1.
Barrientos, Natalia, 1985-
(författare)
Arctic Ocean benthic foraminifera preservation and Mg/Ca ratios : Implications for bottom water palaeothermometry
2018
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Reconstructions of Arctic Ocean palaeotemperatures are needed to disentangle natural variability from anthropogenic changes and understand the role of ocean heat transport in forcing or providing feedbacks on Arctic climate change. Despite known complications with calcareous microfossil preservation in Arctic Ocean sediments, calcareous benthic foraminifera can be common in interglacial sequences. However, thus far they have been underutilized in palaeoceanographic studies. This thesis explores the application of the Mg/Ca palaeothermometry proxy for reconstructing bottom water temperatures (BWT) in the Arctic Ocean during the late Quaternary. This method, which is supported by previous empirical studies demonstrating a strong temperature control on trace Mg inclusion into foraminiferal shell calcite, has been applied in many ocean regions and time intervals. Until now its application in the Arctic Ocean has been sparingly explored.The results of this doctoral thesis are based on benthic foraminifera retrieved from marine sediment cores covering a wide geographical Arctic Ocean area including both the shallow and vast continental shelves and slopes to the intermediate-to-deep waters of the Lomonosov Ridge and Morris Jesup Rise. These provide the first benthic foraminifera Mg/Ca ratios from the central Arctic Ocean region. In the first study, mechanisms that could affect Mg incorporation in Arctic benthic foraminifera are investigated using oceanographic field data and six 'live' modern Arctic species (Elphidium clavatum, Nonionella labradorica, Cassidulina neoteretis, Oridorsalis tener, Cibicidoides wuellerstorfi and Quinqueloculina arctica). The result is new species-specific Mg/Ca–BWT field calibrations that provide important constraints at the cold end of the BWT spectrum (-2 to 1°C) (Paper I). Using the new Mg/Ca–BWT equation for E. clavatum, a palaeotemperature record was generated for the late Holocene (past ca. 4100 yr) from the western Chukchi Sea. The data showed BWT fluctuations from -2 to 1°C that are interpreted as showing pulses of warmer Pacific water inflow at 500–1000 yr periods, thus revealing multi-centennial variability in heat transport into the Arctic Ocean driven by low latitude forcings (Paper II). Complications with foraminiferal calcite preservation that limit Mg/Ca palaeothermometry in the Arctic were discovered and these are tackled in two additional papers. Anomalously high Mg content in benthic foraminifera from the central Arctic Ocean is linked to diagenetic contamination as a result of the unique oceanographic, sedimentary and geochemical environment (Paper III). Lastly, the dramatic post-recovery dissolution of foraminifera from a Chukchi Shelf sediment core during core storage is investigated and attributed to acidification driven by sulphide oxidation in this organic rich and calcite poor shelf setting (Paper IV).The findings of this thesis demonstrate that benthic foraminiferal Mg/Ca-palaeothermometry can be applied in the Arctic Ocean and capture small BWT change (on the order of -2 to 2°C) even at low temperatures. In practice, preservational complexities can be limiting and require special sample handling or analysis due to the high potential for diagenetic contamination in the central Arctic Ocean and rapid post coring calcite dissolution in the seasonally productive shelf seas. This Ph.D. project is a component of the multidisciplinary SWERUS-C3 (Swedish-Russian-US Arctic Ocean Climate-Cryosphere- Carbon Interactions) project that included an expedition with Swedish icebreaker Oden to the East Siberian Arctic Ocean.
2.
Hossain, Mohammed, 1960-
(författare)
Sustainable Arsenic Mitigation A Strategy for Scaling-up Safe Water Access : A Strategy for Scaling-up Safe Water Access
2015
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
In rural Bangladesh, the drinking water supply is mostly dependent upon manually operated hand pumped tubewells, installed by the local community. The presence of natural arsenic (As) in groundwater and its wide scale occurrence has drastically reduced the safe water access across the country and put tens of millions of people under health risk. Despite significant progress in understanding the source and distribution of As and its mobilization through sediment-water interactions, there has been limited success in mitigation since the problem was discovered in the country’s water supply in 1993. This study evaluated the viability of other kinds of alternative safe drinking water options and found tubewells are the most suitable due to simplicity and technical suitability, a wide acceptance by society and above all low cost for installation, operation and maintenance. During planning and decision making in the process of tubewell installation, depth of the tubewell is a key parameter as it is related to groundwater quality and cost of installation. The shallow wells (usually < 80m) are mostly at risk of As contamination. One mitigation option are deep wells drilled countrywide to depths of around 250 m. Compared to safe water demand, the number of deep wells is still very low, as the installation cost is beyond affordability of the local community, especially for the poor and disadvantaged section of the society. Using depth-specific piezometers (n=82) installed in 15 locations spread over the 410 km2 area of Matlab (an As-hot spot) in southeastern Bangladesh, groundwater monitoring was done over a 3 year period (pre- and post-monsoon for 2009-2011 period). Measurements were performed for hydrogeological characterization of shallow, intermediate deep and deep aquifer systems to determine the possibility of targeting safe aquifers at different depths as the source of a sustainable drinking water supply. In all monitoring piezometers, As was found consistently within a narrow band of oscillation probably due to seasonal effects. Hydrogeochemically, high-As shallow groundwaters derived from black sands are associated with elevated DOC, HCO3, Fe, NH4-N and PO4-P and with a relatively low concentration of Mn and SO4. Opposite to this, shallow aquifers composed of red and off-white sediments providing As-safe groundwater are associated with low DOC, HCO3, Fe, NH4-N and PO4-P and relatively higher Mn and SO4. Groundwaters sampled from intermediate deep and deep piezometers which were found to be low in As, are characterized by much lower DOC, HCO3, NH4-N and PO4-P compared to the shallow aquifers. Shallow groundwaters are mostly Ca-Mg-HCO3 type and intermediate deep and deep aquifers’ groundwaters are mostly Na-Ca-Mg-Cl-HCO3 to Na-Cl-HCO3 type.A sediment color tool was also developed on the basis of local driller’s color perception of sediments (Black, White, Off-white and Red), As concentration of tubewell waters and respective color of aquifer sediments. A total of 2240 sediment samples were collected at intervals of 1.5 m up to a depth of 100 m from all 15 nest locations. All samples were assigned with a Munsell color and code, which eventually led to identify 60 color varieties. The process continued in order to narrow the color choices to four as perceived and used by the local drillers for identification of the targeted As-safe aquifers. Munsell color codes assigned to these sediments render them distinctive from each other which reduces the risk for misinterpretation of the sediment colors. During the process of color grouping, a participatory approach was considered taking the opinions of local drillers, technicians, and geologists into account. In addition to the monitoring wells installed in the piezometer nests, results from 87 other existing drinking water supply tubewells were also considered for this study. A total of 39 wells installed in red sands at shallow depths producing As-safe water providing strong evidence that red sediments are associated with As-safe water. Average and median values were found to be less than the WHO guideline value of 10 μg/L. Observations for off-white sediments were also quite similar. Targeting off-white sands could be limited due to uncertainty of proper identification of color, specifically when day-light is a factor. Elevated Mn in red and off-white sands is a concern in the safe water issue and emphasizes the necessity of a better understanding of the health impact of Mn. White sediments in shallow aquifers are relatively uncommon and seemed to be less important for well installations. Arsenic concentrations in more than 90% of the shallow wells installed in black sands are high with an average of 239 μg/L from 66 wells installed in black sediments. It is thereby recommended that black sands in shallow aquifers must be avoided. This sediment color tool shows the potential for enhancing the ability of local tubewell drillers for the installation of As-safe shallow drinking water tubewells.Considering the long-term goal of the drinking water safety plan to provide As-safe and low-Mn drinking water supply, this study also pioneered hydrogeological exploration of the intermediate deep aquifer (IDA) through drilling up to a depth of 120 m. Clusters of tubewells installed through site optimization around the monitoring piezometer showed a similar hydrochemical buffer and proved IDA as a potential source for As-safe and low-Mn groundwater. Bangladesh drinking water standard for As (50 µg/L) was exceeded in only 3 wells (1%) and 240 wells (99%) were found to be safe. More than 91% (n=222) of the wells were found to comply with the WHO guideline value of 10 µg/L. For Mn, 89% (n=217) of the wells show the concentration within or below the previous WHO guideline value of 0.4 mg/L, with a mean and median value of 0.18 and 0.07 mg/L respectively. The aquifer explored in the Matlab area shows a clear pattern of low As and low Mn. The availability of similar sand aquifers elsewhere at this depth range could be a new horizon for tapping safe drinking water at about half the cost of deep tubewell installation.All findings made this study a comprehensive approach and strategy for replication towards As mitigation and scaling-up safe water access in other areas of Bangladesh and elsewhere having a similar hydrogeological environment.
3.
Linkhorst, Annika
(författare)
Greenhouse gas emission from tropical reservoirs : Spatial and temporal dynamics
2019
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
The emission of methane (CH4) and carbon dioxide (CO2) from reservoirs has been estimated to make up for about 1.3% of the global anthropogenic greenhouse gas emission. The impoundment of a river leads to the accumulation of sediment that is brought in from inflowing rivers, and the sediment organic matter is degraded to CH4 and CO2. CH4 is of particular concern as its global warming potential is 34 times stronger than that of CO2. In the tropics, high temperatures and high availability of fresh organic matter from high net primary production fuel CH4 and CO2 production. As the construction of hydropower plants is currently undergoing a boom, especially in the tropics, reservoir emission is probably bound to increase.The emission of CH4 and CO2 from reservoir surfaces is, however, highly variable, which makes current estimates uncertain. This thesis is built on the hypothesis that the spatial and temporal variability of greenhouse gas emission in tropical reservoirs, particularly of CH4 ebullition (the emission via gas bubbles), is so large that the sampling strategy affects whole-system estimates of greenhouse gas emission.This thesis shows that greenhouse gas emission from the four studied tropical reservoirs in Brazil varied greatly at different timescales – over 24 hours, between days and between seasons. Seasonal variability was identified as the most important temporal scale to be covered for CH4 ebullition inventories. In addition, the spatial variability of gas emission was large for all pathways. The variability of CH4 ebullition across space, for example, was estimated to be almost as large as its variability between seasons, and patterns of spatial variability in diffusive CH4 and CO2 emission differed between seasons. For both ebullition and diffusion, river inflow areas were prone to elevated greenhouse gas emission.This thesis shows that for retrieving solid emission estimates, there is no alternative to time-consuming measurements in the field. Measurements should be repeated at least once during each hydrological season (i.e. falling and rising water level). The seasonal surveys should cover space at a high resolution, including areas with and without river inflows, and different water column depths. CH4 ebullition made up for 60–99% of the total CO2-equivalent emission from the whole water surface of the studied reservoirs, with the highest contribution in the most productive reservoir. The most variable greenhouse gas emission pathway is therefore the most important one to be measured at appropriate resolution, particularly in productive reservoirs.
4.
Acosta Navarro, Juan Camilo, 1983-
(författare)
Anthropogenic influence on climate through changes in aerosol emissions from air pollution and land use change
2017
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Particulate matter suspended in air (i.e. aerosol particles) exerts a substantial influence on the climate of our planet and is responsible for causing severe public health problems in many regions across the globe. Human activities have altered the natural and anthropogenic emissions of aerosol particles through direct emissions or indirectly by modifying natural sources. The climate effects of the latter have been largely overlooked. Humans have dramatically altered the land surface of the planet causing changes in natural aerosol emissions from vegetated areas. Regulation on anthropogenic and natural aerosol emissions have the potential to affect the climate on regional to global scales. Furthermore, the regional climate effects of aerosol particles could potentially be very different than the ones caused by other climate forcers (e.g. well mixed greenhouse gases). The main objective of this work was to investigate the climatic effects of land use and air pollution via aerosol changes.Using numerical model simulations it was found that land use changes in the past millennium have likely caused a positive radiative forcing via aerosol climate interactions. The forcing is an order of magnitude smaller and has an opposite sign than the radiative forcing caused by direct aerosol emissions changes from other human activities. The results also indicate that future reductions of fossil fuel aerosols via air quality regulations may lead to an additional warming of the planet by mid-21st century and could also cause an important Arctic amplification of the warming. In addition, the mean position of the intertropical convergence zone and the Asian monsoon appear to be sensitive to aerosol emission reductions from air quality regulations. For these reasons, climate mitigation policies should take into consideration aerosol air pollution, which has not received sufficient attention in the past.
5.
Wallin, Marcus
(författare)
Evasion of CO₂ from streams : quantifying a carbon component of the aquatic conduit in the boreal landscape
2011
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Lateral export of carbon (C) from soils to running waters is a persistent pathway for C with terrestrial origin. This "aquatic conduit" might be especially important in boreal regions where a significant part of the global C stock is stored in the soil. Even though the awareness of the fate of terrestrially derived C is increasing in regional and global C budgets, the scarcity of data on the contribution of streams is widely acknowledged. In particular, the evasion (degassing) of gaseous C (i.e. CO₂ and CH₄) from the water surface of streams requires better characterization. This thesis aims to quantify the evasion of CO₂ from boreal streams within the 67 km2 Krycklan catchment, and explore the factors controlling this diffuse flux. All streams in the Krycklan catchment were consistently supersaturated in CO₂ and were hence a source for atmospheric CO₂ all year around. The source for this supersaturation of CO₂ was to a great extent explained by the export of respired C from the catchment soils. This was shown by exploring the export of dissolved inorganic carbon (DIC) across the soil/stream/atmosphere interfaces in a headwater catchment. The study also found that CO₂ evasion from the stream surface is a rapid process, and that much of the DIC leaving the soils is returned to the atmosphere as CO2 before leaving the headwaters. Evasion of CO₂ is dependent on the water-atmosphere concentration gradient, but also the gas exchange ability across the water-atmosphere interface (the gas transfer coefficient). The spatiotemporal variability of the gas transfer coefficient for carbon dioxide (KCO2) was found to be large, but the slope of the stream can be used to predict the spatial component of this variability. The positive relationship between KCO2 and stream section steepness was used to determine the spatial distribution of gas exchange ability for the entire stream network of forested Sweden. By combining concentration measurements and field-determined relationships with a high resolution digital elevation model (DEM) we were able to model the CO₂ evasion for each grid-cell of stream in the Krycklan catchment. Evasion of CO₂ from the entire stream network constituted a major component (<69 %) of the entire aquatic C flux. This study highlights the importance of including CO₂ evasion from streams in estimates of the aquatic conduit for carbon in boreal regions.
6.
Zetterberg, Therese
(författare)
Measured and modelled long-term effects of whole-tree harvest : impact on soil and surface water acid-base status in boreal forests
2015
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
This thesis examines the impact of whole-tree harvest (WTH) on soils and surface waters acid-base status in coniferous forests compared with conventional harvesting (CH). A combination of field observations (up to four decades) and dynamic modelling was used to describe the impact on soil calcium (Ca²⁺) pools and surface water acid neutralizing capacity (ANC). The studies were undertaken in northern and southern Sweden at sites belonging to the long-term wood fuel experiment (HELTRAD) and the ICP Integrated Monitoring (IM) programme. One of the most important findings was that WTH and CH caused large depletions (up to 60%) in soil exchangeable Ca²⁺ pools, circa 40 years after harvest. Despite these losses, tree growth and vitality has not yet been impaired. The results also implied that the fastest depletion rates occurred in CH-plots why soil Ca²⁺ pools between CH and WTH have become more similar with time. However, soil Ca²⁺ pools still remained significantly lower after WTH. Measured differences in soil solution showed that the impact of WTH on ANC was small (16 μEq l⁻¹) and temporary but site-specific. This difference was not large enough to counteract the natural recovery from acidification or lead to adverse ecological effects. The results indicate that WTH can have a large impact on soil exchangeable pools without causing surface water acidification in the absence of strong acid mobile anions. The rapidly declining soil Ca²⁺ pools may be of concern for sustainable forest management. However, trees will likely respond to lower Ca²⁺ availability by e.g. adjusting their uptake or develop biological feed-back mechanisms. The model predictions unanimously suggested that tree growth and net accumulation of nutrients in biomass caused large depletions in soil exchangeable Ca²⁺ pools and a decrease in stream ANC during the 19th and 20th centuries, exacerbated by acid deposition. Future predictions also suggested that these Ca²⁺ losses would continue accelerated by more intense harvesting practices. The impact on modelled stream ANC was smaller and depended on the concentrations of mobile anions. The empirical data pointed in the same direction as the MAGIC predictions, but the model exaggerated the impact. Until the discrepancy between measured and modelled impact have been resolved, interpretations changes related WTH using dynamic modelling or mass balance budget calculations should be done with caution.
7.
Dimberg, Peter H., 1985-
(författare)
Predictions Within and Across Aquatic Systems using Statistical Methods and Models
2015
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Aquatic ecosystems are an essential source for life and, in many regions, are exploited to a degree which deteriorates their ecological status. Today, more than 50 % of the European lakes suffer from an ecological status which is unsatisfactory. Many of these lakes require abatement actions to improve their status, and mathematical models have a great potential to predict and evaluate different abatement actions and their outcome. Several statistical methods and models exist which can be used for these purposes; however, many of the models are not constructed using a sufficient amount or quality of data, are too complex to be used by most managers, or are too site specific. Therefore, the main aim of this thesis was to present different statistical methods and models which are easy to use by managers, are general, and provide insights for the development of similar methods and models.To reach the main aim of the thesis several different statistical and modelling procedures were investigated and applied, such as genetic programming (GP), multiple regression, Markov Chains, and finally, well-used criteria for the r2 and p-value for the development of a method to determine temporal-trends. The statistical methods and models were mainly based on the variables chlorophyll-a (chl-a) and total phosphorus (TP) concentrations, but some methods and models can be directly transferred to other variables.The main findings in this thesis were that multiple regressions overcome the performance of GP to predict summer chl-a concentrations and that multiple regressions can be used to generally describe the chl-a seasonality with TP summer concentrations and the latitude as independent variables. Also, it is possible to calculate probabilities, using Markov Chains, of exceeding certain chl-a concentrations in future months. Results showed that deep water concentrations were in general closely related to the surface water concentrations along with morphometric parameters; these independent variables can therefore be used in mass-balance models to estimate the mass in deep waters. A new statistical method was derived and applied to confirm whether variables have changed over time or not for cases where other traditional methods have failed. Finally, it is concluded that the statistical methods and models developed in this thesis will increase the understanding for predictions within and across aquatic systems.
8.
Löfgren, Johan, 1983
(författare)
Local Sea Level Observations Using Reflected GNSS Signals
2014
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Sea level rise due to global warming is predicted to have a large impact on human society, especially for populations living in coastal regions and on islands. It is therefore of great importance to monitor the sea level and to increase the understanding of the local hydrodynamic and meteorological responses to a global sea level rise.The focus of this thesis is to estimate the local sea level using Global Navigation Satellite System (GNSS) signals reflected off the sea surface. These signals were recorded in two different ways using a GNSS tide gauge at the Onsala Space Observatory, consisting of standard geodetic-type commercially off-the-shelf GNSS equipment. First, the phase-delay of the reflected GNSS signals were recorded directly with a receiver connected to a nadir-looking antenna. Together with the phase-delay of the direct signals, recorded with a receiver connected to a zenith-looking antenna, standard geodetic analysis provided GNSS sea level observations. Second, the Signal-to-Noise Ratio (SNR) recorded with the receiver connected to the zenith-looking antenna, provided an indirect measurement of the reflected GNSS signals, as the reflected signals interfered with the direct GNSS signals and affected the recorded observables. From analysis of the multipath oscillations, an additional type of sea level observation was possible. Furthermore, the SNR-analysis method allowed other GNSS stations, located close to the ocean, in different parts of the world to become GNSS tide gauges.The GNSS-derived sea level from the GNSS tide gauge at the observatory was compared with independent observations of sea level from co-located traditional tide gauges, showing a high level of agreement with correlation coefficients of 0.89-0.99. The sea level results from the phase-delay analysis performed better with respect to the traditional sea level records than the results from the SNR-analysis. As an example, the Root-Mean-Square (RMS) differences from 1 month of observations between the GNSS-derived sea level (using frequency band L1) and the sea level from the co-located tide gauge were 3.2-3.5 cm and 4.0-4.7 cm for the phase-delay analysis and the SNR-analysis, respectively.Sea level results applying the SNR-analysis for data of 5 different GNSS stations around the world were compared to independent co-located traditional tide gauge records. The results showed RMS differences on the order of 6.2 cm for stations with low tidal ranges (up to 165 cm) and 43 cm for stations with high tidal ranges (up to 772 cm). In this case, an extended SNR-analysis approach was applied, modelling a time dependent sea level.
9.
Hylén, Astrid, 1991
(författare)
Nutrient dynamics in coastal and shelf oceans - sediments as a regulator of eutrophication feedbacks
2022
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Coastal and shelf systems are under increasing pressure from human activities. Many coastal systems currently suffer from excessive algae growth following increased nutrient input from land, a process called eutrophication. The algae eventually sink to the seafloor, where they are degraded, which consumes oxygen (O2). In severe cases, O2 can become depleted entirely, resulting in mass mortality of animals and substantial changes in the system’s chemical conditions. When the external nutrient input decreases, O2 conditions should improve. However, feedback mechanisms that strengthen eutrophication and O2-depletion can lead to non-linear recovery. Processes that occur in the seafloor account for a considerable part of this non-linearity, as the shallow water depth in coastal systems leads to a strong coupling between processes in the water column and the sediments. Although we know much about the processes that cause eutrophication, we lack detailed and mechanistic knowledge about many of the feedback mechanisms that keep systems in a eutrophic state. Methods to mitigate coastal eutrophication are being developed, but due to the non-linearity response of many systems, the results of restoration efforts are difficult to predict. A marine system that exhibits strong, non-linear eutrophication feedbacks is the Baltic Sea. Efforts to reduce the nutrient load to the Baltic Sea over the last decades have been successful, yet the system remains eutrophic and suffers from severe O2 depletion. The main basins of the Baltic Sea differ substantially in environmental conditions as well as input rates and sources of organic matter, nitrogen and phosphorus. This spatial variability makes the Baltic Sea ideal for assessing factors that affect organic matter and nutrient cycling in sediment, which can determine the recovery trajectory for eutrophic systems. In this thesis, I use the Baltic Sea as a study site to investigate the role of sedimentary feedback mechanisms that regulate coastal eutrophication. I show that the shuttling of sediment particles can redistribute organic matter from shallow to deep parts of basins. The reactivity of organic matter depends on the nature of the compound and its environment. Therefore, particle shuttling substantially affects the pattern of O2 consumption as well as degradation and burial of organic matter. I further show that natural oxygenation events can be insufficient to break the feedback between eutrophication and O2 depletion in long-term eutrophic systems where the sedimentary capacity to remove or retain nitrogen and phosphorus is decreased. Finally, I show that when placed in a suitable environment, mussel farms used for eutrophication mitigation only have a minor impact on the underlying sediment. However, in terms of eutrophication mitigation, other techniques may be more efficient than mussel farming. In conclusion, the results presented in this thesis inform us about sediment mechanisms that regulate eutrophication and can be used to find locally adapted solutions for systems around the world.
10.
Jaramillo, Fernando, 1977-
(författare)
Changes in the Freshwater System : Distinguishing Climate and Landscape Drivers
2015
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Freshwater is a vital resource that circulates between the atmosphere, the land and the sea. Understanding and quantifying changes to the partitioning of precipitation into evapotranspiration, runoff and water storage change in the landscape are required for assessing changes to freshwater availability. However, the partitioning processes and their changes are complex due to multiple change drivers and effects. This thesis investigates and aims to identify and separate the effects of atmospheric climate change and various landscape drivers on long-term freshwater change. This is done based on hydroclimatic, land-use and water-use data from the beginning of the twentieth century up to present times and across different regions and scales, from catchment to global. The analyzed landscape drivers include historic developments of irrigated and non-irrigated agriculture and flow regulation. The thesis uses and develops further a data-motivated approach to interpret available hydroclimatic and landscape data for identification of water change drivers and effects, expanding the approach application from local to continental and global scales. Based on this approach development, the thesis identifies hydroclimatic change signals of landscape drivers against the background of multiple coexisting drivers influencing worldwide freshwater change, within and among hydrological basins. Globally, landscape drivers are needed to explain more than 70% of the historic hydroclimatic changes, of which a considerable proportion may be directly human-driven. These landscape- and human-driven water changes need to be considered and accounted for also in modeling and projection of changes to the freshwater system on land.
