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The main driving forces on the development of eco-friendly wood adhesives are based on environmental sustainability, costs savings, recyclability, reusability and health benefits, in comparison with synthetic resins. Lignin, tannin, proteins and carbohydrates are the main renewable raw materials being studied. Taking as a premise the technical performance of different bio-based alternatives, in comparison with formaldehyde-based resins, it is necessary to evaluate the environmental profile of such products in order to assess the pros and cons. In this regard, this manuscript addresses the industrial-scale design and environmental evaluation, through the Life Cycle Assessment methodology, of four formaldehyde-free bio-adhesives. For this purpose, the use of renewable resources such as Organosolv (OSL) and kraft (KL) lignins, soy (SPI) and tannins (MT)), crosslinked and hardened with NIPU (non-isocyanate polyurethanes) were considered. The impact results obtained showed that OSL-NIPU bio-adhesive, with a single environmental score of 35.27 mPa, has the best environmental profile, followed by SPI-NIPU, with a value of 63.36 mPa. Therefore, both could be considered as potential substitutes for synthetic resins. On the other hand, it has been identified that hexamethylenediamine (HDMA), used as crosslinking agent for the formulation of the bio-adhesives, is one of the main hotspots of the environmental profiles of OSL, KL and MT NIPU bio-adhesives. In the case of SPI-NIPU adhesives, it is the soy protein isolation process that leads to a higher environmental contribution. Thus, future research should focus on trying to reduce the dose of HMDA and on improving the soy protein isolation process This research has been financially supported by ERA-CoBIOTECH project (PCI2018–092866) Programación Conjunta Internacional 2018-WOODBADH project. The authors belong to the Galician Competitive Research Group (GRC ED431C 2017/29) and to the Cross-disciplinary Research in Environmental Technologies (CRETUS Research Center, ED431E 2018/01) SI

Currently, most of the greenhouse gas (GHG) emissions are attributed to cities, as they are the global centers of business, residential and cultural activity, cities are expected to play a leading role in proposing climate change mitigation actions. To do so, it is important to have tools that allow the carbon footprint of cities to be assessed as accurately as possible. This study aims to quantify the carbon footprint (CF) associated with the activities developed in a Spanish city (Cadiz, Southwest Spain) by means of two available environmental methodologies, namely Environmentally Extended Input-Output Analysis (EEIOA) and Life Cycle assessment (LCA). When EEIOA is considered, two downscaling factors were proposed for the analysis due to the nature of the data handled (monetary data), based on the incomes (DF1) and expenditures (DF2) per inhabitant at city level. Regarding LCA, the rates of consumption of goods and production of waste per inhabitant have been processed to estimate the CF. The CF scores identified were 5.25 and 3.83 tCO2-eq·inhabitant-1·year-1 for DF1 and DF2 respectively, according to EEIOA, and 5.43 tCO2-eq·inhabitant-1·year-1, considering LCA. Therefore, a similarity can be concluded between the results obtained with both methodologies despite the inherent differences. Considering the results, the downscaling procedure based on income per inhabitant should be preferred, pointing to EEIOA as a good alternative to LCA for evaluating the CF at city level, requiring less time and effort. In contrast, EEIOA reports more limitations when critical flows were identified, which LCA can solve. Finally, this study can be of great interest to policy makers and city governments to know the CF and the main flows that contribute and in this way, can develop new policies and city models for reducing GHG emission new policies and city models for reducing GHG emission and addressing climate change. published