Lately, the model of circular economy has gained worldwide interest. Within its concept, waste is viewed as a beneficial resource that needs to be re-introduced in the supply chains, which also requires the use of raw materials, energy, and water to be minimized. Undeniably, a strong link exists between the bioeconomy, circular economy, bioproducts, and bioenergy. In this light, in order to promote a circular economy, a range of alternative options and technologies for biowaste exploitation are currently available. In this paper, we propose a generic methodological scheme for the development of small, medium, or large-scale units of alternative biowaste treatment, with an emphasis on the production of bioenergy and other bioproducts. With the use of multi-criteria decision analysis, the model simultaneously considers environmental, economic, and social criteria to support robust decision-making. In order to validate the methodology, the latter was demonstrated in a real-world case study for the development of a facility in the region of Serres, Greece. Based on the proposed methodological scheme, the optimal location of the facility was selected, based on its excellent assessment in criteria related to environmental performance, financial considerations, and local acceptance. Moreover, anaerobic digestion of agricultural residues, together with farming and livestock wastes, was recommended in order to produce bioenergy and bioproducts.

Globalisation combined with high urbanisation trends affects not only the traditional pillars of sustainability (environment, society, and economy), but also local identity. Customs and traditions are fading away and alienation is the result of new lifestyles deriving mainly from high interaction between locals and foreigners (focus on tourism). Facing the challenge of characterising urban sustainability, reflection on special characteristics of the urban fabric that are affected (spatial dimension of sustainability) is not always considered. Even though a lot of research is dedicated to the characterisation of urban areas’ sustainability, the element of local, regional, and macro-regional identity seems not to be systematically incorporated. This work attempts to develop and test a methodological framework to identify and prioritise the common symbolic elements that constitute the identity of a group of cities and that need to be sustained. The study focuses on the Euro-Mediterranean region. A survey is addressed to 64 scientists from five cities: Dubrovnik, Genoa, Rhodes, Valencia, and Venice. “Urban structure” is revealed as the most important element that constitutes the “Mediterranean identity”. Moreover, the level of threat deriving from mass tourism on the “Mediterranean identity” is estimated. The survey provides insight into the definition of the spatial dimension of sustainability and the determination/weighting of the case-specific component of an integrated urban sustainability assessment tool.

The transition to a circular economy (CE) is a cornerstone of sustainable urban development, directly addressing environmental, social, and economic challenges. This article explores the varied approaches to CE adopted by six European cities - Guimarães, Lisbon, Riga, Oulu, Munich, and Malmö - highlighting their innovative initiatives in digitalization, awareness raising, governance schemes, waste management, public procurements, mapping of flows, and the exploitation of unused spaces. By analyzing these domains, this article provides actionable insights for cities aiming to enhance sustainability through CE practices.

Mediterranean cities, having already suffered from climate change and at risk of being further affected if actions are not taken, need to reduce their emissions and set themselves on a path towards achieving the Paris Agreement ambition of limiting global warming to 1.5 °C. There are several methodologies that have been developed recently for cities in order to set a science-based target in line with a 1.5 °C scenario, that can be adopted by Mediterranean cities. In this short communication, we have selected to refer to two of them with the aim of inspiring experts from Mediterranean cities and providing relevant tools and further learning resources in order to make this task achievable. The new framework is guiding cities towards a greener and more sustainable transition. With a concrete framework to limit greenhouse gas emissions, the Mediterranean Basin can follow the global push to net-zero emissions by mid-century.

This paper presents the outcomes of the project titled: ‘’Feasibility Study for a Black Sea SDGs Observatory’’, financed by the Black Sea Project Promotion Facility. The project was assigned to the Aristotle University of Thessaloniki and the Financial University of Russia. The Observatory will constitute one of the main divisions of the regional UN SDSN (United Nations Sustainable Development Solutions Network) Black Sea. The paper presents the need for establishing a Black Sea SDGs (Sustainable Development Goals) Observatory, the methodology followed, and the expected results of its creation.