The two-way, complex interactions between urban and geophysical systems has been recently recognised as the key question for the fate our planet and the issue of the Anthropocene. A convincing evidence from UN, including SDG (Sustainable Development Goals,) confirms this challenge: not only the majority of the world population is already urbanised, but this level is expected to reach 80% for the developed countries and 60% in the emerging countries by 2050. In fact, the expected total growth of the world population will be in cities, mainly in the developing
world. Although they cover a small fraction of the earth’s surface, cities consume 80% of the world energy and produce more than 60% of greenhouse gas emissions. Furthermore, most of the infrastructures, facilities and assets are located in cities and, a large fraction of them are under
geophysical threats and/or offer poor basic services and quality of life. The main goal is to shift from traditional management of resources and risks to integrated monitoring of the environment across its wide range of space-time scales and to develop holistic responses to both the ongoing geophysical changes and urbanisation processes, such as increasing the city resilience to geophysical extremes and climate change. This great debate will not only pinpoint the necessary paradigm shifts, e.g. Nature based city developments - such as Blue Green Solutions, Eco-cities combined with sponge cities, and alike -
but also the means to achieve them. In particular, this debate should be a key moment to bridge gaps between concerned disciplines and communities, and generate stimulating synergies, notably between geoscientists, natural and city scientists, engineers and planners, as well as other stakeholders.