A carregar...
2 resultados
Resultados da pesquisa
A mostrar 1 - 2 de 2
- Is carbon dioxide removal in the Arctic region really feasible?Publication . Leal Filho, Walter; Luetz, Johannes; Dinis, Maria Alzira Pimenta; Hunt, Julian; Nagy, GustavoThe Arctic region, warming at nearly four times the global average rate, is both an important carbon sink and a potential source of greenhouse gas emissions, especially due to thawing permafrost. Carbon dioxide removal (CDR) is increasingly recognised as a necessary measure to support global efforts to reduce emissions. This article examines whether, and under what conditions, large-scale CDR deployment in the Arctic is practically feasible. It also discusses the challenges associated with it. We synthesise peer-reviewed evidence on the performance of key CDR approaches relevant to high-latitude environments, including nature-based solutions (NbS), e.g. peatland restoration, blue carbon protection and afforestation, as well as enhanced rock weathering (ERW), ocean alkalinity enhancement (OAE) and direct air carbon capture and storage (DACCS). Across these approaches, the feasibility is constrained by permafrost dynamics, hydrology, ecological sensitivity, energy availability, monitoring and verification, and governance. Whereas some CDR methods offer potential climate benefits, most are characterised by considerable uncertainty and context-dependent trade-offs. None currently demonstrates unequivocal feasibility at scale under Arctic conditions. Beyond these technical and ecological constraints, we identify four clusters of socio-political barriers that further complicate Arctic CDR: governance fragmentation, geopolitical tensions, inadequate regulatory mechanisms, and uneven global deployment. A comparative assessment suggests that peatland restoration and blue carbon protection are the most immediately actionable options, whereas DACCS and OAE would require substantial new infrastructure and energy investment. The study concludes by outlining targeted policy and research priorities to address existing technological, ecological, and governance challenges, and to situate Arctic CDR within broader mitigation strategies without risking over-reliance or mitigation deterrence. The novelty of this paper lies in its analysis of the multiple variables that influence the viability of CDR. Overall, Arctic CDR appears technically possible but remains highly constrained, with its feasibility contingent on meeting stringent operational conditions, robust governance, and continued emissions reductions elsewhere.
- Managing space debris: risks, mitigation measures, and sustainability challengesPublication . Leal Filho, Walter; Dinis, Maria Alzira Pimenta; Hunt, Julian; Abubakar, Ismaila RimiSpace debris consists of non-functional, human-made objects remaining in Earth's orbit or entering the atmosphere, creating significant challenges for space operations. Current surveillance systems track nearly 40,000 larger debris fragments, yet it is estimated that hundreds of thousands of smaller pieces and millions of tiny, untracked particles further contribute to the risk of high-velocity collisions. These objects threaten spacecraft integrity, satellite functionality, and the long-term sustainability of space activities. This review article investigates the hazards posed by space debris, providing an overview of its impact on satellite operations, crewed space missions, and orbital stability. It examines risk mitigation strategies, including the enforcement of stricter disposal regulations, advancements in satellite design for controlled re-entry or deorbiting, and the active removal of large debris objects. A structured approach to space debris mitigation is also explored, outlining a proposed four-step strategy: designing spacecraft for impact resistance, implementing advanced remote tracking and monitoring systems, integrating onboard detection and avoidance mechanisms, and developing impact mitigation strategies to minimize damage. Additionally, the importance of enhanced tracking technologies and international cooperation is underscored, as collective efforts are necessary to address this escalating issue. Increasing awareness of the growing risks and exploring practical mitigation strategies strengthens ongoing efforts to safeguard space activities and ensure the long-term viability of Earth's orbital environment.