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Assessments of greenhouse gas (GHG) emissions in managed areas are facing various challenges. A non-flow-through, non-steady-state (NFT-NSS) chamber coupled to a frame permanently inserted into the landfilled substrates is a standard method for quantifying GHG emissions in managed areas, such as pulp and paper mill sludge (PPMS) landfill sites. Frequent measurements are needed to minimize uncertainties on GHG emission factors at the landfill site scale. However, maintaining a frame inserted into the substrates for a long time period is often impossible due to landfilling management operations. Therefore, GHG measurements using NFT-NSS chambers placed directly on substrates' surface could be an interesting option. Our objectives were to determine the relationships between CO 2 , CH 4 , and N 2 O fluxes measured with (F + ) and without (F-) a frame inserted in the substrates' surface and to develop correction factors for fluxes measured without a frame. Measurements were made at different PPMS landfill sites in the province of Québec, Canada. Stronger GHG flux relationships were observed at the provincial (across sites) than the specific site scale: the variance in GHG fluxes from F- chambers explained up to 80 % of variance in fluxes from F + chambers. The measured CO 2 , CH 4 , and N 2 O fluxes in F- chambers were on average 53, 78, and 63 % lower, respectively, than those estimated by the models at provincial scale. The correction factors developed with this approach could greatly extend the number of sites where in situ GHG measurements can be done and would help refining GHG inventories at the provincial and national levels., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Recycling is a commonly acknowledged strategy to reduce the environmental impacts linked to primary resource exploitation. Large regional variations can be observed in recycling processes' parameters, like efficiency, energy mix and treatment of rejects. Life-cycle assessment (LCA) is widely used to evaluate the environmental impacts of recycling processes, but existing studies are neither harmonized nor sufficient to provide a comprehensive geographical and technological coverage of recycling processes. The purpose of this research is to develop an efficient and iterative approach for the parametrized generation of semi-automated regionalized life-cycle inventories that take into account technological and geographical variabilities in the recycling sector. The regionalization framework is then applied to create a parametrized paper recycling regionalization tool. This tool is used in the results section to compare the national climate change impacts of recycling three paper grades. Results show a significant global warming impact variability between countries for recycled graphic paper (0.36 to 2.25 kg CO 2 -Eq/kg wastepaper recycled), newsprint (0.27 to 1.84 kg CO 2 -Eq/kg wastepaper recycled) and corrugated cardboard (0.28 to 1.68 kg CO 2 -Eq/kg wastepaper recycled) productions. A regionalized LCA of the international recycling of the mixed wastepaper exported from Quebec's (Canada) sorting centers is also performed with the tool and compared to the non-regionalized mixed wastepaper recycling process available in the ecoinvent database. Only nine midpoint ReCiPe impact categories remain environmentally advantageous compared to virgin paper production when applying the regionalization methodology, compared to sixteen when using the ecoinvent process, illustrating how regionalization can substantially influence LCA results., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Applying a mixed frequency vector autoregressive (MF-VAR) approach, we examine relationships between CO 2 emissions and economic growth from 1970Q1 to 2019Q4 among G7 countries. We incorporate primary energy consumption as a control variable, to avoid any bias from an omitted variable. Our empirical results, using forecast error variance decomposition and a Granger causality check, suggest that MF-VAR exhibits better explanatory ability over the more commonly used VAR model employing single frequency data. Results from LF-VAR exhibit a feedback loop connecting economic expansion and emissions of CO 2 with one-way Granger causality from primary energy consumption to growth of the economies studied. MF-VAR model results also indicate that, in G7 countries, economic expansion exhibits a one-way causal link to CO 2 emissions in Canada, UK, and US cases. Interestingly, MF-VAR shows feedback between economic expansion and primary energy use in Germany, while LF-VAR quantifies the link from economic growth to CO 2 emissions in Canada and from CO 2 to economic growth in the UK. Results raise implications for the G7 samples' policymakers., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The ecological footprint has currently become a highly popular environmental performance indicator. It provides the basis for setting goals, identifying options for action, and tracking progress toward stated goals. Because the examination of the existence of convergence is important for the climate change protection of the earth, the convergence of ecological footprint and its subcomponents are a major concern for scholars and policymakers. To this end, this study aims to investigate the stochastic convergence of ecological footprint and its subcomponents. We employ the recently developed Hepsag (2021) unit root test that allows nonlinearity and smooth structural change simultaneously to study stochastic convergence in per-capita ecological footprint over the period 1961-2018 for the most polluting countries. The results provide mixed evidence of the presence of stochastic convergence in conventional unit root tests such as ADF, KPSS and Fourier KPSS. According to the Hepsag (2021) unit root test results for all countries, built-up land footprint converges except Australia, Malaysia, Poland, and Turkey. Carbon footprint converges for Indonesia, Malaysia, Mexico, South Africa, Thailand, Turkey, the UK, and the USA. Cropland footprint converges for Australia, Canada, China, France, Indonesia, Italy, Japan, Korea, Malaysia, Mexico, Poland, South Africa, the UK, and Vietnam. Fishing grounds footprint converges in Brazil, France, Germany, Indonesia, Italy, Mexico, South Africa, and Vietnam. Forest product footprint converges in Australia, Canada, France, Germany, India, Korea, Mexico, Poland, Turkey, and Vietnam. Grazing land footprint converges in Canada, France, India, Indonesia, Japan, Korea, Poland, South Africa, Thailand, and Vietnam. And lastly, the total ecological footprint converges in Canada, France, Korea, Malaysia, Mexico, South Africa, the UK, and the USA., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Energy is unquestionably necessary for economic progress; nevertheless, it also produces CO 2 emissions, which are the primary cause of climate change and environmental degradation. Renewable energy, which consists of non-carbohydrate energy sources that do not or seldom emit emissions, can assist the accomplishment of both ecological sustainability and sustainable development in this respect. Against this background, this paper takes into account political risk and assesses the impact of renewable energy use on CO 2 emissions in Canada from 1990 to 2018 controlling economic growth and trade globalization. The present research utilized an innovative dynamic ARDL method that overcomes the limitations of the ARDL method. The results revealed significant evidence of cointegration. In the long run, we established that a surge in economic growth, political risk, renewable energy use, and trade globalization mitigates environmental degradation. Furthermore, the outcomes of the frequency domain causality disclosed that in the long term, economic growth, political risk, renewable energy use, and trade globalization can predict CO 2 emissions in Canada. Since the political stability in Canada has helped to attract foreign firms to invest. Therefore, ensuring political stability will bring in more foreign investment, forcing the Canadian government to take its climate crisis problem more seriously., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Carbon dioxide removal (CDR) technologies, such as direct air carbon capture and storage (DACCS), will be critical in limiting the rise of the average global temperature over the next century. Scaling up DACCS technologies requires the support of a complex array of policies and infrastructure across multiple overlapping policy areas, such as climate, energy, technology innovation and resource management. While the literature on DACCS and other CDR technologies acknowledges the path-dependent nature of policy development, it has tended to focus on abstract policy prescriptions that are not rooted in the specific political, social and physical (infrastructural) context of the implementing state. To address this gap, this paper provides a country-level study of the emerging DACCS policy regime in Canada. Drawing on the existing literature that identifies idealized (acontextual) policy objectives that support DACCS development and effective regulation, we identify the actionable policy objectives across six issue domains: general climate mitigation strategies; energy and resource constraints; carbon storage and transport regulation and infrastructure; financing scale-up and supporting innovation; removal and capture technology availability and regulation; and addressing social acceptability and public interest. Using a database of Canadian climate policies (n = 457), we identify policies within the Canadian (federal and provincial) policy environment that map to the idealized policy objectives within each of these domains. This exercise allows us to analyze how key policy objectives for DACCS development are represented within the Canadian system, and enables us to identify potential niches, and landscape influences within the system, as well as gaps and potential barriers to the system transition process. This paper contributes to our understanding of national DACCS policy development by providing a framework for identifying components of the DAC system and linking those components to desired policy outcomes and may provide a basis for future cross-country comparisons of national-level DACCS policy. [ABSTRACT FROM AUTHOR]

Over the past two decades, numerous developed and developing nations have witnessed a remarkable shift from manufacturing-based economies to those that center around the service sector. This development has led to a staggering growth in the consumption of energy-intensive goods, and Canada has not been immune to this trend. Despite being home to abundant energy reserves, the country's economic expansion has manifestly relied on prodigious energy consumption. Within this context of symbiotic energy-economic growth, this study investigates the empirical relationship between energy consumption and economic growth using Canadian time-series data from 1980 to 2020. In doing so, this paper offers a vital contribution to the development of theoretical frameworks within the sphere of endogenous growth. Besides, to arrive at empirical findings, a model known as the autoregressive distributed lag (ARDL) model, renowned for its ability to discern both short- and long-term coefficients, is employed. The results reveal that economic growth has a significant positive long-run effect on energy consumption and other explanatory variables. All variables other than trade openness demonstrate a positive relationship with economic growth in the short run. From Toda-Yamamoto causality test, it is evident that there exist bidirectional causal links between economic growth and energy consumption and between economic growth and financial development. Several unidirectional causalities were also observed for other variables. Based on these findings, it is recommended that Canada boosts its investment in energy infrastructure, especially in rural and backward regions, to deliver necessary energy services. An optimal trade-off between Canada's vast energy resources and economic growth can perhaps be achieved by minimizing the disparity in access to energy services across all parts of the country. Other policy implications are discussed., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This paper aims to capture the effect of environmentally related taxes on environmental quality in Canada while controlling economic growth, financial development, and energy consumption over the period of 1990Q1 to 2020Q4. The present study employs novel econometric approaches, namely, the nonlinear autoregressive distributed lag (N-ARDL) test and the gradual shift causality (GS-C) test. The outcomes of the study reveal that (i) there is long-run cointegration equation between environmental taxes (E-TAX), carbon dioxide emissions (CO 2 E), economic growth (ECG), financial development (FD), and primary energy consumption (PREC); (ii) E-TAX causes to decrease in environmental degradation in Canada; (iii) PREC and ECG increase (and cause) environmental degradation in Canada; and (iv) financial development also positively affect the environmental sustainability. This effort may also be of great importance for policymakers and decision-makers to better understand the factors of environmental degradation for developing effective tax policies that will alleviate human impacts and contribute to reducing environmental degradation., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Across Canada's boreal forest, disturbances from in situ oil sands mining, including well‐pads, significantly impact vast areas of the landscape. The creation of well‐pads requires removal of vegetation and placement of mineral fill, which essentially stops any carbon (C) sequestration on the once peatland ecosystem. It is important that, once no longer in use, these well‐pads are restored as long‐term C (peat) accumulation is what defines peatland ecosystem. However, little is known about the recovery of greenhouse gas exchange post‐restoration of these features. We studied a decommissioned well‐pad located in a treed poor fen that was restored using three soil adjustment treatments (SATs): (1) complete mineral fill removal (Peat‐Dec); (2) partial pad removal and burial under peat layer (BUPL); and (3) mixing mineral and peat by inversion (Mixed‐P‐M). The recreated peat surface was revegetated with donor peatland species using the moss layer transfer technique (MLTT). The objectives of this paper were to (1) quantify plot‐scale seasonal carbon dioxide (CO2) and methane (CH4) exchange of the SATs, 2–4 years post‐restoration compared to reference sites and (2) determine the influence of several environmental variables on CO2 and CH4 exchange. All SATs proved effective in recreating a soil surface needed to support peatland vegetation as shown by similar rates of net ecosystem exchange (NEE). Equally, both types of vegetation reintroduced led this site on a trajectory toward functioning as a net C sink. [ABSTRACT FROM AUTHOR]

In recent times, there has been increase in climate change protest across the globe. However, whether decrease in emissions is connected with climate change protest or not is yet to be documented in the literature. Consequently, the aim of this study is to fill this gap by examining ex-post detection of how climate change protests and its interconnectedness with CO2 emissions. Using the Bai and Perron (1998) structural break test, we estimate the number of breaks as well as the date of such structural breaks in CO2 emissions series for 41 countries. Our aim is to match the date of the climate change protests to those of the structural breaks. We observe that climate change protests are fairly consistent with the dates of breaks in Europe and Asia, but not in BRICS economies or US, Canada and other countries. Therefore, this method allows us to solve a gap in the energy industry related to the modelling and correct allocation of positive shocks in CO2 emissions to climate change protests., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This paper empirically investigates the effect of carbon emissions on sovereign risk? To answer this question, we use fixed effects model by using annual data from G7 advanced economies, which includes Canada, France, Germany, Italy, Japan, UK and USA, for the period from 1996 to 2014. We employ a novel extreme value theory to measure sovereign risk. The results indicate that climate change (carbon emissions) are likely to increase sovereign risk significantly. We also expand our analysis to some specific sectors, as some of the sectors emit more carbon than others. Specifically, we take top three polluting sectors namely: transportation, electricity and industry and show that they are more likely to increase the sovereign risk. Our results are robust to change in risk measures, estimation in differences and dynamic version of econometric models. Therefore, we have robust consideration that the carbon emissions significantly explain the sovereign risk., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This paper contributes to the growing literature regarding the role of Information and Communication Technologies as well as Innovation on driving the level of carbon dioxide emissions and economic growth in context of the 21st conference of the Parties to the Climate convention (COP21). Drawing the data from 13 selected G-20 countries (including Argentina, Canada, China, France, Germany, Italy, Japan, Mexico, Republic of Korea, Russian Federation, Turkey, United Kingdom, United States) during the period of 15 years, our study achieves significant results. First, only five factors impede the carbon emissions namely energy price, foreign direct investment, technology, spending on innovation and trade openness while the remainder of determinants contribute to contamination of environment, including financial development. Second, when it comes to economic growth, information and communication technological and financial development are positive driving factors. Our results do reject the absence of Environmental Kuznets Curve (EKC) from our sample. Finally, our study empirically suggests that the work of controlling consumption of oil and environmentally friendly process including manufacture-trading in these economies will limit the amount of pollution., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This paper investigates the relationships among the important process parameters that impact Post-combustion Carbon Capture (PCC) carbon dioxide (C O 2) separation. A better understanding of the complex relationships among those parameters can support optimization and performance enhancement of the separation process. Being able to precisely predict the process parameters will enable the operator to determine the current state of the process, forecast any potential changes or events, and adjust process parameters to enhance the plant's performance. With the objective of studying the process parameters' correlations in the amine-based PCC process, we modeled the multi-year historical production data of the Clean Energy Technologies Research Institute (CETRi) (formerly known as the International Test Center for PCC or ITC) in Regina, Saskatchewan, Canada, using a Decision Forest approach. The model validation process revealed that the Decision Forest model produced higher predictive accuracy than previous efforts. The Decision Forest models we developed also represent knowledge about the importance of parameters involved in the capture process, and such knowledge is useful for further optimization of the capture process in the future. • Modeling the parameters of the Carbon Capture process with machine learning (ML). • The ML models used Decision Forest with Gradient Boosting and Oblique Split. • The ML models achieved superior predictive accuracy compared to past efforts. • The ML models support interpretability by visualizing weights and prediction paths. [ABSTRACT FROM AUTHOR]

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• New carbon-sequestration geosystem paradigm proposed for screening CO 2 repositories. • Deposition, burial history 1st-order controls on repository attributes, traps, etc. • Genetic understanding of geology enables property prediction away from data control. • Case-study application to heavily industrialized region of onshore Canada. In this paper, I propose a new geoscience paradigm for evaluating potential carbon-sequestration targets. I introduce the term carbon-sequestration geosystem to study and describe portions of sedimentary basins where all the geologic components necessary for the safe and long-term storage of CO 2 are present. The purpose of this type of analysis, most appropriately applied at a basin-screening stage, is to derive a holistic, genetic, and predictive understanding of the geology – the depositional systems, structural setting and other factors that are direct controls on storage, injectivity, potential for induced seismicity, and other critical factors. To illustrate the concepts, I present a re-evaluation of the geologic carbon-sequestration options in Southern Ontario (Canada) where business and environmental needs, mostly associated with hard-to-abate industries, require urgent action. Legacy wireline-logs, core, and outcrop data are the main data sources available in this onshore setting. The results of this new, independent study are broadly similar to those of previous studies: the Cambrian section, a saline aquifer, is the most likely candidate to be a CO 2 repository. However, the methodology used identified several issues (e.g., stratigraphic heterogeneity, proximity to basement) that will need addressing by targeted data collection and/or analysis before site-selection for a test should be undertaken. [ABSTRACT FROM AUTHOR]

Many firms generate large amounts of carbon dioxide and other greenhouse gases when they burn fossil fuels in their production processes. In addition, production of raw materials and other inputs the firms procure for their operations also generates greenhouse gases indirectly. These direct and indirect greenhouse gas emissions occur in many sectors of our economies. In this paper, we first present sector-specific estimates for such greenhouse gas emissions. We then show that estimates for such sector-specific greenhouse gas emissions are often required for various types of corporate as well as public policy analyses in both domestic and international contexts. Measuring greenhouse gas emissions resulting from firms' multi-stage production processes in a multi-sector context is relevant for policies related to the Kyoto protocol, an international agreement to limit global greenhouse gas emissions. For example, since the protocol allows firms to engage in trading and offsetting of their greenhouse gas emissions across national borders, provided that emissions are correctly measured, the firms can take advantage of such trading schemes by placing their energy-intensive production facilities globally and strategically. We present several case studies which illustrate the importance of this and other aspects of greenhouse gas emissions in firms' environmental management. We also argue that our modeling and estimation methods based on input-output analyses are suitable for the types of research goals we have in this paper. Our methods are applied to data for Canada and Japan in a variety of environmental management circumstances.

In the pursuit of mitigating the performance gap between model-predicted thermal comfort and measurements of perceived thermal comfort, recent studies have investigated the multi-domain nature of thermal comfort and IEQ. This paper presents an update to a recent work that applied Bayesian logistic regression to examine possible independent correlations between perceived thermal comfort of building occupants and metrics of indoor environmental quality (IEQ) such as CO 2 concentrations. The prior work made use of the COPE dataset, a 20-year-old field database of objective and subjective IEQ measurements collected from approximately 800 occupants of open-plan offices in large Canadian and US cities. This study updates that work with a new IEQ field study of 141 workstations carried out at the University of British Columbia across 2019 and 2020. In addition, a new, hierarchical (multi-level) Bayesian logistic regression model is formulated and applied. The new results not only increase the credibility of observing measurements of CO 2 concentrations to improve predictions of thermal satisfaction in the original COPE dataset, but that the credibility of this evidence is strengthened on the addition of the new data. At indoor temperatures of 23.5 °C, the probability of an occupant feeling thermally satisfied at measured CO 2 levels of 550 ppm was 0.62 [0.54 - 0.69, 95% CrI]. This decreased to 0.28 [0.17-0.42, 95% CrI] at 750 ppm. This study does not suggest these observations are generalizable outside the COPE and UBC datasets, nor does it suggest that CO 2 must be affecting occupants physiologically or psychologically to cause these observations. However, it is suggested that CO 2 levels may remain overlooked as a contextual, or latent variable for the real-time prediction of perceived thermal comfort in buildings. For instance, prior research has observed a relationship between indoor CO 2 levels and perceived air quality as well as a relationship between multiple perceptual factors of IEQ, such as air quality and thermal comfort. If the findings of this paper continue to be found in future studies, measurements of CO 2 concentrations may be used to improve the accuracy of thermal comfort prediction models. The core recommendation for future work is therefore to expand measurements in future thermal comfort field studies to include, at least, measurements of indoor CO 2 levels. A greater dataset is needed to determine whether the findings of this study are possibly universally applicable, and/or whether knowledge of indoor CO 2 concentrations may improve personalized models of thermal comfort that are building- and context-specific. • A new IEQ field study of office workers in Canada adds 141 samples to a prior dataset. • The newly collected IEQ database is publicly accessible as part of this publication. • The data is applied to a new hierarchical Bayesian logistic regression model. • Indoor CO 2 levels are found to credibly improve predictions of thermal satisfaction. • Increases in CO 2 levels correlate to observed decreases in thermal satisfaction. [ABSTRACT FROM AUTHOR]

In spring 2002, an atmospheric measurement site was established at the peak of Whistler Mountain in British Columbia, Canada to measure trace gases, particle chemistry and physics, and meteorology. This paper uses continuous measurements from March 2002 to December 2006 to investigate the influence of trans-Pacific transport and North American forest fires on both O3 and CO at Whistler. Annual mean mixing ratios of O3 and CO were 41 ppbv (monthly means of 35-48 ppbv) and 145 ppbv (monthly means of 113-177 ppbv) respectively with both species exhibiting an annual cycle of late-winter to early-spring maxima and summer minima. The absence of a broad summer O3 peak differs from previously-reported high altitude sites in the western US. The highest monthly-averaged O3 and CO mixing ratios relative to the 5-yr monthly means were seen in fall 2002 and spring 2003 with increased O3 and CO of 10% and 25% respectively. These increases correspond to anomalously-high values reported at other Northern Hemisphere sites and are attributed to fires in the Russian Federation. Air mass back trajectory analysis is used to associate the mean enhancements of O3 and CO with trans-Pacific transported or North American air masses relative to the Pacific background. Mean values of the enhancements for March to June in trans-Pacific air masses were 6 ppbv and 16 ppbv for O3 and CO respectively. In summers 2002-2006, higher CO and O3 mixing ratios were almost always observed in North American air masses and this relative enhancement co-varied for each year with the western US and Canada total wild- fire area. The greatest enhancements in O3 and CO were seen in 2004, a record year for forest fires in Alaska and the Yukon Territory with average O3 and CO mixing ratios 13 and 43 ppbv above background values. [ABSTRACT FROM AUTHOR]

The 'Modified Sturm Test' uses carbon dioxide production as the primary end point in assessing the biodegradation potential of organic chemicals. This test was conducted by a commercial laboratory to assess the potential biodegradability of an oil stabilizer sample from an oil company in Canada. There was a high percentage conversion of total organic carbon present in the sample but carbon dioxide measured was low. Many possibilities were analyzed in this paper in order to understand the situation. The analysis showed that the test was subject to criticism from the point of view of CO2 measurement, 10-day window period, and aeration/mixing conditions.

The Canadian Middle Atmosphere Model (CMAM) has been used to examine the middle atmosphere response to CO2 doubling. The radiative-photochemical response induced by doubling CO2 alone and the response produced by changes in prescribed SSTs are found to be approximately additive, with the former effect dominating throughout the middle atmosphere. The paper discusses the overall response, with emphasis on the effects of SST changes, which allow a tropospheric response to the CO2 forcing. The overall response is a cooling of the middle atmosphere accompanied by significant increases in the ozone and water vapor abundances. The ozone radiative feedback occurs through both an increase in solar heating and a decrease in infrared cooling, with the latter accounting for up to 15% of the total effect. Changes in global mean water vapor cooling are negligible above ∼30 hPa. Near the polar summer mesopause, the temperature response is weak and not statistically significant. The main effects of SST changes are a warmer troposphere, a warmer and higher tropopause, cell-like structures of heating and cooling at low and middlelatitudes in the middle atmosphere, warming in the summer mesosphere, water vapor increase throughout the domain, and O3 decrease in the lower tropical stratosphere. No noticeable change in upward-propagating planetary wave activity in the extratropical winter–spring stratosphere and no significant temperature response in the polar winter–spring stratosphere have been detected. Increased upwelling in the tropical stratosphere has been found to be linked to changed wave driving at low latitudes. [ABSTRACT FROM AUTHOR]

The Neoproterozoic St Honoré carbonatite complex is one of three currently mined niobium deposits. In these and most other carbonatite-hosted niobium deposits, pyrochlore is the principal ore mineral. Four major pyrochlore-bearing rock types are observed in the St Honoré complex, namely, biotitite, magnetite-biotite rock, apatitite and carbonatite. The textural relationships among the different rock types and within each rock type are extremely complex, as are the textures and crystal chemistry of the pyrochlore. Compositionally, there are two major types of pyrochlore. Type-1 is enriched in Ta, U, Zr, Sr, Th, Fe, REE and Cl and Type-2 is a Ca-Na-F-rich pyrochlore, with proportions of other elements close to or below their detection limits. Type-1 pyrochlore is yellow- to red-brown and, in many cases, displays oscillatory zoning. This variety occurs most commonly in the cores of crystals in apatitite, where it has its highest concentrations of the elements listed above. It also is observed in biotitite, but the proportions of the above elements are much lower. Type-2 pyrochlore is light to dark brown and, generally, does not exhibit oscillatory zoning. It forms overgrowths on Type-1 pyrochlore in apatitite and biotitite, and occurs as large crystals in the magnetite-biotite rock (Type-1 pyrochlore is not present in this rock). We propose that Type-1 pyrochlore crystallised from a highly evolved, fluid-undersaturated carbonatitic magma, whereas Type-2 pyrochlore crystallised from a carbonatitic magma that had undergone fluid exsolution, which depleted the magma in elements that tend to partition preferentially into aqueous fluids, i.e., U, Sr, Fe, REE, Ba and Cl. The processes that governed the evolution of the carbonatitic magma (which was mantle-derived and introduced in numerous small batches) and crystallisation of pyrochlore at St Honoré were biotitisation (by the magma), crystallisation of calcite and aqueous fluid exsolution. Biotitisation of the host syenite consumed MgO, H 2 O and CO 2 from each magma batch (the CO 2 was released as a gas), leading to the crystallisation of Type-1 pyrochlore in biotitite. This process also locally increased the CaO content of the magma to a level sufficient to saturate it with calcite, leaving a residual phoscoritic magma that crystallised the most Ta-U-enriched variety of Type-1 pyrochlore. Exsolution of the aqueous fluid occurred as a result of prolonged crystallisation and/or pressure release and led to the crystallisation of Type-2 pyrochlore. The evolution of each of the magma batches was different and depended on the extent of biotitisation, on whether calcite crystallised, and on the timing of fluid exsolution. As the two types of pyrochlore and their temporal relationship have been described for many carbonatite complexes, the hypotheses presented in this paper are likely also applicable to the genesis of pyrochlore in these other complexes. [ABSTRACT FROM AUTHOR]

Abstract This paper presents an empirical model of net ecosystem CO2 exchange (NEE) developed for a subarctic fen near Churchill, Manitoba. The model with observed data helps explain the interannual variability in growing season NEE. Five years of tower-flux data are used to test and examine the seasonal behaviour of the model simulations. Processes controlling the observed interannual variability of CO2 exchange at the fen are examined by exploring the sensitivity of the model to changes in air temperature, precipitation and leaf area index. Results indicate that the sensitivity of NEE to changing environmental controls is complex and varies interannually depending on the initial conditions of the wetland. Changes in air temperature and the timing of precipitation events have a strong influence on NEE, which is largely manifest in gross ecosystem photosynthesis (GEP). Climate change scenarios indicate that warmer air temperatures will increase carbon acquisition during wet years but may act to reduce wetland carbon storage in years that experience a large water deficit early in the growing season. Model simulations for this subarctic sedge fen indicate that carbon acquisition is greatest during wet and warm conditions. This suggests therefore that carbon accumulation was greatest at this subarctic fen during its early developmental stages when hydroclimatic conditions were relatively wet and warm at approximately 2500 years before present. [ABSTRACT FROM AUTHOR]

Introduction: Medical air (MA) is widely used in hospitals, often manufactured onsite by compressing external ambient air and supplied through a local network piping system. Onsite production gives rise to a risk of impurities that are governed by the same pharmacopoeia purity standards applicable to commercially produced MA. The question to be addressed in this paper is how to assess if a lack of purity poses a medical problem? Methods: The MA produced onsite at a major Canadian hospital was monitored for carbon dioxide (CO2) and other impurity gases at high frequency (one per minute) over a two-month period. Results: The average CO2 concentration was 255 ppm. The United States Pharmacopeia (USP) threshold of 500 ppm was exceeded during 1% of the total study period, and the average while exceeding the threshold was 526 ppm. The maximum concentration was 634 ppm. Discussion and conclusion: To our knowledge, there is only one study that evaluated the effects suffered by respiratory patients of elevated nitric oxide in MA; thus, it is not clear what are the medical bases for the thresholds stated in the USP. To perform a Quality Risk Assessment, the threshold and the time above threshold should be considered in determining the frequency of sampling and analysis, and operating methods required to ensure the quality of MA entering the pipeline meets the clinical, regulatory, and patient safety standards. In conclusion, because the USP does not provide impurity thresholds for specific patients nor time above thresholds, there is a need for the medical community to determine these quantities before it can be known if the purity of MA is a problem. [ABSTRACT FROM AUTHOR]

Improving the environmental performance of built environments has received wider interest in the recent past. Asset management is an under-utilized strategy to enhance and maintain desired environmental performance of a building at low life cycle costs (LCC). Current asset management decision-making methods are not fully capable of incorporating future technological changes and complex time sensitive environmental demands. There is a knowledge gap in incorporating factors such as environmental performance, risk and time sensitivity to foster dynamic asset management decision making. This paper presents a multi-period asset management method for public buildings to minimize LCC and attain climate action goals. A scenario planning approach is used to incorporate future changes in technologies, costs and organizational policies. Risk based prioritization is used to compare and select maintenance alternatives in a given period. Value at risk is used to identify the lowest risk capital planning strategy for an organization. The proposed approach was demonstrated using an operating aquatic centre building in British Columbia, Canada. Three possible future scenario were considered. Proposed method was used to develop multi-period maintenance plans for future scenarios. Based on the analysis, Great Transitions scenario is expected to achieve the least financial risk. The proposed approach enable capital asset planning by complying with changing climate action targets in a stochastic environment. [ABSTRACT FROM AUTHOR]

Inland waters are hotspots of greenhouse gas (GHG) cycling, with small water bodies particularly active in the production and consumption of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). However, wetland ponds are being replaced rapidly by small constructed reservoirs in agricultural regions, yet it is unclear whether these two water body types exhibit similar physical, chemical, and environmental controls of GHG content and fluxes. Here, we compared the content and regulatory mechanisms of all three major GHGs in 20 pairs of natural wetland ponds and constructed reservoirs in Canada's largest agricultural region. Carbon dioxide content was associated primarily with metabolic indicators in both water body types; however, primary production was paramount in reservoirs, and heterotrophic metabolism a stronger correlate in wetland ponds. Methane concentrations were correlated positively with eutrophication of the reservoirs alone, while competitive inhibition by sulfur‐reducing bacteria may have limited CH4 in both waterbody types. Contrary to expectations, N2O was undersaturated in both water body types, with wetlands being a significantly stronger and more widespread N2O sink. Varying regulatory processes are attributed to differences in age, depth, morphology, and water‐column circulation between water body types. These results suggest that natural and constructed water bodies should be modeled separately in regional GHG budgets. Plain Language Summary: Small inland water bodies, ponds and reservoirs, are hotspots of greenhouse gas (GHG) production. However, modern farming practices replace natural wetlands by artificial reservoirs, without consideration on the effects on landscape GHG fluxes. Here we measured concentrations and controls of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in locally‐paired wetland ponds and agricultural reservoirs and found that while GHG concentrations were similar in the two waterbody types, underlying mechanisms differed, owing to the differences in shape, depth, and age of individual water bodies. Shallower wetland ponds were typically more fully mixed, exhibited more oxygen at depth, and had higher nutrients and organic carbon concentrations reflecting their ages. Findings suggest that the balance between wetland drainage and reservoir construction may have a pronounced effect on regional budgets of GHG fluxes, particularly in the face of forthcoming climate changes. Key Points: CO2 content was associated with metabolism; primary production in reservoirs, but bacterial respiration in wetlandsCH4 concentrations were correlated positively with either eutrophication (reservoirs) or competitive inhibition of methanogenesis (both)N2O undersaturation was ubiquitous, but wetlands were stronger and more widespread N2O sinks [ABSTRACT FROM AUTHOR]

[Display omitted] • Post-plasma constriction of a CO 2 microwave plasma enhances conversion and energy efficiency. • Increased performance is the result of enhanced molecular transport from the plasma region. • 3D CFD simulations showed that the constriction encourages product retention, which results in increased performance. Transforming CO 2 into value-added chemicals is crucial to realizing a carbon–neutral economy, and plasma-based conversion, a Power-2-X technology, offers a promising route to realizing an efficient and scalable process. This paper investigates the effects of post-plasma placement of a converging–diverging nozzle in a vortex-stabilized 2.45 GHz CO 2 microwave plasma reactor to increase energy efficiency and conversion. The CDN leads to a 21 % relative increase in energy efficiency (31 %) and CO 2 conversion (13 %) at high flow rates and near-atmospheric conditions. The most significant performance improvement was seen at low flow rates and sub-atmospheric pressure (300 mbar), where energy efficiency was 23 % and conversion was 28 %, a 71 % relative increase over conditions without the CDN. Using CFD simulations, we found that the CDN produces a change in the flow geometry, leading to a confined temperature profile at the height of the plasma, and forced extraction of CO to the post-CDN region. [ABSTRACT FROM AUTHOR]

Empirical studies of the EKC hypothesis may be very sensitive to datasets, specifications, and functional forms. The aim of this paper is to investigate the long-run relationship among CO 2 emissions, real GDP, and energy consumption using a panel of 9 advanced economies from 1870 to 2008 using both parametric and semi-parametric additive models. While at the panel level the results provide support to the Environmental Kuznets Curve (EKC) only in the post-1950s period, at the individual country level the inverted U-shaped relationship between CO 2 and real GDP is validated for a subset of countries only. However, when a semi-parametric regression framework is applied an inverse U-shaped pattern becomes clear for all countries of the sample, except Canada. Empirical findings indicate that relaxing the restrictions associated with parametric regression models may be critical for the question of investigating the existence of the EKC. • Panel data results provide support to the EKC only in the post-1950s period. • Semi-parametric regressions reveal an inverse U-shaped pattern for all countries, except Canada • An effective policy to reduce CO 2 emissions should encourage innovation activities in low-emission technologies. [ABSTRACT FROM AUTHOR]

We assess the extent to which subsidies for home energy efficiency improvements in Canada have been paid to households that would have undertaken the improvements anyway--the so-called free rider rate. We focus on forced-air natural gas furnaces, replaced between April 1, 2007 and March 31, 2011, under both federal and provincial subsidy programs as well as the 2009 federal Home Renovation Tax Credit. Our results indicate that around 50 percent of expenditures under the Canadian subsidy and tax credit programs represented free riding. In the long run, our estimates suggest that over 80 percent of grant recipients would have chosen an identical furnace at the time of replacement. We estimate that the cost effectiveness of the programs in terms of greenhouse gas reduced was between $70 and $110/t CO2, depending on the assumptions made. Further, we find that a substantial majority of the grants were received by middle- and high-income households, such that the grant had a regressive effect on the distribution of income. We conclude that such grants are not an optimal way to improve residential energy efficiency. [ABSTRACT FROM AUTHOR]

The carbon (C) dynamics of northern peatlands are sensitive to hydrological changes owing to ecohydrological feedbacks. We quantified and evaluated the impact of water level variations in a beaver pond (BP) on the CO2 flux dynamics of an adjacent, raised Sphagnum–shrub-dominated bog in southern Canada. We applied the CoupModel to the Mer Bleue bog, where the hydrological, energy and CO2 fluxes have been measured continuously for over 20 years. The lateral flow of water from the bog to the BP was estimated by the hydraulic gradient between the peatland and the BP's water level and the vertical profile of peat hydraulic conductivity. The model outputs were compared with the measured hydrological components, CO2 flux and energy flux data (1998–2019). CoupModel was able to reproduce the measured data well. The simulation shows that variation in the BP water level (naturally occurring or due to management) influenced the bog net ecosystem exchange (NEE) of CO2. Over 1998–2004, the BP water level was 0.75 to 1.0 m lower than during 2017–2019. Simulated net CO2 uptake was 55 gCm-2yr-1 lower during 1998–2004 compared to 2017–2019 when there was no BP disturbance, which was similar to the differences in measured NEE between those periods. Peatland annual NEE was well correlated with water table depth (WTD) within the bog, and NEE also shows a linear relation with the water level at the BP, with a slope of - 120 gCO2-Cm-2yr-1m-1. The current modelling predicts that the bog may switch from CO2 sink to source when the BP water levels drop lower than ∼ 1.7 m below the peat surface at the eddy covariance (EC) tower, located on the bog surface 250 m from the BP. This study highlights the importance of natural and human disturbances to adjacent water bodies in regulating the net CO2 uptake function of northern peatlands. [ABSTRACT FROM AUTHOR]

Accurate visualization of air temperature distribution can be useful for various thermal analyses in fields such as human health and heat transfer of local area. This paper presents a novel approach to measuring air temperature from midwave hyperspectral Fourier transform infrared (FTIR) imaging in the carbon dioxide absorption band (between 4.25–4.35 μ m). In this study, the proposed visual air temperature (VisualAT) measurement is based on the observation that the carbon dioxide band shows zero transmissivity at short distances. Based on analysis of the radiative transfer equation in this band, only the path radiance by air temperature survives. Brightness temperature of the received radiance can provide the raw air temperature and spectral average, followed by a spatial median-mean filter that can produce final air temperature images. Experiment results tested on a database obtained by a midwave extended FTIR system (Telops, Quebec City, QC, Canada) from February to July 2018 show a mean absolute error of 1.25 ∘ K for temperature range of 2.6−26.4 ∘ C. [ABSTRACT FROM AUTHOR]

Biomass burning is an important and changing component of global and hemispheric carbon cycles. Boreal forest fires in Russia and Canada are significant sources of the greenhouse gases carbon dioxide (CO2) and methane (CH4). The influence of carbon monoxide (CO) on the greenhouse effect is practically absent; its main absorption bands of 4.6 and 2.3 μm are far away from the climatically important spectral regions. Meanwhile, CO concentrations in fire plumes are closely related to CO2 and CH4 emissions from fires. On the other hand, satellite measurements of CO are much simpler than those of the aforementioned gases. The Atmospheric Infrared Sounder (AIRS) operating in the Thermal IR spectral region has provided a satellite-based CO data set since October 2002. This satellite data allow to estimate CO emissions from biomass burning north of 30° N using a simple two-box mass-balance model. These results correlate closely with independently estimated CO emissions from the GFED4c bottom-up database. In 2021, both estimate record high emissions throughout the preceding two decades, double the annual emissions compared to previous periods. There have been two years with extremely high emissions (2003 and 2021) but for the rest of the data, an upward trend with a rate of 3.6 ± 2.2 Tg CO yr−2 (4.8 ± 2.7% yr−1) was found. A similar rate of CO emissions can be seen in the GFED4c data. [ABSTRACT FROM AUTHOR]

We report the first water‐column dissolved methane data set from the Estuary and Gulf of St. Lawrence (EGSL). Per surface‐water methane concentration and sea‐to‐air flux, the upper estuary behaved like a typical shallow macrotidal estuary, while the lower estuary and the gulf resembled outer shelf seas and ocean slopes, respectively. The EGSL emitted 166.3 (71.5–214.4) × 106 mol CH4 year−1 to the atmosphere, representing 0.3% (0.1%–0.4%) of the total emission from global estuarine environments. A net production of 11.7 × 107 mol CH4 year−1 was required to sustain this emission. Methane distributions in the upper estuary were dominated by physical mixing, while those in the lower estuary and the gulf bore characteristic subsurface maxima and deep minima shedding light on the methane consumption and production pathways. Elevated but highly variable near‐bottom methane concentrations (10.4–695.3 nmol L−1) transpired over pockmarks on the seabed of the lower estuary, inferring an upward diffusive flux of up to ∼700 mmol CH4 m2 d−1. Hypoxia in the lower estuary bottom water had little influence on methane concentrations. Lab incubations yielded methane cycling rates from a net production of 0.0068 nmol L−1 d−1 to net consumption with turnover times of 33.3–263 days. Methane in the EGSL was isotopically enriched with 13C (δ13CCH4: −40.9‰ to −27.4‰ relative to Peedee Belemnite). This study reveals that the EGSL is a smaller proportional contributor to methane emission from estuarine environments and that complex physical‐biogeochemical interactions control methane cycling and isotopic composition in this vast estuarine system. Plain Language Summary: Methane is the second most important greenhouse gas after carbon dioxide. The ocean is a significant source of methane to the atmosphere, with a disproportionally higher share from estuarine and coastal environments. The Estuary and Gulf of St. Lawrence (EGSL) is the largest semi‐enclosed estuarine system in the world. However, methane concentrations and air‐sea fluxes in the EGSL are unknown to date and are thus absent in global‐ocean methane data compilations. We collected a multi‐season and multi‐year data set of methane from the water column of the EGSL to assess methane's distributions, air‐sea fluxes, sources, and cycling in this vast system. Surface‐water methane concentration decreases from the upper estuary to the lower estuary to the gulf. The distribution of methane in the upper is mainly controlled by the mixing of river water with seawater, while the distribution of methane in the lower estuary and the gulf, which are much deeper and wider than the upper estuary, is dictated by oceanic water mass composition and its interaction with different biogeochemical processes. The EGSL accounts for 0.3% of the total methane emission from global estuarine environments, which is a smaller proportional contribution on a per‐surface‐area basis. Key Points: Contrasting methane distributions and dynamics in different subregions of the Estuary and Gulf of St. LawrenceElevated, highly variable methane concentrations in bottom waters near pockmarks but no escape of pockmark methane to the atmosphereBoth methane concentrations and emission rates are at the lower bounds of global estuarine environments [ABSTRACT FROM AUTHOR]

First‐order streams flowing through peatlands receive, carry and transform large amounts of organic carbon, methane (CH4) and carbon dioxide (CO2) but remain poorly documented. The objectives of this study were to (a) identify the origins of CO2 and CH4 (thereafter C‐GHG for carbon greenhouse gases) in a peatland headwater stream, (b) determine the environmental factors driving C‐GHG export and emissions, and (c) quantify C‐GHG losses from this system and discuss its implications. Data were collected from eight sampling sites along a 3 km boreal peatland headwater stream (Eastern Canada) over the growing seasons 2019 and 2020. The studied stream was oversaturated in pCO2 [min: 2,044; max: 23,306 μatm] and pCH4 [14; 17,614 μatm]. A mass balance model showed that ∼81% of in‐stream CO2 originated from porewater seepage while the remaining 17% and 2% originated from in‐stream productivity and methane oxidation, respectively. Porewater seepage was concluded to be the primary source of CH4. Seasonal dissolved C‐GHG concentrations were negatively correlated with the peatland water table depth, suggesting an active release of carbon‐rich peat porewater during the base flow. Nevertheless, greater C‐GHG losses occurred during stormflow periods which acted as pulses with most of the C‐GHG being shunted downstream. The sum of C‐GHG export and emissions at our site was 8.08 gC m−2 y−1 with 86% being released to the atmosphere and 14% being exported downstream. Our study demonstrates that peatland headwater streams act as large sources of C‐GHG and that precipitation events and topography control the magnitude of the fluxes. Plain Language Summary: Headwater streams are the inceptive fragment of the river network where a substantial quantity of organic carbon is released from the surrounding substrate. This terrestrial organic carbon can also be transformed into greenhouse gases (GHGs) such as methane and carbon dioxide. In the stream, those GHG can be either consumed, emitted to the atmosphere, or exported downstream. However, the respective contribution of those pathways is unknown. We sampled a stream draining a rain‐fed peatland in Eastern Canada to describe and quantify its carbon GHG dynamics. We found higher concentrations in this stream than in most headwater streams but the total carbon emissions and export were comparable. Peatland streams typically have a low velocity and gentle slope which minimizes atmospheric gas release. We also found that concentrations were greater during the low flow period, potentially because carbon‐rich porewater was released from the peat. However, greater export was reported during the few days of intense rain. The significance of this work is that GHG in headwater streams are spatially and temporally variable and controlled by the surrounding ecosystems, the intensity of rain events and the stream morphology. The inclusion of this variability will improve regional and global carbon budget estimates. Key Points: Porewater seepage accounted for 81% of the carbon dioxide (CO2) present in the stream, in‐stream production and methane (CH4) oxidation contributed to 17% and 2%86.5% of the dissolved CO2 and CH4 was emitted to the atmosphere rather than exported downstream due to gases oversaturation and slow flow46% of the CO2 and CH4 exported downstream occurred during the 10% period when water discharge rates were maximum, suggesting a pulse effect [ABSTRACT FROM AUTHOR]

Oil and gas exploration has resulted in over 300,000 km of linear disturbances, known as seismic lines, throughout boreal peatlands across Canada. Sites are left with altered hydrologic and topographic conditions that prevent tree re-establishment. Restoration efforts have concentrated on tree recovery through mechanical mounding to re-create microtopography and support planted tree seedlings to block sightlines and deter the use of lines by wolves, but little is known about the impact of seismic line disturbance or restoration on peatland carbon cycling. This study looked at two mounding treatments and compared summer growing season carbon dioxide and methane fluxes to untreated lines and natural reference areas of a wooded fen in the first two years post-restoration. We found no significant differences in net ecosystem CO2 exchange, but untreated seismic lines were slightly more productive than natural reference areas and mounding treatments. Both restoration treatments increased ecosystem respiration, decreased net productivity by 6–21 g CO2 m−2 d−1, and created areas of increased methane emissions, including an increase in the contribution of ebullition, of up to 2000 mg CH4 m−2 d−1 over natural and untreated lines. Further research on this site to assess the longer-term impacts of restoration, as well as application on other sites with varied conditions, will help determine if these restoration practices are effective at restoring carbon cycling. [ABSTRACT FROM AUTHOR]

Area burned, number of fires, seasonal fire severity, and fire season length are all expected to increase in Canada, with largely unquantified ecosystem feedbacks. However, there are few observational studies measuring ecosystem-scale biogeochemical (e.g., carbon dioxide exchanges) and biophysical (e.g., energy partitioning) properties during smoke episodes and hence assessing responses of gross primary production (GPP) to changes in incoming diffuse photosynthetically active radiation (PAR). In this study, we leveraged two long-term eddy covariance measurement sites in forest and wetland ecosystems to study four smoke episodes, which happened at different times and differed in length, over 4 different years (2015, 2017, 2018, and 2020). We found that the highest decrease in shortwave irradiance due to smoke was about 50 % in July and August but increased to about 90 % when the smoke arrived in September. When the smoke arrived in the later stage of summer, impacts on sensible and latent heat fluxes were very different than the earlier ones. Smoke generally increased the diffuse fraction (DF) from ∼ 0.30 to ∼ 0.50 and turned both sites into stronger carbon dioxide (CO2) sinks with increased GPP up to ∼ 18 % and ∼ 7 % at the forest and wetland site, respectively. However, when DF exceeded 0.80 as a result of dense smoke, both ecosystems became net CO2 sources as total PAR dropped to low values. The results suggest that this kind of natural experiment is important for validating future predictions of smoke–productivity feedbacks. [ABSTRACT FROM AUTHOR]

The multi-sector end-use energy model E3MC was used to analyze the energy and greenhouse gas emissions impact of adding a carbon tax to efficiency improvement standards for the residential sector in Canada and the USA. Compared to standards alone, the addition of the tax led to further residential emission reductions in Canada, but attenuated the residential emission reductions in the USA. Examination of the relative residential electricity:natural gas prices demonstrated that the different country impacts were due to an increase in relative prices in the USA, but a decrease in relative prices in Canada that led to opposite shifts in preference for electricity over natural gas in the residential sector. Markedly different impacts of the carbon tax on electricity prices was due to the predominance of hydroelectric power in Canada and coal-fired electric generation in the USA. [ABSTRACT FROM AUTHOR]

In response to growing pressures to reduce the clinker content in cement and hence the CO2 emissions associated with its production, the Canadian Standards Association (CSA A3001-08) introduced a new classification of cement in 2008, this being Portland limestone cement (PLC) containing up to 15% limestone. PLC is now permitted in the production of all classes of concrete in Canada except for sulfate-exposure classes (CSA A23.1-09). Considerable laboratory testing has been conducted in Canada in recent years to demonstrate that PLC with up to 15% limestone can be manufactured to produce equivalent performance to a Portland cement in terms of concrete strength and other properties, including durability. The equivalent performance is achieved by optimizing the PLC with regards to composition and particle-size distribution, and this is achieved by intergrinding rather than blending of the Portland cement and limestone. This paper presents data from a number of recent full-scale field trials where PLC has been used in paving projects in Quebec, Alberta, and Nova Scotia. In each field trial, the performance of PLC concrete has been compared with that of equivalent concrete produced using Portland cement (PC), and concretes have been produced with varying levels (up to 50%) of supplementary cementing materials (SCM). Testing of concrete produced during the field trials has included compressive strength, freeze-thaw and deicer-salt-scaling resistance, chloride permeability, and chloride diffusion. The results indicate that concrete performance is strongly influenced by the level of SCM used, but is independent of whether PLC or PC is used. The use of such PLC has the potential to bring about a 10% reduction in the greenhouse gas emissions associated with the production of Portland cement clinker. The acceptable performance of concrete containing combinations of PLC and SCM will permit further reductions in the CO2 footprint of the concrete; in one mix, the clinker content was just 41% of the total mass of cementing material. [ABSTRACT FROM AUTHOR]

Abstract: This paper will discuss TRIPLEX-Flux, a process-based model that estimates net ecosystem production (NEP) as well as analyzing the level of sensitivity of the model''s response by simulating CO2 flux in an existing old black spruce BOREAS site in central Canada. The research objectives were: (1) to test the TRIPLEX-Flux model simulations against flux tower measurements; and (2) to examine parameter and input variable effects on model response via sensitivity analysis. Validation of NEP data at 30min intervals derived from tower and chamber measurements showed that the NEP data from the model corresponded well with the measured NEP from the BOREAS site (R 2 >0.65). Sensitivity analysis demonstrated different levels of sensitivity between morning and noon periods and from the current to doubled atmospheric CO2 concentrations. Additionally, the comparison of different algorithms to calculate stomatal conductance showed that the NEP predicted by the model using the iteration algorithm was consistent with the results using a constant C i/C a of 0.74 for current and 0.81 for doubled CO2 concentrations. Varying parameter and input variable values by ±10% resulted in a similar model response between morning and noon periods (less than or equal to 27.6% and 27.4%, respectively). Most parameters were more sensitive at noon than they were in the morning except for those that were correlated with air temperature, suggesting that air temperature has considerable influence over model sensitivity for these parameters/variables. Air temperature effect was greater under doubled than it was under current atmospheric CO2 concentrations. In contrast, model sensitivity to CO2 decreased under doubled CO2 concentrations. [Copyright &y& Elsevier]

Abstract: Local-scale wind regimes over an idealized two-dimensional (2D) mountain having similar horizontal and vertical scales as Vancouver Island were investigated using a high-resolution mesoscale model. The model-generated flow outputs were then used as ersatz data to assess the impact of limiting assumptions in the eddy-covariance (EC) method as well as the effectiveness of tower flux data time-filtering for the main tower site of the Fluxnet-Canada British Columbia flux station. In this paper, we describe the simulated mesoscale and local-scale flow regimes, and in Part II we describe their use in assessing tower-data analyses of CO2 fluxes. The numerical model was enhanced to include parameterizations for: tree drag, radiation effects of forest canopies on the surface energy budget, and soil heat conduction. Simulations were performed both over an idealized bare hill and over a forested hill. The simulated flow involved interactions between the land/sea breeze, convective thermals, and mountain circulations under fair-weather conditions. The resulting simulated winds over the forested slope were much weaker than those over a bare slope. The nocturnal drainage flow over the forested slope was separated into sub-canopy and above-canopy regimes due to the temperature inversion at treetop. The strongest downslope flows occurred above the canopy with a minimum velocity occurring in the upper canopy where canopy drag is the strongest. The overturning of large convective eddies during daytime resulted in intermittent downslope flows under the canopy during the day. Wind regimes had a rapid shift from upslope to downslope flow above the canopy just after sunset. Further testing will be made using 3D simulations with higher resolution. [Copyright &y& Elsevier]

Abstract: A long-term flux measurement station has been established in a 74-year-old mixedwood forest ecosystem, located approximately 80km west of Timmins in northern Ontario, as part of the Fluxnet-Canada Research Network (FCRN). Measurements of energy, water vapour, and carbon dioxide fluxes have been made continuously since August 2003 using the eddy covariance technique, along with ancillary meteorological variables. The spatial structure of the site was evaluated using a variety of sources and techniques, including remote sensing, showing that this forest is mixed but relatively homogeneous. The canopy top height is remarkably constant at between 30 and 32m. The basal area varies from 18 to 27m2 ha−1, and the aboveground biomass ranges from 82 to 122Mgha−1. In this paper, we summarize the diurnal and seasonal patters of carbon dioxide exchange and water loss from September 1, 2003 to August 31, 2004. Net ecosystem productivity (NEP) is strongly related to temperature. Atmospheric vapour pressure deficit (VPD) in this ecosystem exerted strong biophysical control on the daily gross ecosystem productivity (GEP) and evapotranspiration. Seasonal change in shortwave albedo, as a result of the presence of mixed deciduous and coniferous species, was clearly evident. Albedo changes were comparable to the seasonal pattern of NEP. The dormant season lasts more than 6 months of the year at this station. This forest was a moderate sink of carbon over the measurement period. Annual values of GEP, ecosystem respiration (R), and NEP were 1075, 919, and 156±35gCm−2, respectively. [Copyright &y& Elsevier]

The article discusses the paper concerning the use of wood for construction and energy in the cities in Canada presented at the international symposium on "The Natural City" on June 23-25, 2004. It is stated that the country ratified the Kyoto Protocol in December 2003 and promised to reduce its greenhouse gas emission, particularly carbon dioxide, by 6% in 2010. According to the author, the country's plan with respect to a climate change would be a challenge and an opportunity to the Canadian forest and wood industry. He believes that the utilization of wood as fuel would substantially repress greenhouse effect.

Climate change in the Arctic is leading to shifts in vegetation communities, permafrost degradation and alteration of tundra surface–atmosphere energy and carbon (C) fluxes, among other changes. However, year-round C and energy flux measurements at high-latitude sites remain rare. This poses a challenge for evaluating the impacts of climate change on Arctic tundra ecosystems and for developing and evaluating process-based models, which may be used to predict regional and global energy and C feedbacks to the climate system. Our study used 14 years of seasonal eddy covariance (EC) measurements of carbon dioxide (CO 2), water and energy fluxes, and winter soil chamber CO 2 flux measurements at a dwarf-shrub tundra site underlain by continuous permafrost in Canada's Southern Arctic ecozone to evaluate the incorporation of shrub plant functional types (PFTs) in the Canadian Land Surface Scheme Including Biogeochemical Cycles (CLASSIC), the land surface component of the Canadian Earth System Model. In addition to new PFTs, a modification of the efficiency with which water evaporates from the ground surface was applied. This modification addressed a high ground evaporation bias that reduced model performance when soils became very dry, limited heat flow into the ground, and reduced plant productivity through water stress effects. Compared to the grass and tree PFTs previously used by CLASSIC to represent the vegetation in Arctic permafrost-affected regions, simulations with the new shrub PFTs better capture the physical and biogeochemical impact of shrubs on the magnitude and seasonality of energy and CO 2 fluxes at the dwarf-shrub tundra evaluation site. The revised model, however, tends to overestimate gross primary productivity, particularly in spring, and overestimated late-winter CO 2 emissions. On average, annual net ecosystem CO 2 exchange was positive for all simulations, suggesting this site was a net CO 2 source of 18 ± 4 g C m -2 yr -1 using shrub PFTs, 15 ± 6 g C m -2 yr -1 using grass PFTs, and 25 ± 5 g C m -2 yr -1 using tree PFTs. These results highlight the importance of using appropriate PFTs in process-based models to simulate current and future Arctic surface–atmosphere interactions. [ABSTRACT FROM AUTHOR]

The residential sector is the third largest end-use energy consumer in Canada. With the increasing pressure on Canada to reduce its energy consumption and the associated carbon dioxide emissions, reducing energy consumption in the residential sector is very important. To quantitatively assess the impact of the large number of measures that can be adopted to reduce the residential energy consumption, a residential energy model for Canada (Canadian Residential Energy End-use Model—CREEM) was developed. This paper presents the model, the characteristics of the residential energy consumption in Canada, and impact of various energy consumption reduction scenarios. © 1998 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Small farm reservoirs are abundant in many agricultural regions across the globe and have the potential to be large contributing sources of carbon dioxide (CO2) and methane (CH4) to agricultural landscapes. Compared to natural ponds, these artificial waterbodies remain overlooked in both agricultural greenhouse gas (GHG) inventories and inland water global carbon (C) budgets. Improved understanding of the environmental controls of C emissions from farm reservoirs is required to address and manage their potential importance in agricultural GHG budgets. Here, we conducted a regional-scale survey (∼ 235 000 km 2) to measure CO2 and CH4 surface concentrations and diffusive fluxes across 101 small farm reservoirs in Canada's largest agricultural area. A combination of abiotic, biotic, hydromorphologic, and landscape variables were modelled using generalized additive models (GAMs) to identify regulatory mechanisms. We found that CO2 concentration was estimated by a combination of internal metabolism and groundwater-derived alkalinity (66.5 % deviance explained), while multiple lines of evidence support a positive association between eutrophication and CH4 production (74.1 % deviance explained). Fluxes ranged from -21 to 466 and 0.14 to 92 mmol m -2 d -1 for CO2 and CH4 , respectively, with CH4 contributing an average of 74 % of CO2 -equivalent (CO2 -e) emissions based on a 100-year radiative forcing. Approximately 8 % of farm reservoirs were found to be net CO2 -e sinks. From our models, we show that the GHG impact of farm reservoirs can be greatly minimized with overall improvements in water quality and consideration to position and hydrology within the landscape. [ABSTRACT FROM AUTHOR]

• Two new advanced configurations for CO 2 capture in pulp mill was investigated. • A rate-based model in ProMax® 4.0 was used for modeling the CO 2 capture process. • Techno-economic assessment was analyzed for the new advanced configurations. • The combined effect of carbon tax and CO 2 sales price on the NBSK price was analyzed. • CO 2 capture plant in pulp mill only led to a slight increase in the NBSK pulp price. This project study involves the techno-economic assessment of two new advanced configurations for amine-based carbon dioxide capture from a pulp mill. The newly proposed advanced configurations include advanced rich amine four split (ARA4S), and advanced rich amine three split with desorber inter-heating (ARA3S-DI) which is aimed at reducing carbon capture cost and carbon emissions. The rate-based model in ProMax® 4.0 was used for the simulation study while the flue gas was provided by a 365,000 air dry tonne of pulp (ADt Pulp) per annum pulp mill in British Columbia, Canada. Comparative analysis revealed that the Capture Cost (US$/tCO 2 and US$/ADt Pulp) of the 5 kmol/m3 MEA system was lowest for the conventional configuration, while for the 2 kmol/m3 AMP-3 kmol/m3 MEA blend it was lowest for the advanced rich amine 3-split with desorber inter-heating configuration. In addition, the Capture Costs of the MEA solution with a conventional configuration system is 8.7% higher than the AMP-MEA blend with advanced rich amine three split with desorber inter-heating configuration. Sensitivity analysis revealed that the combined effect of a carbon tax (US$ 40/tCO 2), CO 2 sales price (US$ 40/tCO 2) and advanced configuration only led to a slight increase (2.6% for MEA and 2.1% for AMP-MEA blend) in the price of the northern bleached softwood kraft pulp. With an even better-performing solvent system and process configuration, the price of NBSK pulp may not be affected given the indicated CO 2 tax and CO 2 price regime. [ABSTRACT FROM AUTHOR]

Greenhouse gases in the atmosphere, mainly carbon dioxide (CO2), can be mitigated by the planting of trees and shrubs. Appropriate agroforestry practices in Saskatchewan include field and farmyard shelterbelts, wildlife plantations, poplar plantations and managed woodlots. A study was conducted to determine the amount of carbon held in prairie shelterbelts. The effect of the soil type and tree species on biomass and carbon content was measured in shelterbelts in the brown, dark brown and black soil zones of Saskatchewan. For some of the main shelterbelt species, the mean aboveground carbon content was 79 kg/tree (32 t/km) for green ash, 263 kg/tree (105 t/km) for poplar, 144 kg/tree (41 t/km) for white spruce and 26 t/km for caragana. Inthe brown and the dark brown soils, which are more arid than the black soil zone, trees had 60.6% and 65.5%, respectively, of the biomassand carbon content of trees and shrubs in the black soil zone. Improved, fast-growing poplar clones had the greatest biomass at maturity and fixed the greatest amount of carbon. Simple equations were developed to calculate the carbon contents of prairie shelterbelts, based on easily measured tree or shrub parameters. This paper will discuss the results of this particular study and the broader implications of this work. [ABSTRACT FROM AUTHOR]

Salt marshes are highly effective carbon (C) sinks and have higher rates of soil C burial (per square meter) than terrestrial ecosystems. Marsh reclamation and anthropogenic impacts, however, have resulted in extensive losses of salt marshes. Restoration of marshes drained and “reclaimed” for agriculture (referred to in Canada as dykelands) and degraded marshes can generate C credits, but only if C burial is reliably quantified. To date, studies reporting on C burial rates have been limited primarily to restored marshes which are more than 10 years old. Here we report on a study which assessed C burial six years after the return of tidal flooding to a section of dykeland in Aulac, New Brunswick on Canada’s Bay of Fundy. The C burial rate in the restored marsh averaged 1 329 g C m-2 yr-1, more than five times the rate reported for a nearby mature marsh. Carbon density in the recovering marsh was relatively consistent with depth and although salt marsh cordgrass (Spartina alterniflora) became established in 2012, the bulk of the C in the new marsh deposit is assumed to be allochthonous. Financial constraints are a barrier to marsh restoration projects and C markets could provide a considerable source of funding for restoration work in the future. For marsh restoration projects to be recognized in C crediting systems, however, it must also be demonstrated that the allochthonous C would not otherwise have been sequestered; the potential for this is discussed. [ABSTRACT FROM AUTHOR]

Background: A major challenge in treating acute asthma exacerbations is the need to open constricted airways rapidly enough to reestablish ventilation and allow delivery of conventional medication to diseased airways. The solution requires a new approach that considers both biophysical and pharmacological aspects of treatments used in acute asthma. The result of testing several formulations was S-1226: carbon dioxide-enriched air delivered in nebulized perflubron, a synthetic surfactant. These agents act synergistically to rapidly reopen closed airways within seconds. The bronchodilator effect is independent of β-adrenergic and cholinergic mediated-signaling pathways, offering a unique mechanism of action. S-1226 has a low toxicity profile and was effective in treating bronchoconstriction in animal models of asthma. The goal of the present study was to evaluate the safety and tolerability of S-1226 in healthy human subjects.Methods: The phase I study was a single-center, randomized, double-blind, placebo-controlled, sequential, single-ascending-dose study conducted in Canada. Thirty-six subjects were distributed into three cohorts. Within each cohort, subjects were randomized to receive a single dose of S-1226 or a matching placebo administered over a 2-minute nebulization period. S-1226 was formulated with perflubron and 4 %, 8 %, or 12 % CO2. The dose of CO2 was sequentially escalated by cohort. The safety and tolerability of S-1226 were evaluated through assessment of adverse events, vital signs, 12-lead electrocardiograms, clinical laboratory parameters, and physical examinations.Results: S-1226 was safe and well tolerated at all three CO2 levels (4 %, 8 %, and 12 %). A total of 28 adverse events were reported, and all were judged mild in severity. Twenty-four adverse events occurred in the S-1226 cohort, of which five were considered remotely related and six possibly related to S-1226.Conclusions: S-1226 is a novel drug being developed for the treatment of acute asthma exacerbations. It consists of CO2-enriched air and perflubron and has potential to offer rapid and potent bronchodilation. The results of the study indicate that S-1226 is safe and well tolerated. All adverse events were mild, reversible, and likely due to known side effects of CO2 inhalation.Trial Registration: ClinicalTrials.gov NCT02616770 . Registered on 25 November 2015. [ABSTRACT FROM AUTHOR]

During 2 years (2009, 2010), CO fluxes were measured in an oligotrophic fen located at the ecotonal limit of forest tundra and lichen woodland, in northeastern Canada. Peatlands in this region have registered a rise in surface moisture since Little Ice Age, allowing an increase in their pool size and density. In the studied peatland, 83 % of the surface is covered either with pools (42 %), hollows (28 %) and lawns (13 %) all of which present a mean water table higher than 7 cm. We evaluated how these conditions might influence the CO balance in these poor fens located in the northeastern section of the La Grande river watershed. During the two years measurements, results indicate a net CO source with 404 (±287) and 272 (±250) g CO myear emitted to the atmosphere throughout the growing seasons and winters. Modeled wintertime net ecosystem exchange resulted in a net loss of 150 (±36) and 150 (±37) g CO m year in 2009 and 2010 respectively, while 248 (±248) and 124 (±195) g CO m was emitted during 2009 and 2010 growing seasons. This high CO source can be attributed to three factors: (1) the length of the cold season which represented 210-214 days of net CO loss (2) a high pool/vegetated surface ratio since pools are a net source of CO and presented 38-40 % of the annual spatially weighted CO budget and (3) hydroclimatic conditions during the growing season as dryer and warmer conditions in 2009 reduced photosynthesis and increased respiration rates. [ABSTRACT FROM AUTHOR]

The Hudson Bay Lowlands (HBL) constitute a globally significant carbon pool; the paleoecological record provides an opportunity to investigate long-term drivers of change in carbon accumulation and related changes in vegetation. We present a Holocene record from the Victor Fen site (VM-3-3) in Ontario's HBL to reconstruct vegetation history, quantify rates of carbon accumulation, and determine the role of paleoclimatic drivers. Pollen analysis indicates initiation of peat accumulation over a mineral substrate, accompanied by relatively rapid rates of carbon accumulation, following emergence from the Tyrrell Sea ∼6900 yrs BP. The earliest vegetation assemblage consisted of a tidal marsh, quickly succeeding to a Typha marsh, then a poor fen dominated by Sphagnum and Cyperaceae by 6400 yrs BP. Rapid rates of isostatic uplift at the time likely contributed to these changes. Once established, this fen community persisted without major vegetation change until the most recent century, when the abundance of shrub and Cyperaceae pollen increased, suggesting increasingly minerotrophic conditions. Average rate of long-term carbon accumulation (LORCA) for the whole record (mean = 22.8 g C m-2 yr-1) is similar to other northern peatlands, and higher than the Holocene average for an adjacent bog. Increased precipitation after ∼2400 yrs BP may have contributed to the higher LORCA reconstructed for the late Holocene, but the increased precipitation did not coincide with any apparent changes in vegetation as inferred from pollen assemblages. [ABSTRACT FROM AUTHOR]