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Rising greenhouse gas emissions embodied in the global bioeconomy supply chain
The bioeconomy is key to meeting climate targets. Here, we examine greenhouse gas emissions in the global bioeconomy supply chain (1995–2022) using advanced multi-regional input-output analysis and a global land-use change model. Considering agriculture, forestry, land use, and energy, we assess the carbon footprint of biomass production and examine its end-use by provisioning systems. The footprint increased by 3.3 Gt CO2-eq, with 80% driven by international trade, mainly beef and biochemicals (biofuels, bioplastics, rubber). Biochemicals showed the largest relative increase, doubling due to tropical land-use change (feedstock cultivation) and China’s energy-intensive processing. Food from retail contributes most to the total biomass carbon footprint, while food from restaurants and canteens account for >50% of carbon-footprint growth, with three times higher carbon intensity than retail. Our findings emphasize the need for sustainable sourcing strategies and that adopting renewables and halting land-use change could reduce the bioeconomy carbon footprint by almost 60%.
Low-carbon ammonia production is essential for resilient and sustainable agriculture
Ammonia-based synthetic nitrogen fertilizers (N fertilizers) are critical for global food security. However, their production, primarily dependent on fossil fuels, is energy- and carbon-intensive and vulnerable to supply chain disruptions, affecting 1.8 billion people reliant on either imported fertilizers or natural gas. Here we examine the global N-fertilizer supply chain and analyse context-specific trade-offs of low-carbon ammonia production pathways. Carbon capture and storage can reduce overall emissions by up to 70%, but still relies on natural gas. Electrolytic and biochemical processes minimize emissions but are 2–3 times more expensive and require 100–300 times more land and water than the business-as-usual production. Decentralized production has the potential to reduce transportation costs, emissions, reliance on imports and price volatility, increasing agricultural productivity in the global south, but requires policy support. Interdisciplinary approaches are essential to understand these trade-offs and find resilient ways to feed a growing population while minimizing climate impacts.
Temporal dynamics and global flows of insect invasions in an era of globalization
Human-mediated transport has led to the establishment of more than 6,700 non-native insect species with wide-ranging effects on ecosystems, economies and human health. Understanding how different aspects of globalization affect the spread of non-native insects is crucial to reducing their effects. In this Review, we explore current and historical patterns, drivers and dynamics of global insect invasions facilitated by humans since prehistory. Multiple aspects of the history of globalization have influenced invasion dynamics, including the spread of agricultural practices in the Neolithic period, the advent of early empires and their trade routes, colonization, geopolitical events, wars and economic crises. Technological innovations such as steam ships, containerization and the internet have further accelerated global insect invasions. Spatial invasion patterns are characterized by frequent secondary spread via bridgehead populations, asymmetric intercontinental species flows originating disproportionally from Europe, and biotic homogenization of communities. Insect invasions are predicted to increase dramatically and their dynamics will shift, especially with the opening of trade routes and introduction pathways. Inspection at ports of entry and early detection systems are crucial to inform mitigation efforts. Future interdisciplinary collaborations will integrate knowledge from diverse and emerging data sources and technologies, advancing our understanding of insect invasion biology.
Sustainable supply chain management practices and performance: The moderating effect of stakeholder pressure
Currently, sustainable supply chain management practices have become an important strategy for firms to improve performance and gain competitive advantage. However, there is a current debate over the performance outcomes of sustainable supply chain management practices. Additionally, the role of stakeholder pressure is frequently overlooked. Drawing on Natural Resources-Based View and Stakeholder Theory, this study aims to elucidate the ambiguous connection between sustainable supply management, sustainable process management, stakeholder pressure and performance, and investigate the mediation role of sustainable process management and the moderation effect of stakeholder pressure. Our analysis, based on data collected from 235 Chinese manufacturing firms, reveals significant insights. First, stakeholder pressure positively moderates the relationship between sustainable process management and performance, while negatively moderates the relationship between sustainable supply management and performance. Second, sustainable process management has a complete mediation effect on the relationship between sustainable supply management and performance. The conclusion not only explains the inconsistent relationship between sustainable supply chain management practice and performance, but also reveals clearly the relationship between sustainable supply management and sustainable process management. Besides, it also highlights the difference in performance outcomes of sustainable supply management and sustainable process management under stakeholder pressures, and has valuable guidance to the practice of sustainable supply chain management in Chinese manufacturing firms.
Single cell dynamics and nitrogen transformations in the chain forming diatom Chaetoceros affinis
Colony formation in phytoplankton is often considered a disadvantage during nutrient limitation in aquatic systems. Using stable isotopic tracers combined with secondary ion mass spectrometry (SIMS), we unravel cell-specific activities of a chain-forming diatom and interactions with attached bacteria. The uptake of 13C-bicarbonate and15N-nitrate or 15N-ammonium was studied in Chaetoceros affinis during the stationary growth phase. Low cell-to-cell variance of 13C-bicarbonate and 15N-nitrate assimilation within diatom chains prevailed during the early stationary phase. Up to 5% of freshly assimilated 13C and 15N was detected in attached bacteria within 12 h and supported bacterial C- and N-growth rates up to 0.026 h−1. During the mid-stationary phase, diatom chain-length decreased and 13C and 15N-nitrate assimilation was significantly higher in solitary cells as compared to that in chain cells. During the late stationary phase, nitrate assimilation ceased and ammonium assimilation balanced C fixation. At this stage, we observed highly active cells neighboring inactive cells within the same chain. In N-limited regimes, bacterial remineralization of N and the short diffusion distance between neighbors in chains may support surviving cells. This combination of “microbial gardening” and nutrient transfer within diatom chains represents a strategy which challenges current paradigms of nutrient fluxes in plankton communities.
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