By 2050, the United Nations foresees an increase in the population in cities up to 74% in Europe, which is why the next decade has been named by the UN as the Decade of Action - ten years to change our world before an irreparable worsening of the already critical issues linked to the impacts that urban centers have on the environment (from the unsustainable consumption of resources to the increase in the production of waste or emission of pollutants). This change is necessary to avoid a catastrophic worsening of the current situation, but it will not be possible unless cities adopt new policies and priorities.

In the Metropolitan City of Bologna a concrete example of these new policies and priorities are the strategic guidelines for transforming cities inspired by the European Urban Agenda partnership. The validity of the Bologna-supported partnership for sustainable land use and NBS, which started in June 2017, with the aim of identifying relevant actions to reduce urban sprawl and land consumption on the one hand, and on the other, integrate the introduction of nature, and natural features and processes, into cities, has now received explicit recognition at international level thanks to the publication of the European Commission's DG for Regional and Urban Policies "The Green City Dimension. Making use of circular procurement and specific targets and indicators".

The paper recognizes that it is a priority for Bologna to build the conditions to make its area increasingly healthy and resilient, where risks to people and the environment are reduced, where biodiversity is protected and the ecosystem function of green infrastructure is improved, and, more generally, the quality of the territory and the well-being of citizens.

To this end, a set of common indicators has been proposed to take into account urban greening, renaturation processes and soil sealing/de-sealing, and to provide a common framework for assessing the environmental impact of spatial planning.

In this framework, the activities of the VEG-GAP project in its pilot city of Bologna will align with the mitigation and adaptation strategy for climate change of the whole metropolitan area, providing with its vegetation scenarios useful background data on the effects of these processes.

In particular, within its new Metropolitan Agenda for Sustainable Development 2.0, a document which aims at full integration with all the planning and programming tools of the Metropolitan City of Bologna, the possible contribution of the VEG-GAP project has already been explicitly acknowledged in the definition of a cognitive framework on the green systems endowment.

The ambition is that this combination of actions for a sustainable use of soil and the promotion of tools and methodologies for an innovative study of urban green areas can also actively contribute to the compliance in the metropolitan area with the limits for PM 10 and fine particulate matter (PM 2.5) of 10 μg/mc by 2025, as indicated in its Agenda 2.0 in Target 11.6 "Air Quality".