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Recycled polylactic acid (PLAr) was reinforced with treated nanocellulosic hemp fibers for biocomposite fabrication. Cellulosic fibers were extracted from hemp fibers chemically and treated enzymatically. Treated nanocellulosic fibers (NCF) were analyzed by Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Biocomposite fabrication was done with PLAr and three concentrations of treated NCF (0.1%, 0.25%, and 1% (v/v)) and then studied for thermal stability and mechanical properties. Increased thermal stability was observed with increasing NCF concentrations. The highest value for Young’s modulus was for PLAr + 0.25% (v/v) NCF (250.28 ± 5.47 MPa), which was significantly increased compared to PLAr (p = 0.022). There was a significant decrease in the tensile stress at break point for PLAr + 0.25% (v/v) NCF and PLAr + 1% (v/v) NCF as compared to control (p = 0.006 and 0.002, respectively). No significant difference was observed between treatments for tensile stress at yield.

Abstract The accelerating sea-ice, ice sheet and glacial melt associated with climate warming have resulted in important changes in the Arctic region over the past decades. In northern Baffin Bay, the formation of the North Open Water (NOW) polynya, which is intrinsically linked to regional sea-ice conditions and ocean circulation, has become more variable in recent years. To understand how climate-driven changes affect sea-surface conditions in the polynya, we analyzed dinoflagellate cyst assemblages from a sediment core record that covers the past ca. 3800 years, and developed an index based on the locations of modern analogues from a large regional reference dataset. Our results suggest a prolonged open-water season characterized by higher summer sea-surface salinity and temperature between ca. 3800 to 2500 years BP, followed by gradual cooling, freshening and increased sea-ice influence from 2500 to 1500 years BP, and continued sea-surface cooling with a shorter open-water season from 1500 to 156 years BP. The modern warming translates into a rapid turnover in the composition of dinoflagellate cyst assemblages during the last 50 years of our record, unprecedented for at least the past 3800 years studied here. For the uppermost part of our core (ca. 2009 to 2015 CE), the dinoflagellate cyst assemblages suggest increased stratification and sea-surface freshening resulting from increased glacial runoff and Arctic sea-ice export into the NOW region. Arctic climate projections indicate accelerated sea-ice thinning and ice sheet melt in the future, pointing to a shorter polynya season and increased polar inflows leading to fundamental changes within the NOW polynya into future years.

This review provides a synthesis of limnological data and conclusions from studies on ponds and small lakes at our research sites in Subarctic and Arctic Canada, Alaska, northern Scandinavia, and Greenland. Many of these water bodies contain large standing stocks of benthic microbial mats that grow in relatively nutrient-rich conditions, while the overlying water column is nutrient-poor and supports only low concentrations of phytoplankton. Zooplankton biomass can, however, be substantial and is supported by grazing on the microbial mats as well as detrital inputs, algae, and other plankton. In addition to large annual temperature fluctuations, a short growing season, and freeze-up and desiccation stress in winter, these ecosystems are strongly regulated by the supply of organic matter and its optical and biogeochemical properties. Dissolved organic carbon affects bacterial diversity and production, the ratio between pelagic and benthic primary productivity via light attenuation, and the exposure and photoprotection responses of organisms to solar ultraviolet radiation. Climate warming is likely to result in reduced duration of ice-cover, warmer water temperatures, and increased nutrient supplies from the more biogeochemically active catchments, which in turn may cause greater planktonic production. Predicted changes in the amount and origin of dissolved organic matter may favour increased microbial activity in the water column and decreased light availability for the phytobenthos, with effects on biodiversity at all trophic levels, and increased channelling of terrestrial carbon to the atmosphere in the form of greenhouse gases.

Ice shelves in the Arctic lost more than 90% of their total surface area during the 20th century and are continuing to disintegrate rapidly. The significance of these changes, however, is obscured by the poorly constrained ontogeny of Arctic ice shelves. Here we use the sedimentary record behind the largest remaining ice shelf in the Arctic, the Ward Hunt Ice Shelf (Ellesmere Island, Canada), to establish a long-term context in which to evaluate recent ice-shelf deterioration. Multiproxy analysis of sediment cores revealed pronounced biological and geochemical changes in Disraeli Fiord in response to the formation of the Ward Hunt Ice Shelf and its fluctuations through time. Our results show that the ice shelf was absent during the early Holocene and formed 4,000 years ago in response to climate cooling. Paleoecological data then indicate that the Ward Hunt Ice Shelf remained stable for almost three millennia before a major fracturing event that occurred ∼1,400 years ago. After reformation ∼800 years ago, freshwater was a constant feature of Disraeli Fiord until the catastrophic drainage of its epishelf lake in the early 21st century.

Guest editorial. This special issue comprises a selection of papers, earlier versions of which were presented at an international colloquium on the possibility of rationing fuel in view of growing greenhouse gas (GHG) emissions. The colloquium was part of the series “Entretiens Jacques Cartier”, held in Lyon (France) in December 2006.

Life Cycle Costing (LCC) is universally accepted as the method of choice for economic assessment in Life Cycle Sustainability Assessment (LCSA) but the singular focus on costs is ineffective in representing the multiple facets of economic sustainability. This review intends to identify other economic indicators to potentially complement the use of LCC in LCSA. Papers for the review were identified in the Web of Science Core Collection database for the years 2010–2021. The shortlisted indicators were analyzed using 18 criteria. The 21 indicators analyzed performed well with respect to the review criteria for indicator methodology and use but most are unsuitable for direct integration into the LCC/LCSA framework due to the inability to aggregate across life cycles and a lack of correspondingly granular data. The indicators were grouped into six economic impact categories—profitability, productivity, innovation, stability, customers, and autonomy—each of which represents a significant aspect of economic sustainability. On this basis, a conceptual framework is proposed that could maintain the utility of LCC while integrating additional indicators to enable more holistic economic assessments in LCSA. Considering additional economic indicators in LCSA ensures that the positive aspects of LCC are preserved while also improving economic assessment in LCSA.

The article aims to present the discussions about sustainability and corporate social responsibility. Such concepts are no longer a trend and are in continuous process of construction, even if the discussions on the subject have gained more proportion in the last decades. It is possible to relate them to the financial results of organizations. And in fact, these concepts are not static, but rather require an ongoing process of redefinition, which now involves a vision of long-term corporate strategy. Organizations have been pushed to change the way they are committed not only to the environmental issue, but especially to how committed they are to society. In this way, corporate social responsibility has grown and is one of the organizations’ priorities. It is considered that these organizations face a new risk scenario, which demands the adoption of a socially and environmentally responsible position, converging towards economic efficiency. Thus, the present analysis was based on bibliographic references using the hypothetical deductive method.