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As the vegetation in the Arctic changes, tundra ecosystems along the southern border of the Arctic are becoming greener and gradually giving way to boreal ecosystems. This change is affecting local populations, wildlife, energy exchange processes between environmental compartments, and the carbon cycle. To understand the progression and the implications of this change in vegetation, satellite measurements and surface models can be employed. However, in situ observational data are required to validate these measurements and models. This paper presents observational data from two nearby sites in the forest–tundra ecotone in the Tasiapik Valley near Umiujaq in Northern Quebec, Canada. One site is on a mixture of lichen and shrub tundra. The associated data set comprises 9 years of meteorological, soil and snow data as well as 3 years of eddy covariance data. The other site, 850 m away, features vegetation consisting mostly of tall shrubs and black spruce. For that location, 6 years of meteorological, soil and snow data are available. In addition to the data from the automated stations, profiles of snow density and specific surface area were collected during field campaigns. The data are available at 10.1594/PANGAEA.964743 (Domine et al., 2024). [ABSTRACT FROM AUTHOR]

Draining and extracting peat alters the conditions that control CO 2 and CH 4 emissions. Carbon (C) emissions from peatlands undergoing horticultural peat extraction are not well constrained due to a lack of measurements. We determine the effect that production duration (years of extraction) has on the CO 2 and CH 4 emissions from an actively extracted peatland over 3 years of measurements (2018–2020). We studied five sectors identified by the year when extraction began (1987, 2007, 2010, 2013, 2016). Greater average CO 2 and CH 4 emissions were measured from the drainage ditches (CO 2 : 2.05 ± 0.12 g C m -2 d -1 ; CH 4 : 72.0 ± 18.0 mg C m -2 d -1) compared to the field surface (CO 2 : 0.9 ± 0.06 g C m -2 d -1 ; CH 4 : 9.2 ± 4.0 mg C m -2 d -1) regardless of sector. For peat fields, CO 2 fluxes were highest in the youngest sector, which opened in 2016 (1.5 ± 0.2 g C m -2 d -1). The four older sectors all had similar mean CO 2 fluxes (∼ 0.65 g C m -2 d -1) that were statistically different from the mean 2016 CO 2 flux. A spatial effect on CO 2 fluxes was observed solely within the 2016 sector, where CO 2 emissions were highest from the centre of the peat field and declined towards the drainage ditches. These observations occur due to operators contouring surfaces to facilitate drainage. The domed shape and subsequent peat removal resulted in a difference in surface peat age hence different humification and lability. In addition, 14 C dating confirmed that the peat contained within the 2016 sector was younger than peat within the 2007 sector and that peat age is younger toward the centre of the field in both sectors. Humification indices derived from mid-infrared spectrometry (MIRS) (1630/1090 cm -1) indicated that peat humification increases with increasing years of extraction. Laboratory incubation experiments showed that CO 2 production potentials of surface peat samples from the 2016 sector increased toward the centre of the field and were greater than for samples taken from the 1987 and 2007 sectors. Our results indicate that peatlands under extraction are a net source of C, where emissions are high in the first few years after opening a field for extraction and then decline to about half the initial value and remain at this level for several decades, and the ditches remain a 2 to 3 times greater source than the fields but represent <3.5 % of the total area of a field. [ABSTRACT FROM AUTHOR]

Several studies have shown the benefits of using timber in the construction sector in terms of climate change, which has received the support of decision-makers. However, few studies focus on other environmental indicators. The environmental impacts (i.e., such as human health, ecosystem quality, and resources) of material substitutions, consequence of the increasing use of wood, are still lacking in the literature. Studies that compare different structural materials focus either on a single building or on one structural system that would be representative on a larger scale. However, the environmental benefits of some projects are not easily extrapolated to the scale of a given region with a variety of architectures. Higher-order effects, beyond the building scale, can indeed imply changes in the resource availability according to the unconstrained suppliers and resources. The objective of this paper is to assess the life cycle environmental consequences of wood substitutions at a regional scale for the non-residential construction sector. The increasing use of wood structures for non-residential buildings in the province of Quebec (Canada) is used as a case study. The method includes the development of material substitution factors by comparing several structures. The substitution factors show that, on average, wood can replace, simultaneously, 0.59 and 4.54 times the weight of steel and concrete, respectively. However, steel substitution has more advantages than concrete substitution. Among the tested parameters, the variability of the material substitution factors implies more uncertainties in the results. The originality of our study lies in the limitations that may change the conclusions drawn from the substitution at a large scale. With three substitution scenarios for four impact categories, the results showed an advantage of using wood in seven of the twelve combinations. The ecosystem quality indicator is the most unfavorable and shows opposite trends to climate change, human health, and resource indicators. Considering average material substitution factors combined with the maximum potential use of wood in non-residential (NR) structures in Quebec in 2050, wood can contribute to avoid 2.6 Mt of carbon dioxide equivalent (CO 2 eq.). This amount is equivalent to 3.5% of Quebec's CO 2 eq. emission reduction target by 2050 compared to 1990. • The environmental consequences of wood substitution at the regional level for the non-residential sector are assessed. • The average scenario suggests that the use of wood can avoid up to 2.62 Mt of CO 2 eq. in 2050. • The variability of material substitution factors implies the greatest variability in the results. • With three substitution scenarios for four impact categories, the results showed an advantage for wood increased use in seven of the twelve combinations. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization, and storage (CCUS) is an attractive technology for the decarbonization of global energy systems. However, its early development stage makes impact assessment difficult. Moreover, rising popularity in carbon pricing necessitates the development of a methodology for deriving carbon abatement costs that are harmonized with the price of carbon. We develop, using a combined bottom-up analysis and top-down learning curve approach, a levelized cost of carbon abatement (LCCA) model for assessing the true cost of emissions mitigation in CCUS technology under carbon pricing mechanisms. We demonstrate our methodology by adapting three policy scenarios in Canada to explore how the implementation of CO2-to-diesel technologies could economically decarbonize Canada's transportation sector. With continued policy development, Canada can avoid 932 MtCO2eq by 2075 at an LCCA of CA$209/tCO2eq. Technological learning, low emission hydroelectricity generation, and cost-effective electricity prices make Quebec and Manitoba uniquely positioned to support CO2-to-diesel technology. The additional policy supports beyond 2030, including an escalating carbon price, CO2-derived fuel blending requirements, or investment in low-cost renewable electricity, which can accelerate market diffusion of CO2-to-diesel technology in Canada. This methodology is applicable to different jurisdictions and disruptive technologies, providing ample foci for future work to leverage this combined technology learning + LCCA approach. [ABSTRACT FROM AUTHOR]