Although still encouraged by UN-Habitat (UN-HABITAT, 2020; 2021), with the paradigmatic example of Barcelona, the compact city model – briefly: high density and mixed-use pattern–is increasingly criticized (DAOU, 2016; BERTAUD, 2018). It is not a matter of adding controversy to the discussion here, as some studies (RUSSO, CIRELLA, 2018; UN-HABITAT, 2021) have already pointed out the need for a balance between density and urban green space (UGS). Urban density and compactness are desirable from the point of view of infrastructure and transport costs, but not very good for ecology and health. In this direction, a recent study by Swedish researchers first looked at the Swedish planning practice and then compared three hundred articles on the subject across the world (HAUPT et. al, 2020; BERGHAUSER PONT et al, 2020) practically ends the discussion. As Russo and Cirella (2018, p.1-2) note “compact cities that have an overall lower percentage of UGS demonstrate to lack ecosystem services. Moreover, such cities are the most impacted by the heat island effect and the resulting consequences from urban densification”. In this direction, the title of the last publication by UN-Habitat (UN-HABITAT, 2021) makes clear the way forward: “Cities and Pandemics: Towards a More Just, Green and Healthy Future”.
Anyway, at the other pole of the UN-Habitat defense of the compact city model, consecrated names in the study of urban density as Shlomo Angel and Alain Bertaud, supported by empirical research, models, and data analysis, point out some aspects often neglected by the blind defense of a simplistic view of the model, the compact city as a panacea for the problems raised by urban growth and expansion – “sprawl” – in all situations, geographies and scales.