Northern Canada Research Articles

Examining the Viability of the World’s Busiest Winter Road to Climate Change Using a Process-Based Lake Model

AbstractWinter roads play a vital role in linking communities and building economies in the northern high latitudes. With these regions warming 2–3 times faster than the global average, climate change threatens the long-term viability of these important seasonal transport routes. We examine how climate change will impact the world’s busiest heavy-haul winter road—the Tibbitt to Contwoyto Winter Road (TCWR) in northern Canada. The FLake freshwater lake model is used to project ice thickness for a lake at the start of the TCWR—first using observational climate data, and second using modeled future climate scenarios corresponding to varying rates of warming ranging from 1.5° to 4°C above preindustrial temperatures. Our results suggest that 2°C warming could be a tipping point for the viability of the TCWR, requiring at best costly adaptation and at worst alternative forms of transportation. Containing warming to the more ambitious temperature target of 1.5°C pledged at the 2016 Paris Agreement may be the only way to keep the TCWR viable—albeit with a shortened annual operational season relative to present. More widely, we show that higher regional winter warming across much of the rest of Arctic North America threatens the long-term viability of winter roads at a continental scale. This underlines the importance of continued global efforts to curb greenhouse gas emissions to avoid many long-term and irreversible impacts of climate change.

A Hotly Contested Affair: Hockey in Canada. The National Game in Documents

There was a time in the not-so-distant past when Canada's relationship with hockey was tacitly understood but also academically underexamined. University-employed historians in Canada focused on more traditionally acceptable explorations like statecraft and nation-building. The Canadian public seemed contented with surface-level treatments and hagiographies of the game they loved. The life stories of their hockey heroes that supported the mythologies of the sport seemed to support the old adage from the food industry—you are better off not knowing how the sausage is made. We can be thankful that those simplistic offerings have yielded the stage to the more analytical approaches provided by scholars and thoughtful hockey players such as Ken Dryden. The literary canon has been substantially bolstered with critical investigations of league formation, race, gender, masculinity, ethnicity, and other important dimensions of consideration.Andrew Holman has been a key contributor to the field, and A Hotly Contested Affair casts him in the roles of both editor and writer, as his commentaries contextualize the collection. The ingredient that establishes A Hotly Contest Affair as unique is its inclusion of copious primary sources. These materials are not simply included in an appendix but are prominent elements in each chapter. Holman begins each section with a well-crafted synthesis that provides the appropriate background to understand the offering of primary documents that serve as the chapter's focal point. These sources are not dissected or curated by Holman but offered up whole, trusting the reader to pull what is necessary from the archival materials. Holman does provide informational footnotes to assist the reader further from a knowledge perspective but does not try to analyze the documents or flavor the reader's interpretation. The primary documents in A Hotly Contested Affair are wide-ranging and, as samples, include the West Ottawa District Girls Hockey Rules from 1972; telegraph bulletins produced by the Canadian Northern Telegraph Company for the Edmonton Hockey Club-versus-Montreal Wanderers Stanley Cup challenge from 1908; and Newsy Lalonde's contract with the Saskatoon Crescents for the 1922–23 season. Not every reader will find each source equally compelling, but there is such a diversity in Holman's collection that there appears to be something for everyone. It is truly an inspired idea for a hockey history book, although this work is so much more than that. Beyond the novel approach is the exquisite execution.In terms of contents, A Hotly Contest Affair explores ten topics, each given its own chapter. These themes are central to Canadians’ connection with hockey, both in a historical context and a more modern reimagining of the sport. The chapter titles are fairly self-explanatory: “An Evolutionary Game,” “A National Banner,” “An Arena for Commerce,” “A Cultural Problem,” “An Essentially Violent Game,” “A Quest for Order,” “A Question of Character,” “Hockey Talk,” “Communicating the Game,” “Race and Social Order,” “A Gendered Endeavour,” “Women's and Girl's Hockey,” and “An International Calling Card.” It is a comprehensive approach, and, if one could quibble, and often reviewers do, it would be over a lack of exploration into regionalism. This subject receives indirect treatment throughout the collection, however, so it is not an omission in the strictest sense.It was unclear who is the target audience for A Hotly Contested Affair. To be sure, university instructors teaching courses dedicated to exploring hockey would find this new offering quite valuable, perhaps not as a traditional textbook but more as a reader. The generously supplied primary documents could create an enriched learning experience wherein students could take a more active role in assessment and analysis. Whether A Hotly Contested Affair is well suited to a more general readership of enthusiasts is more difficult to know. The material is quite accessible thanks to Holman's prose, but hockey fans can be comfortable in the perfunctory (hence, the continued common usage of Original Six) and maybe would not gravitate toward a volume like this one, loaded with archival material—no matter how splendid. That matter, in all likelihood, is the purview of marketers, not reviewers.On balance, Holman's contribution is significant, and an argument can be made that A Hotly Contested Affair is the most important book that examines the relationship between Canada and hockey since Richard Gruneau and David Whitson's oft-cited Hockey Night in Canada: Sports, Identities and Cultural Politics published in 1994.

Undergraduate nursing students' perceptions about creating culturally safe classrooms: Living the epistemology, ontology and pedagogy

Cultural Safety is a means of empowerment through antiracist actions, decolonising praxis, an understanding of the effects of a colonial history, and reconciliation to an equitable and inclusive place. The purpose of this paper is to share the perceptions of undergraduate students in northern Canada about the creation of culturally safe classrooms. A secondary analysis was conducted on archived data from undergraduate nursing student-led research. The findings illuminated four themes: sharing with genuineness, disrupting dissonance, addressing history and transforming through relationality. The themes inform a model that offers a beginning understanding of how culturally safe classrooms transpired in the Canadian north to enable students to become inclusive, relational, critical, and informed.

Variations in mineralogy of dust in an ice core obtained from northwestern Greenland over the past 100 years

Abstract. Our study is the first to demonstrate a high-temporal-resolution record of mineral composition in a Greenland ice core over the past 100 years. To reconstruct past variations in the sources and transportation processes of mineral dust in northwestern Greenland, we analysed the morphology and mineralogical composition of dust in the SIGMA-D ice core from 1915 to 2013 using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results revealed that the ice core dust consisted mainly of silicate minerals and that the composition varied substantially on multi-decadal and inter-decadal scales, suggesting that the ice core minerals originated from different geological sources in different periods during the past 100 years. The multi-decadal variation trend differed among mineral types. Kaolinite, which generally formed in warm and humid climatic zones, was abundant in colder periods (1950–2004), whereas mica, chlorite, feldspars, mafic minerals, and quartz, which formed in arid, high-latitude, and local areas, were abundant in warmer periods (1915–1949 and 2005–2013). Comparison to Greenland surface temperature records indicates that multi-decadal variation in the relative abundance of these minerals was likely affected by local temperature changes in Greenland. Trajectory analysis shows that the minerals were transported mainly from the western coast of Greenland in the two warming periods, which was likely due to an increase in dust sourced from local ice-free areas as a result of shorter snow/ice cover duration in the Greenland coastal region during the melt season caused by recent warming. Meanwhile, ancient deposits in northern Canada, which were formed in past warmer climates, seem to be the best candidate during the colder period (1950–2004). Our results suggest that SEM–EDS analysis can detect variations in ice core dust sources during recent periods of low dust concentration.

Simultaneous monitoring of vegetation dynamics and wildlife activity with camera traps to assess habitat change

AbstractVegetation phenology and productivity drive resource use by wildlife. Vegetation dynamics also reveal patterns of habitat disturbance and recovery. Monitoring these fine‐scale vegetation patterns over large spatiotemporal extents can be difficult, but camera traps (CTs) commonly used to survey wildlife populations also collect data on local habitat conditions. We used CTs (n = 73) from 2016 to 2019 to assess impacts of habitat change in a boreal landscape of northern Canada, where seismic lines for petroleum exploration disturbed wildlife habitat and prompted vegetation restoration efforts. First, we quantified vegetation dynamics from CTs, comparing them to satellite‐based estimates that are typically used to monitor vegetation at broad spatial scales. We then used understory phenology and productivity estimated from CT time‐lapse images to assess vegetation recovery on seismic lines. Finally, we related vegetation dynamics with the habitat use of three wildlife species: sandhill cranes Grus canadensis, woodland caribou Rangifer tarandus, and white‐tailed deer Odocoileus virginianus. CTs provided unique insight into vegetation dynamics that were different from signals measured by satellites, with temporally inconsistent and even some negative correlations between CT and satellite metrics. We found some indication of vegetation recovery on seismic lines that had received restoration treatment, with understory patterns more similar to undisturbed habitat than to seismic lines that did not receive restoration treatment. CTs also provided inferences about wildlife activity related to vegetation resources, which approaches using satellite data failed to detect. Wildlife habitat use tracked vegetation phenology, but did not always increase with vegetation productivity at weekly, 16‐day, or annual intervals. Instead, associations with vegetation productivity depended on species, temporal scale, and productivity metrics. Given the widespread and growing use of CTs to monitor terrestrial wildlife, we recommend their use to simultaneously monitor habitat conditions to better understand the mechanisms that govern wildlife habitat use in changing environments.

Changes in floodplain regimes over Canada due to climate change impacts: Observations from CMIP6 models

With the recent Coupled Model Intercomparison Project Phase 6 (CMIP6), water experts and flood modellers are curious to explore the efficacy of the new and upgraded climate models in representing flood inundation dynamics and how they will be impacted in the future by climate change. In this study, for the first time, we consider the latest group of General Circulation Models (GCMs) from CMIP6 to examine the probable changes in floodplain regimes over Canada. A set of 17 GCMs from Shared Socioeconomic Pathways (SSPs) 4.5 (medium forcing) and 8.5 (high end forcing) common to historical (1980 to 2019), near-future (2021 to 2060), and far-future (2061 to 2100) time-periods are selected. A comprehensive framework consisting of hydrodynamic flood modelling, and statistical experiments are put forward to derive high-resolution Canada-wide floodplain maps for 100 and 200-yr return periods. The changes in floodplain regimes for the future periods are analyzed over drainage basin scale in terms of (i) changes in flood inundation extents, (ii) changes in flood hazards (high and very-high classes), and (iii) changes in flood frequency. Our results show a significant rise (>30%) in flood inundation extents in the future periods; particularly intense over western and eastern regions. The flood hazards are expected to cover ~16% more geographical area of Canada. We also find that large areas in northern and western Canada and a few spots in the eastern parts of Canada will be getting flooded more frequently compared to the historical period. The observations derived from this study are vital for enhancing flood preparedness, optimal land-use planning, and refurbishing both structural and non-structural flood control options for improved resilience. The study instills new knowledge on revamping the existing flood management approaches and adaptation strategies for future protection.

Responding to COVID-19: Contextual, Pedagogical, and Experiential Considerations from Canadian Northern Postsecondary Educators

The COVID-19 pandemic forced the closure of face-to-face classes in a northern Canadian college in March 2020. Educators and staff went into rapid response mode to continue teaching and supporting students from a distance. Critical reflections were written by the authors to summarize their responses to teaching and learning during the early phases of the pandemic. These reflections were themed, considered individually and collectively, then analyzed and synthesized. In this paper, critical reflection is used as an educational process within the context of critical constructivism and transformative paradigms. We share how teaching during the pandemic solidified our commitment to students and cemented our critical pedagogy by thinking and acting critically to assist students with this disruption in their education. Equipped with these capabilities, educators are empowered to work with students to problem solve and transform our educative lives for a just society. An inter-professional opportunity across programs, spurred by the pandemic, meets organizational strategic directions and fosters a promising relationality. Increased territorial and local technological supports and internal professional development is needed to solidify the immense prospects for distance education as the College transitions to a polytechnic university.

Investigating Standards for Small Water and Wastewater Systems in Northern Canada

Research investigating the potential of standards for the build, operation, and maintenance phases of small water and wastewater systems in the Canadian North was conducted to identify opportunities for standards to help ensure safe, accessible, and high-quality drinking water and sanitation for all northerners. This involved a review of literature, a survey of northern water system users and practitioners, and key informant interviews. The study highlights a general trend of low adaptation to local conditions for standardization documents on many technical topics in northern Canada. A number of major themes and corresponding recommendations are subsequently drawn with respect to potential for standardization efforts. Of these, training and certification/classification were identified as a key area that has many gaps, challenges, and potential opportunities with respect to the use of standardized procedures for small-scale water and wastewater systems. Subsequently, this is also identified as the area where standardization efforts may have the broadest social benefit, urgency, as well as potential feasibility.

The role of cultural heritage in the geopolitics of the Arctic: the example of Franklin’s lost expedition

Sir John Franklin’s ships departed from Greenhithe port in Great Britain (1845) with the aim of discovering the Northwest Passage in what is now Canada. During their journey, both ships got stuck in ice near King William Island and eventually sank. Over time, searches were held in order to find both wrecks. More recently, under the Conservative Government of Stephen Harper (2006–2015) there was renewed interest regarding what is now referred to as Franklin’s lost expedition. Searches resumed and narratives were formed regarding the importance of this expedition for Canadian identity. This article is embedded in a sociocultural perspective and will examine the role that cultural heritage can play in the geopolitics of the Arctic while highlighting the process of ‘patrimonialization’ that the Franklin’s lost expedition has undergone during Harper’s term in office. Based on discourse analysis, it brings out the main narratives that surrounded the modern searches of Franklin’s wrecks which are related to history, national historic sites, mystery, diversity, importance of Inuit knowledge and information gathering. This article demonstrates that these narratives were intended to form a new Canadian northern identity and to assert Canada’s sovereignty over the Arctic.

Consensus Government and Collaboration: The COVID-19 Pandemic in Canada’s North and the Role Partnership Played in Protecting the Health and Well-being of Residents

Despite the varying challenges of the COVID-19 pandemic, the Northwest Territories, a northern Canadian jurisdiction with unique and challenging circumstances from governance style to geography to limited health care capacity, has been one of the leading jurisdictions in Canada to contain the spread of COVID-19.

Measurement of Snow Physical Properties and Stable Isotope Variations in the Canadian Sub-Arctic and Arctic Snowpack

ABSTRACT In northern Canada, the annual peak in river discharge is dominated by the seasonal input of snowmelt. As such, climatic changes that alter snowmelt properties and timing will have cascading impacts on the hydrological system as the Arctic warms. Geochemical tracers provide a tool to characterize the various processes governing the seasonal evolution of the snowpack; however, a lack of snow observations from a variety of Arctic landscapes limits the broad applicability of such tracers and further impedes our understanding of the various processes governing snowpack evolution and its ultimate contribution to the spring discharge peak. This study aims to gain a better understanding of the spatial distribution and the temporal evolution of the natural stable isotope signatures of snow from two distinct ecoregions: open tundra and taiga. More specifically, we describe the geophysical and stable isotope properties of the snow cover at Wekweètì (Northwest Territories), a high sub-Arctic taiga site, and within the Greiner Lake Watershed, near Cambridge Bay (Nunavut), an open Arctic tundra site. Results illustrate a link between snowpack formation and stable isotope distributions at both study sites. Stable oxygen isotope ratios of snow (δ 18O-H2O) show a wide range from −41‰ to −17‰ across all snow depth classes; however, heavy isotope enrichment is clearly visible in the bottom snow layers at both sites. Vapour flux from the ground under a strong temperature gradient is considered to be the main driver for this enrichment due to kinetic metamorphism, which is more prominent at the open tundra site. The stable isotope signatures of the bottom hoar layers during winter were found to be similar to river water values sampled during spring and summer, highlighting the need for more in-depth hydrological cycle assessment.

Thermal-Hydrological-Chemical Modeling of a Covered Waste Rock Pile in a Permafrost Region

In order to reduce contaminant mass loadings, thermal cover systems may be incorporated in the design of waste rock piles located in regions of continuous permafrost. In this study, reactive transport modeling was used to improve the understanding of coupled thermo-hydrological and chemical processes controlling the evolution of a covered waste rock pile located in Northern Canada. Material properties from previous field and laboratory tests were incorporated into the model to constrain the simulations. Good agreement between simulated and observational temperature data indicates that the model is capable of capturing the coupled thermo-hydrological processes occurring within the pile. Simulations were also useful for forecasting the pile’s long-term evolution with an emphasis on water flow and heat transport mechanisms, but also including geochemical weathering processes and sulfate mass loadings as an indicator for the release of contaminated drainage. An uncertainty analysis was carried out to address different scenarios of the cover’s performance as a function of the applied infiltration rate, accounting for the impacts of evaporation, runoff, and snow ablation. The model results indicate that the cover performance is insensitive to the magnitude of recharge rates, except for limited changes of the flow regime in the shallow active layer. The model was expanded by performing an additional sensitivity analysis to assess the role of cover thicknesses. The simulated results reveal that a cover design with an appropriate thickness can effectively minimize mass loadings in drainage by maintaining the active layer completely within the cover.

Young children’s written and verbal responses in a dynamic assessment context

This study reports on dynamic assessment of young children’s emergent writing in northern Canadian classrooms. The one-on-one assessments consisted of open-ended tasks: drawing a picture and then talking and writing about it. Our team analyzed transcripts of 124 adult-child interactions in terms of the assessment administrator’s prompts and the children’s responses to the prompts. We wanted to understand which mediating practices most frequently led to children’s writing performance. Our analysis showed that the three assessment administrators, all of whom had primary teaching experience, most frequently mediated children’s writing by demonstrating how to stretch out the sounds of words that children intended to write. Participating children used print most frequently in response to this form of mediation. Over 90 % of the children wrote either letters or words in the fall administration of the assessment and all children wrote letters or words in the spring administration. Dynamic assessment provided a window into the children’s knowledge about print that would not have been possible had assessment practices not included some form of mediation.

Bioaccumulation of dodecamethylcyclohexasiloxane (D6) in fish

To investigate the bioaccumulation behavior of dodecamethylcyclohexasiloxane (D6, CAS number: 540-97-6) in fish, an OECD-305 style dietary bioaccumulation study of D6 in rainbow trout was conducted in the presence of non-metabolizable reference chemicals. The dietary uptake absorption efficiency of D6 was 14 (3 SE) % and lower than that of the reference chemicals which ranged between 22 (2 SE) to 60 (8 SE) %. The concentration of D6 in the body of the fish showed a rapid 40% drop during the first day of the depuration phase, followed by a slower decline during the remainder of the depuration period. The overall depuration rate constant of D6 was 0.016 (0.0026 SE) d−1 and significantly greater than those of PCB153 and PCB209, which were not significantly different from zero. During the depuration phase, when fish body weight did not significantly change over time, depuration of D6 appears to be almost entirely due to biotransformation in the body of the fish. The biomagnification factor of D6 in rainbow trout was 0.38 (0.14 SE) kg-lipid kg-lipid−1, indicating a lack of biomagnification. The bioconcentration factor (BCF) of D6 in Rainbow trout was estimated at 1909 (483 SE) L kg−1 wet for natural waters of mostly oligotrophic lakes in Northern Canada with an average concentration of total organic carbon of 7.1 mg L−1. Comparing the bioaccumulation profile of D6 to that of 238 similar profiles for 166 unique chemicals indicates that the bioaccumulation capacity of D6 is markedly less than that of many very hydrophobic organochlorines.

Ecology of Arctic rabies: 60 years of disease surveillance in the warming climate of northern Canada.

Rabies occurs throughout the Arctic, representing an ongoing public health concern for residents of northern communities. The Arctic fox (Vulpes lagopus) is the main reservoir of the Arctic rabies virus variant, yet little is known about the epidemiology of Arctic rabies, such as the ecological mechanisms driving where and when epizootics in fox populations occur. In this study, we provide the first portrait of the spatio-temporal spread of rabies across northern Canada. We also explore the impact of seasonal and multiannual dynamics in Arctic fox populations and climatic factors on rabies transmission dynamics. We analysed data on rabies cases collected through passive surveillance systems in the Yukon, Northwest Territories, Nunavut, Nunavik and Labrador from 1953 to 2014. In addition, we analysed a large and unique database of trapped foxes tested for rabies in the Northwest Territories and Nunavut from 1974 to 1984 as part of active surveillance studies. Rabies cases occurred in all Arctic regions of Canada and were relatively synchronous among foxes and dogs (Canis familiaris). This study highlights the spread of Arctic rabies virus variant across northern Canada, with contrasting rabies dynamics between different yet connected areas. Population fluctuations of Arctic fox populations could drive rabies transmission dynamics in a complex way across northern Canada. Furthermore, this study suggests different impacts of climate and sea ice cover on the onset of rabies epizootics in northern Canada. These results lay the groundwork for the development of epidemiological models to better predict the spatio-temporal dynamics of rabies occurrence in both wild and domestic carnivores, leading to better estimates of human exposure and transmission risk.

A hybrid ensemble modelling framework for the prediction of breakup ice jams on Northern Canadian Rivers

The forecasting of river ice jams faces challenges relating to both the availability of data and the complexity of river ice dynamics, resulting in difficulties in model formulation. In this study, a hybrid ensemble modelling framework is developed to address the data scarcity issue and leverage advanced machine learning techniques for the prediction of ice jams with a one-day lead time. The proposed methodology utilises data easily monitored in advance of any ice jam events and maintains a realistic balance between ice jam and non-ice jam events. A combination of both single model algorithms, including classification trees, logistic regression, k-nearest neighbors, support vector machines, and artificial neural networks, and ensemble model algorithms, including random forest, adaptive boosting, gradient boosting, variance penalizing adaptive boosting, logistic boosting, class switching, and adaptive resampling and combining, are considered for both the member models of the first layer of the hybrid ensemble and for the ensemble combiner of the second layer. The final selection of both variables and member models for the hybrid ensemble is detailed, with a focus on the reduction of false negatives, the prediction of no ice jam on a day when one occurs. The proposed method is applied to the St. John River in New Brunswick, Canada, in a location particularly prone to ice jam flooding. Using the proposed methodology, a final model combining 6 different member models using a support vector machine as the ensemble combiner was produced, with a balanced prediction accuracy of 86%. This hybrid ensemble model outperformed the other tested ensemble models, as well as a series of generalized models produced using all available input variables and member models. The model also performed well against other ensemble techniques and against the individual member models. These results demonstrate the viability of the proposed methodology in constructing a hybrid ensemble model for the forecasting of ice jams on Northern Canadian Rivers. The techniques utilised can be adapted to other locations to facilitate ice jam forecasting, requiring data that is easily available and monitored in advance of any potential flooding events.

Assessment of the Amaruq gold deposit signature in glacial sediments using multivariate geochemical data analysis and indicator minerals

The varying nature and thickness of glacial sediments affect the characteristics of mineralized dispersal trains in the Amaruq gold deposit area in Nunavut, northern Canada. To help evaluate the deposit signature, glacial sediments were collected from frost boils along transects parallel to the main ice-flow direction. A complementary detailed geochemical drift exploration dataset and a new Quaternary map were also used to define and interpret the geometry of the mineralized debris dispersal trains. Principal Component Analysis identifies a gold mineralization signature associating As, Ag, Au, Cu, Pb, Sb, W, S, Fe, and Zn and its mafic-BIF (Banded Iron Formation) host rock. This signature, similar to other lode gold geochemical signatures, follows a general NNW dispersal trend, in agreement with the predominant regional and local ice-flow indicators. In a zone characterized by streamlined landforms composed of thick distally -derived till, the dispersal train shows a higher distance for the first indicator to appear at surface down-ice of the known mineralization (~1 km lag) when compared to other mineralized dispersal trains (~300 m lag). Results from this area also show a lower intensity of deposit signature compared to mineralized dispersal trains located in thin locally-derived till characterized by small transverse moraine ridges. Elevated counts of scheelite and pristine-shaped gold grains are found down-ice of mineralization and their distribution is in general agreement with the dispersal train patterns defined by the till-matrix geochemistry. Our results strengthen the use of PCA and indicator minerals combined with an understanding of ice flow dynamics to map deposit signatures at surface and efficiently guide mineral exploration during glacial sediment surveys at local scales.

Assessing the Constraints to the Adoption of Containerized Agriculture in Northern Canada

Considerable advancements are being made in containerized agricultural systems in the northern Canada. These systems are proving successful at overcoming the environmental constraints associated with cold climate food production and hold great promise for remote communities that suffer from high rates of food insecurity. However, if new technologies are to provide lasting and meaningful change for northern communities, critical attention needs to be directed to the variable and complex constraints that may limit their adoption and scalable success. To evaluate the potential uptake and use of containerized agriculture in northern Canada we employed the Adoption and Diffusion Outcome Prediction Tool. Twenty-two variables were ranked according to their influence on adoption. Six variables were then identified as being most constraining to the adoption of containerized agricultural systems, including upfront costs, expected profits, environmental impacts, complexity of the technology, trialability, and reversibility. We believe this type of pre-assessment is a critical, yet often over-looked step in technology transfer, and a necessary stage in assessing the scaling out potential for new food production technologies. This is particularly important for new food production technologies that demand significant financial investments that are wholly or partially irreversible.

Assessing Global Organ Donation Policies: Opt-In vs Opt-Out.

This paper argues that there is little difference between opt-in and opt-out organ donation systems for increasing donor numbers when used in isolation. Independently diverting to an opt-out system confers no obvious advantage and can harm efforts to bolster donations. Rather, it is essential to address barriers to organ donation on several levels along with a switch in system. Moreover, for many countries, it may be more beneficial to adequately capacitate the donation system already in place, rather than entertain a significant change with its attendant resource requirements. For decades, the international transplant community has been involved in vigorous debate as to the merits of moving from default opt-in systems to opt-out policies to grow organ donor numbers and better meet the ever-increasing demand for lifesaving transplants. Opt-out is certainly en vogue, with Wales, England and Nova Scotia recently switching over, Scotland due to become opt-out in March 2021 and Northern Ireland and Canada seriously considering a similar move. Thanks to several countries making the switch from opt-in to opt-out over the last 20–30 years, there are sets of robust longitudinal data that aid in analysing the efficacy of donation systems. However, these data are often contradictory and largely inconclusive, suggesting other factors may be in play. This paper reviews some emerging trends in opt-in versus opt-out organ donation policies and considers recent data that elucidates some of the main contentions across each. Ethical frameworks underpinning donation systems, such as informed consent, trust and transparency, are discussed in detail. Substantial time is also devoted to opt-in vs opt-out systems in developing countries, which tend to be excluded from many analyses, and where the challenges faced are magnified by socio-economic constraints. This constitutes a major gap in recently published literature, as developing countries often lag far behind their developed counterparts in donor and transplant numbers.

Chemical composition and source attribution of sub-micrometre aerosol particles in the summertime Arctic lower troposphere

Abstract. Aerosol particles impact the Arctic climate system both directly and indirectly by modifying cloud properties, yet our understanding of their vertical distribution, chemical composition, mixing state, and sources in the summertime Arctic is incomplete. In situ vertical observations of particle properties in the high Arctic combined with modelling analysis on source attribution are in short supply, particularly during summer. We thus use airborne measurements of aerosol particle composition to demonstrate the strong contrast between particle sources and composition within and above the summertime Arctic boundary layer. In situ measurements from two complementary aerosol mass spectrometers, the Aircraft-based Laser Ablation Aerosol Mass Spectrometer (ALABAMA) and an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), are presented alongside black carbon measurements from an single particle soot photometer (SP2). Particle composition analysis was complemented by trace gas measurements, satellite data, and air mass history modelling to attribute particle properties to particle origin and air mass source regions. Particle composition above the summertime Arctic boundary layer was dominated by chemically aged particles, containing elemental carbon, nitrate, ammonium, sulfate, and organic matter. From our analysis, we conclude that the presence of these particles was driven by transport of aerosol and precursor gases from mid-latitudes to Arctic regions. Specifically, elevated concentrations of nitrate, ammonium, and organic matter coincided with time spent over vegetation fires in northern Canada. In parallel, those particles were largely present in high CO environments (> 90 ppbv). Additionally, we observed that the organic-to-sulfate ratio was enhanced with increasing influence from these fires. Besides vegetation fires, particle sources in mid-latitudes further include anthropogenic emissions in Europe, North America, and East Asia. The presence of particles in the Arctic lower free troposphere, particularly sulfate, correlated with time spent over populated and industrial areas in these regions. Further, the size distribution of free tropospheric particles containing elemental carbon and nitrate was shifted to larger diameters compared to particles present within the boundary layer. Moreover, our analysis suggests that organic matter, when present in the Arctic free troposphere, can partly be identified as low molecular weight dicarboxylic acids (oxalic, malonic, and succinic acid). Particles containing dicarboxylic acids were largely present when the residence time of air masses outside Arctic regions was high. In contrast, particle composition within the marine boundary layer was largely driven by Arctic regional processes. Air mass history modelling demonstrated that alongside primary sea spray particles, marine biogenic sources contributed to secondary aerosol formation via trimethylamine, methanesulfonic acid, sulfate, and other organic species. Our findings improve our knowledge of mid-latitude and Arctic regional sources that influence the vertical distribution of particle chemical composition and mixing state in the Arctic summer.