Search

Only a few localised ice streams drain most of the ice from the Greenland Ice Sheet. Thus, understanding ice stream behaviour and its temporal variability is crucially important to predict future sea-level change. The interior trunk of the 700 km-long North-East Greenland Ice Stream (NEGIS) is remarkable due to the lack of any clear bedrock channel to explain its presence. Here, we present a 3-dimensional analysis of the folding and advection of its stratigraphic horizons, which shows that the localised flow and shear margins in the upper NEGIS were fully developed only ca 2000 years ago. Our results contradict the assumption that the ice stream has been stable throughout the Holocene in its current form and show that upper NEGIS-type development of ice streaming, with distinct shear margins and no bed topography relationship, can be established on time scales of hundreds of years, which is a major challenge for realistic mass-balance and sea-level rise projections.

Renewable fuels for transport are needed to reach future climate targets. However, the potential future role of different biofuels, hydrogen, and electrofuels (produced by electricity, water, and CO2) in different transportation sectors remains uncertain. Increased knowledge about the preconditions for different renewable fuels for road and air transport to contribute to the transformation of the transport sector is needed to ensure the transformation is done in a climate- and cost-effective way. The CO2 abatement cost, i.e., the cost of reducing a certain amount of greenhouse gas (GHG) emissions is central from both a societal and business perspective, the latter partly due to the design of the Swedish reduction obligation system. The abatement cost of a specific fuel value chain depends on the fuel production cost and the GHG reduction provided by the fuel. This report provides an updated summary of the CO2 abatement costs for various types of biofuels and electrofuels for road transport and aviation, relevant in a Swedish context. Fuel production costs and GHG performance (well to wheel) for the selected renewable fuel pathways are mapped based on published data. The estimated CO2 abatement cost ranges from -0.37 to 4.03 SEK/kg CO2-equivalent. Methane from anaerobic digestion of sewage sludge and ethanol from fermentation of sugarcane and maize end up with negative CO2 abatement cost given the assumptions made, meaning it is more economically beneficial to use than its fossil counterpart. Electrofuels pathways (particularly diesel and aviation fuels) have, on the other hand, relatively high CO2 abatement costs. Also, so-called bio-electrofuels produced from biogenic excess CO2 from biofuel production and electricity linked to biofuel production generally have higher CO2 abatement costs than the corresponding forest biomass-based biofuel pathway. For forest biomass-based biofuels, bio-electrofuels and electrofuels, methanol, and methane pathways in general have so, Commissioned by: Statens Energimyndighet

I den här rapporten presenteras en kartläggning av styrmedel för elektrifiering av vägtransporter, sjöfart och arbetsmaskiner. Rapporten är beställd av Naturvårdsverket och genomförd av IVL Svenska Miljöinstitutet. I kartläggningen har vi fokuserat på nationella styrmedel med en direkt påverkan på elektrifieringen. Huvudfokus har varit nordiska länder (Norge, Finland och Danmark) men vissa utblickar har gjorts när det funnits ett värde i att hitta fler exempel. Sverige har inte ingått i kartläggningen.De styrmedel som beskrivits innefattar stimulanser för köp av fordon, farkoster och arbetsmaskiner, stimulanser för drift och innehav, administrativa regler som syftar till att underlätta användning av eldrivna alternativ, upphandlingskrav samt stöd, krav och satsningar kopplat till laddinfrastruktur. Vi har både inkluderat nu gällande styrmedel samt styrmedel som av regeringar planeras men som ännu inte införts. I vissa fall har vi också beskrivit styrmedel som avskaffats.I kartläggningen har vi inte inkluderat styrmedel med en indirekt påverkan på elektrifieringen av de tre segmenten, exempelvis koldioxidskatter eller satsningar på elproduktion och elnät. Vi har heller inte tittat på styrmedel eller andra satsningar på kommunal nivå, regional nivå eller EU-nivå.För personbilar visar kartläggningen att det finns en stor bredd av styrmedel samtidigt som flera länder har fasat ut eller rentav avskaffat vissa styrmedel. En viktig iakttagelse här är hur olika styrmedel påverkar flöden av elbilar på andrahandsmarknaden, där Sverige länge haft problem med att många elbilar exporteras.Kartläggningen av styrmedel för tunga vägtransporter visar att flera länder har stöd både för inköp av ellastbilar och premierar drift av ellastbilar genom nedsättning i avståndsbaserade skatter. För sjöfart visar kartläggningen att relativt få länder har infört styrmedel för transportslaget. Dock utmärker sig Norge genom införandet av investeringsstöd, upphandlingskrav och en nationell handli, In this report, a survey of policies for the electrification of road transport, maritime transport, and working machinery is presented. The report was commissioned by the Swedish Environmental Protection Agency and carried out by the IVL Swedish Environmental Research Institute.In the survey, we have focused on national policies with a direct impact on electrification. The main focus has been on the Nordic countries (Norway, Finland, and Denmark), but some comparisons have been made when there was value in finding more examples. Sweden has not been included in the survey. The policies described include incentives for the purchase of vehicles, vessels, and machinery, incentives for operation and ownership, administrative regulations aimed at supporting the use of electric alternatives, procurement requirements, as well as support, requirements, and investments related to charging infrastructure. We have included both current policies and policies that have been decided but not yet implemented. In some cases, we have also described policies that have been discontinued.In the survey, we have not examined policies with an indirect impact on electrification of these three segments, such as carbon dioxide taxes or investments in electricity production and grids. We have also not looked at policies or other initiatives at municipal, regional, or EU levels.For passenger cars, the survey shows that there is a wide range of policies, while several countries have phased out or even abolished certain policies. An important observation here is how different policies affect the flow of electric cars in the second-hand market, where Sweden has long struggled with the export of many electric cars.The survey of policies for heavy road transport shows that several countries provide support for the purchase of electric trucks and incentivize the operation of electric trucks through reductions in distance-based taxes.For shipping, the survey shows that relatively few countries have int

We present a high-resolution airborne radar data set (EGRIP-NOR-2018) for the onset region of the Northeast Greenland Ice Stream (NEGIS). The radar data were acquired in May 2018 with the Alfred Wegener Institute's multichannel ultra-wideband (UWB) radar mounted on the Polar 6 aircraft. Radar profiles cover an area of ∼24 000 km2 and extend over the well-defined shear margins of the NEGIS. The survey area is centered at the location of the drill site of the East Greenland Ice-Core Project (EastGRIP), and several radar lines intersect at this location. The survey layout was designed to (i) map the stratigraphic signature of the shear margins with radar profiles aligned perpendicular to ice flow, (ii) trace the radar stratigraphy along several flow lines, and (iii) provide spatial coverage of ice thickness and basal properties. While we are able to resolve radar reflections in the deep stratigraphy, we cannot fully resolve the steeply inclined reflections at the tightly folded shear margins in the lower part of the ice column. The NEGIS is causing the most significant discrepancies between numerically modeled and observed ice surface velocities. Given the high likelihood of future climate and ocean warming, this extensive data set of new high-resolution radar data in combination with the EastGRIP ice core will be a key contribution to understand the past and future dynamics of the NEGIS. The EGRIP-NOR-2018 radar data products can be obtained from the PANGAEA data publisher (https://doi.pangaea.de/10.1594/PANGAEA.928569; Franke et al., 2021a).

Ren HVO, alltså HVO100, används av många upphandlare, transportköpare och transportbolag för att minska sina växthusgasutsläpp och leva upp till sina klimatåtaganden. I nuläget finns dock flera osäkerhetsfaktorer kopplat till marknaden för HVO100. Inte minst är en sådan faktor ovissheten i vad som sker med skattebefrielsen för rena och höginblandade biodrivmedel från 1 januari 2023 då statsstödsgodkännandet från EU-kommissionen löper ut. Aviserade förändringar av reduktionsplikten från 1 januari 2024 kan också få följder. Hur dessa faktorer, tillsammans med andra faktorer, kommer påverka HVO100-marknaden är i nuläget osäkert, vilket skapar ovisshet för alla som använder HVO100 för att minska sin klimatpåverkan. På uppdrag av Trafikverket har IVL Svenska Miljöinstitutet genomfört en studie av marknaden för HVO100 där både dagens marknad och framtida utveckling analyserats. Studien baseras primärt på intervjuer med ledande aktörer på drivmedelsmarknaden, primärt med leverantörer men även med producenter. Flera aspekter av marknaden har studerats, inklusive prisbild, tillgång och geografisk fördelning. Dessutom har framtida utveckling analyserats genom fyra olika styrmedelsscenarier. Scenarierna skiljer sig åt avseende skattebefrielsen, huruvida rena och höginblandade flyttas in i reduktionsplikten samt reduktionspliktens nivåer. En kortare analys av RME100/B100, det vill säga rapsbaserad biodiesel, har också genomförts. Priset för HVO100 har sedan reduktionspliktens införande legat ca 1-2 kr över priset för vanlig diesel. Detta har dock förändrats under 2022. Såväl innan som efter Rysslands invasion av Ukraina har både priset och prisskillnaden gentemot vanlig diesel fluktuerat. I nuläget är prisskillnaden ca 5 kr. Flera faktorer har bidragit till detta. Både ökad efterfrågan och att Tyskland under senaste året höjt sanktionsavgiften för att inte leva upp till reduktionsplikten sägs ha haft stor betydelse. RME100/B100 sticker ut i jämförelse då priset i nuläget är ca

Background and objectives In 2020, a wide range of hygiene measures was implemented to mitigate infections caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In consequence, pulmonary infections due to other respiratory pathogens also decreased. Here, we evaluated the number of bacterial and viral meningitis and encephalitis cases during the coronavirus disease 2019 (COVID-19) pandemic. Methods In a multicentre retrospective analysis of data from January 2016 until December 2020, numbers of patients diagnosed with bacterial meningitis and other types of CNS infections (such as viral meningitis and encephalitis) at 26 German hospitals were studied. Furthermore, the number of common meningitis-preceding ear-nose-throat infections (sinusitis, mastoiditis and otitis media) was evaluated. Results Compared to the previous years, the total number of patients diagnosed with pneumococcal meningitis was reduced (n = 64 patients/year in 2020 vs. n = 87 to 120 patients/year between 2016 and 2019, all p < 0.05). Additionally, the total number of patients diagnosed with otolaryngological infections was significantly lower (n = 1181 patients/year in 2020 vs. n = 1525 to 1754 patients/year between 2016 and 2019, all p < 0.001). We also observed a decline in viral meningitis and especially enterovirus meningitis (n = 25 patients/year in 2020 vs. n = 97 to 181 patients/year between 2016 and 2019, all p < 0.001). Discussion This multicentre retrospective analysis demonstrates a decline in the number of patients treated for viral and pneumococcal meningitis as well as otolaryngological infections in 2020 compared to previous years. Since the latter often precedes pneumococcal meningitis, this may point to the significance of the direct spread of pneumococci from an otolaryngological focus such as mastoiditis to the brain as one important pathophysiological route in the development of pneumococcal meningitis.

The North East Greenland Ice Stream clearly stands out in the surface velocity field of the ice flow of Greenland, with its sharp and narrow shear margins visible in the flow field almost up to the central divide. While the current extent and strength of the streaming can be determined from remotely sensed velocities of the ice surface, it is less known how the ice stream is affecting the deeper layers of ice in its catchment area, and how it may have evolved over time. The deformation of the ice due to streaming can be made visible by mapping the distortion of the isochronous stratigraphy of the ice. This has been done by an airborne radar survey centering on the location of the EGRIP drilling camp, carried out with the ultra wide band radar system (AWI UWB). The dense grid of profiles arranged mainly perpendicular to the ice flow reveals the imprint that the strong shearing leaves within the layering of the ice. Although the layers are tightly folded and distorted within the shear zones, it is possible to continuously trace reflections within the upper half of the ice column throughout the entire survey area. It can be shown that the intensity of the folding is linked to the strain rate field derived from the surface velocities, and that the deformation history of the ice is preserved in the folded layers, even after it is no longer affected by high strain rates. The advection patterns of the mapped stratigraphic features reveal how the streaming of the ice and the resulting local changes of surface topography may have affected the inflow into the stream and the position of the shear margins over time.

The ice stream geometry and large ice surface velocities at the onset region of the Northeast Greenland Ice Stream (NEGIS) are not yet well reproduced by ice sheet models. The quantification of basal sliding and a parametrization of basal conditions remains a major gap. In this study, we assess the basal conditions of the onset region of the NEGIS in a systematic analysis of airborne ultra‐wideband radar data. We evaluate basal roughness and basal return echoes in the context of the current ice stream geometry and ice surface velocity. We observe a change from a smooth to a rougher bed where the ice stream widens, and a distinct roughness anisotropy, indicating a preferred orientation of subglacial structures. In the upstream region, the excess ice mass flux through the shear margins is evacuated by ice flow acceleration and along‐flow stretching of the ice. At the downstream part, the generally rougher bed topography correlates with a decrease in flow acceleration and lateral variations in ice surface velocity. Together with basal water routing pathways, this hints to two different zones in this part of the NEGIS: the upstream region collecting water, with a reduced basal traction, and downstream, where the ice stream is slowing down and is widening on a rougher bed, with a distribution of basal water toward the shear margins. Our findings support the hypothesis that the NEGIS is strongly interconnected to the subglacial water system in its onset region, but also to the subglacial substrate and morphology.

We present new high-resolution snow depth data on Arctic sea ice derived from airborne microwave radar measurements from the IceBird campaigns of the Alfred Wegener Institute (AWI) together with a new retrieval method using signal peakiness based on an intercomparison exercise of colocated data at different altitudes. We aim to demonstrate the capabilities and potential improvements of radar data, which were acquired at a lower altitude (200 ft) and slower speed (110 kn) and had a smaller radar footprint size (2-m diameter) than previous airborne snow radar data. So far, AWI Snow Radar data have been derived using a 2-18-GHz ultrawideband frequency-modulated continuous-wave (FMCW) radar in 2017-2019. Our results show that our method in combination with thorough calibration through coherent noise removal and system response deconvolution significantly improves the quality of the radar-derived snow depth data. The validation against a 2-D grid of in situ snow depth measurements on level landfast first-year ice indicates a mean bias of only 0.86 cm between radar and ground truth. Comparison between the radar-derived snow depth estimates from different altitudes shows good consistency. We conclude that the AWI Snow Radar aboard the IceBird campaigns is able to measure the snow depth on Arctic sea ice accurately at higher spatial resolution than but consistent with the existing airborne snow radar data of NASA Operation IceBridge. Together with the simultaneous measurements of the total ice thickness and surface freeboard, the IceBird campaign data will be able to describe the whole sea-ice column on regional scales.