials affected and created uncertainty with the results. Improvements and changes are therefore needed for the method and the materials to better determine how the Rönne river is affected by the studied dams.

Climate change jeopardizes human health, global biodiversity, and sustainability of the biosphere. To make reliable predictions about climate change, scientists use Earth system models (ESMs) that integrate physical, chemical, and biological processes occurring on land, the oceans, and the atmosphere. Although critical for catalyzing coupled biogeochemical processes, microorganisms have traditionally been left out of ESMs. Here, we generate a "top 10" list of priorities, opportunities, and challenges for the explicit integration of microorganisms into ESMs. We discuss the need for coarse-graining microbial information into functionally relevant categories, as well as the capacity for microorganisms to rapidly evolve in response to climate-change drivers. Microbiologists are uniquely positioned to collect novel and valuable information necessary for next-generation ESMs, but this requires data harmonization and transdisciplinary collaboration to effectively guide adaptation strategies and mitigation policy.

Water is a crucial resource that can unite or divide nations, but throughout history, people have generally cooperated to solve water-related issues. However, as freshwater scarcity intensifies due to climate shifts and escalating human demands, it is critical to identify water-related conflicts and cooperation dynamics. For instance, changes in water patterns, including floods, droughts, and dam construction to manage varying precipitation, could lead to increased competition and conflict over water resources. Effective water management and collaboration could help resolve these issues and foster peaceful water governance. The main aim of this thesis is to examine the connections between how humans, the climate, and changes in water have affected cooperation and conflicts over water. This research involves investigating the interactions between changes in freshwater availability, water-related events such as conflicts and cooperation, and changes in human activities and climate. The focus is mainly on global and regional large-scale levels, and the work comprises four parts: (i) a scoping review of previous scientific literature to identify important conflict factors and research gaps; (ii) hydrological modeling to determine the direction and magnitude of hydroclimatic change relating to human activities; (iii) creation of an updated water-related conflict and cooperation database and analysis of current trends; and (iv) analyses of how socio-economic and climatic factors affect water events and cooperation mechanisms behind successful conflict mitigation. The combined results from the four parts reveal that governance, policy, and climate change are important conflict factors worldwide. Agriculture emerges as particularly important in Africa and Asia, but there are regional variations in the importance of different conflict factors to these water conflicts. A significant research gap emerges for regions outside Africa and parts of Asia. This is problematic since

High-resolution unoccupied aerial vehicle (UAVs) data have alleviated the mismatch between the scale of ecological processes and the scale of remotely sensed data, while machine learning and deep learning methods allow new avenues for quantification in ecology. Ant nests play key roles in ecosystem functioning, yet their distribution and effects on entire landscapes remain poorly understood, in part because they and their mounds are too small for satellite remote sensing. This research maps the distribution and impact of ant mounds in a 20 ha treeline ecotone. We evaluate the detectability from UAV imagery using a deep learning model for object detection and different combinations of RGB, thermal and multispectral sensor data. We were able to detect ant mounds in all imagery using manual detection and deep learning. However, the highest precision rates were achieved by deep learning using RGB data which has the highest spatial resolution (1.9 cm) at comparable UAV flight height. While multispectral data were outperformed for detection, it allows for novel insights into the ecology of ants and their spatial impact on vegetation productivity using the normalized difference vegetation index. Scaling up, this suggests that ant mounds quantifiably impact vegetation productivity for up to 4% of our study area and up to 8% of the Betula nana vegetation communities, the vegetation type with the highest abundance of ant mounds. Therefore, they could have an overlooked role in nutrient-limited tundra vegetation, and on the shrubification of this habitat. Further, we show the powerful combination UAV multi-sensor data and deep learning for efficient ecological tracking and monitoring of mound-building ants and their spatial impact.

Vattenbruk har i Sverige och EU lyfts fram som hållbar matproduktion med stor potential för framtiden. Denna rapport fokuserar på det extraktiva vattenbruket, vilket innefattar odling av musslor, ostron, alger, sjöpung och andra arter som inte kräver tillförsel av foder eller närsalter. I nuläget är vattenbrukssektorn i Sverige förhållandevis liten, och för att vattenbruk ska bli en bärande del av svensk och europeisk matproduktion behöver vattenbrukssektorn växa.Det finns dock en rad hinder för utveckling av vattenbrukssektorn i Sverige. Ett betydande hinder är att konkurrensen om lämpliga ytor i havet är hög, vilket kan ge upphov till nya eller fördjupade intressekonflikter. Kustzonsplanering har identifierats som en central åtgärd för att hantera intressekonflikter, men tidigare studier visar att befintliga planer inte har resulterat i en proaktiv styrning av havsanvändningen. För att utveckla kunskapen om de hinder som vattenbrukssektorn står inför fokuserar denna rapport på relationen mellan vattenbruk och andra intressen, och då i synnerhet friluftsliv och båtliv, i och kring havet i Lysekilsområdet. Det handlar mer konkret om att undersöka och förstå hur involverade aktörer ser på intressekonflikten och eventuella möjligheter till samexistens och synergieffekter mellan vattenbruk och andra intressen. Med detta syfte har dokumentstudie av kustzonsplaner och tillståndsärenden samt intervjuer med involverade aktörer genomförts. Resultatet visar att kommunal kustzonsplanering och tillståndsprövningar av både länsstyrelse och domstol söker hantera och förebygga intressekonflikter genom att geografiskt separera olika intressen som antas vara motstående. Samtidigt framgår det av intervjuerna att intressekonflikten mellan vattenbruk och andra intressen inte uppfattas som omfattande i dagsläget. Detta kan troligen härledas till att vattenbruksverksamheten i det undersökta området fortfarande är relativt småskalig. Det finns dock en viss oro inför att en växande vatten, Aquaculture has been highlighted in Sweden and the EU as a sustainable food production method with significant potential for the future. This report focuses on extractive aquaculture, which includes the cultivation of mussels, oysters, algae, sea squirts, and other species that do not require supplemental feeding nor fertilizer. Currently, the aquaculture sector in Sweden is relatively small, and for aquaculture to become a significant part of Swedish and European food production, it needs to expand.There are several obstacles to the development of the aquaculture sector in Sweden. A significant hindrance is the high degree of competition for suitable marine areas, which can lead to new or intensified conflicts of interest. Coastal zone planning has been proposed as an essential tool for managing these conflicts, but previous studies have shown that existing plans have not resulted in proactive management of how the sea is utilized.To enhance our understanding of the challenges faced by the aquaculture sector, this report focuses on the relationship between aquaculture and other interests – in particular, outdoor recreation and boating in and around the sea in the Lysekil area. Specifically, it aims to investigate how involved stakeholders perceive the conflict of interest and explore potential opportunities for coexistence and synergies between aquaculture and other interests. The research includes document analysis of coastal zone plans and permit applications, as well as interviews with relevant stakeholders.The findings show that municipal coastal zone planning, along with permit assessments conducted by both the County Administrative Board and the court, attempts to manage and prevent conflicts of interest. This is pursued through the geographical separation of assumed opposing interests. However, the interviews indicates that the conflict of interest between aquaculture and other interests is not perceived as prominent at present. It is likely that the perceiv

Uncrewed aerial vehicles (UAVs) are frequently used in glaciological applications, among other things, for photogrammetric assessments of calving dynamics at glacier termini. However, UAVs are often limited by battery endurance and weight constraints on the scientific payload that can be added. At Sálajiegna, the largest freshwater calving glacier in Sweden, we explored the combined use of a versatile maritime robot (uncrewed surface vehicle, USV) and a UAV to characterise Sálajiegna's short-term and seasonal calving front dynamics and mass loss. For this, a photogrammetric payload suite was integrated into the USV. Consecutive USV surveys of Sálajiegna's front, followed by point cloud based calving detection and surface-reconstruction based volume quantification, allowed for a detailed description of calving-induced terminus changes and is hence suggested as a viable alternative to the differencing of digital elevation models. By combining USV and UAV measurements, we identify sectors of high and low calving activity, a calving front retreat of up to 56 m and a thinning rate in the terminus region of 5.4 cm d−1 during the summer of 2022., QC 20240701

Evaluating how land cover is being transformed is essential to identify patterns necessary to infer the change trajectories and the driving factors. This study considers the case of Nigeria, where various natural ecosystems are being converted and for which a current national scale assessment at high spatial resolution is lacking. Producing 30 m Landsat-based time-series data, we analyze change among land cover types (i.e. tree-covered area, grassland, wetland, waterbody, cropland, artificial surface, and otherland) across seven agroecological zones. The annual change intensity was assessed at multi-levels across two time-intervals (i.e. 2000–2013, 2013–2022). Distinguishing between natural land cover and human activity-related land-use, we estimate the extent of change signifying how humans have appropriated natural land cover. Insights from analysis at the interval level reveal that land transformation accelerated from 3.3% in 2000–2013 to 4.5% during 2013–2022 in all agroecological zones (e.g. rainforest, mangrove), except in Sudan savannah and Sahel savannah where speed was higher in 2000–2013 as grasslands were increasingly cultivated. Cropland expanded almost two-fold (22% to 37%), whereas tree-cover declined from 50% to 31% and wetland from 7% to 3.7% over the 23 years. Much loss of natural land cover (e.g. tree-cover, grassland, and wetland) to cropland occurred in 2000–2013 (22%) when most irrigation schemes in Nigeria were established. In contrast, the loss of natural land cover to settlement (0.9%) during 2000–2013 increased to 2.0% in 2013–2022. Of all agroecological zones, the mangrove zone was most disturbed as its persisting land cover areas reduced from 69% to 5% between 2000–2013 and 2013–2022. The amount of persisting land cover was highest in the Sudan savannah at 44% in 2000–2013 and 49% in 2013–2022. Processes of human-appropriated natural land cover in Nigeria are related to urbanization and cropland expansion into natural areas with some insta

Shore displacement has largely affected both the natural landscape and the humans within. This is especially true for Västergarn parish on Gotland, where low-lying plains make up large parts of the domain. Yet, the land–sea interaction of Västergarn, has not been studied closely for a long time. Through a comprehensive study, as well as a reexamination, of different sources and materials, this study aims to shed new light on the spatial distribution and chronology of Västergarn. To understand this, we need to get a scope of the extent of the sea. Previous research (e.g. Ilves & Darmark 2011; Mikołajczyk et al. 2015) has showed that phosphate analysis may help indicate the position of former shorelines. How can this, methodologically, be applied to phosphate-mapping carried out well over 50 years ago? This thesis does not aim to completely answer this question, but rather to analyze what went into determining a shore-level for 1000 AD during earlier research (e.g. Lundström 1979, 1981). Moreover, this study aims to critically examine the interplay between historical shore-levels and the built world within Västergarn. The Västergarn defensive wall and Paviken bay constitute the two main areas of study, owing to the pursuit of understanding the interplay between these two sites. Västergarn cannot be fully understood without also including the Kronholmen peninsula (formerly island, as the name suggests), why some attention is also directed towards this area., Strandförskjutningen har till stor del påverkat både naturlandskapet och människorna inom. Detta stämmer i synnerhet för Västergarns socken på Gotland, där i princip hela området är att betrakta som synnerligen låglänt. Ändå har relationen mellan land och hav i Västergarn, inte utforskats närmare på länge. Genom att inkludera och ompröva ett flertal olika källor och material, syftar denna studie till att på nytt belysa Västergarns rumsliga fördelning och kronologi. Tidigare forskning (se Ilves & Darmark 2011; Mikołajczyk et al. 2015) har visat på att analys fosfatvärden kan bära med sig insikt i forna strandlinjenivåer. Hur kan denna kunskap metodologiskt tillämpas på fosfatkarteringar som genomfördes för mer än 50 år sedan? Denna uppsats syftar inte till att fullständigt besvara denna fråga, men däremot att närma sig vad som legat till grund för att fastställa en strandnivå för 1000 e.Kr. under tidigare forskning (se Lundström 1979, 1981). Huvudfokus för denna studie är att kritiskt granska samspelet mellan historiska strandlinjenivåer och bebyggelse i Västergarn. Västergarnsvallen och Paviken utgör, i strävan efter att förstå relationen mellan dessa två platser, de huvudsakliga studieområdena. Västergarn kan dock inte förstås till fullo utan att även blicka mot halvön Kronholmen (tidigare ö, som namnet vittnar om), varför en viss uppmärksamhet också riktas mot detta område.

The main challenges for utilizing daily evapotranspiration (ET) estimation in the study area revolve around the need for accurate and reliable data inputs, as well as the interpretation of ET dynamics within the context of local agricultural practices and environmental conditions. Factors such as cloud cover, atmospheric aerosols, and variations in land cover pose challenges to the precise estimation of ET from remote sensing data. This research aimed to utilize Landsat 8 and 9 datasets from the 2022–23 period in the Udham Singh Nagar district to apply the modified Priestley-Taylor (MPT) model for estimating ET. An average ET was estimated 1.33, 1.57, 1.70, 2.99, and 3.20 mm day−1 with 0.29, 0.33, 0.41, 0.69, and 1.03 standard deviation for December, January, February, March, and April month, respectively. In the validation phase, a strong correlation was found between the evaporative fraction derived from MPT and that observed by lysimeter, with R2 = 0.71, mean biased error = 0.04 mm day−1, root mean squared error = 0.62 mm day-1 and agreement index of 0.914. These results collectively support the effectiveness of the MPT model in accurately estimating ET across Udham Singh Nagar district. In essence, this research not only confirms the MPT model’s capability in ET estimation but also offers detailed insights into the spatial and temporal fluctuations of energy fluxes and daily ET rates., Full text license: CC BY

Aim: How the ability of plants to move towards newly favourable habitats (dispersal limitation) impacts the change of biome distribution and transition under fast climate warming is still debated. Analysing vegetation change in the past may help to clarify the relative importance of underlying ecological processes such as climate, biotic interactions, and dispersal. In this study, we investigated how dispersal limitation affected the distribution of European forests in the last 18,000 years. Location: Southern and Central Europe. Taxon: Spermatophyta. Methods: Using the LPJ-GM 2.0 model (an extension of LPJ-GUESS), we simulated European vegetation from the end of the Last Glacial Maximum (18.5 ka) to the current time (0 ka). Using biome reconstructions from pollen data as reference, we compared the performance of two dispersal modes: with no migration constraints or seed limitation (free dispersal mode), and with plant establishment depending on seed dynamics and dispersal (dispersal limitation mode). Results: The model run, including migration processes, was better at capturing the post-glacial expansion of European temperate forests (and the longer persistence of boreal forests) than the setting assuming free dispersal, especially during periods of rapid warming. This suggests that a number of (temperate) tree taxa experienced delayed occupancy of climatically suitable habitats due to a limited dispersal capacity, i.e., post-glacial migration lags. Main Conclusions: Our results show that including migration processes in model simulations allows for more realistic reconstructions of forest patterns under rapid climate change, with consequences for future projections of carbon sequestration and climate reconstructions with vegetation feedback, assisted migration and forest conservation.

Significant progress in permafrost carbon science made over the past decades include the identification of vast permafrost carbon stocks, the development of new pan-Arctic permafrost maps, an increase in terrestrial measurement sites for CO2 and methane fluxes, and important factors affecting carbon cycling, including vegetation changes, periods of soil freezing and thawing, wildfire, and other disturbance events. Process-based modeling studies now include key elements of permafrost carbon cycling and advances in statistical modeling and inverse modeling enhance understanding of permafrost region C budgets. By combining existing data syntheses and model outputs, the permafrost region is likely a wetland methane source and small terrestrial ecosystem CO2 sink with lower net CO2 uptake toward higher latitudes, excluding wildfire emissions. For 2002–2014, the strongest CO2 sink was located in western Canada (median: −52 g C m−2 y−1) and smallest sinks in Alaska, Canadian tundra, and Siberian tundra (medians: −5 to −9 g C m−2 y−1). Eurasian regions had the largest median wetland methane fluxes (16–18 g CH4 m−2 y−1). Quantifying the regional scale carbon balance remains challenging because of high spatial and temporal variability and relatively low density of observations. More accurate permafrost region carbon fluxes require: (a) the development of better maps characterizing wetlands and dynamics of vegetation and disturbances, including abrupt permafrost thaw; (b) the establishment of new year-round CO2 and methane flux sites in underrepresented areas; and (c) improved models that better represent important permafrost carbon cycle dynamics, including non-growing season emissions and disturbance effects.