Anthropocene and magnitude of geomorphological changes in the urbanization process in the metropolis of São Paulo, Brazil

Research conducted over the last 30 years has explored the potential of Geomorphology and its emerging subfield, Anthropogenic Geomorphology, in discriminating the origin and magnitude of changes in geomorphological systems over centuries-old time intervals, particularly related to the Great Acceleration stage. The main type of intervention considered was the urbanization of the metropolitan region of São Paulo, in terms of direct interventions and their effects, considering as main references the typical fluvial geomorphological systems of plateaus in the humid tropical environment of southeastern Brazil: river basins, fluvial-lacustrine systems, fluvial channels, floodplains and fluvial terraces. The types of geoindicators used in this methodology were morphological-morphometric, surface materials and process indicators, which revealed significant discriminatory potential in relation to the origin of the changes and their magnitude. In terms of magnitude, the changes observed were compatible with the phases of geomorphological adjustments of the inputs of matter and energy generated by tectonic actions and climate change. Changes were identified in the geoindicators of river channels, such as: decrease of 30% to 47% in the length of channels, increase of 420% in the cross-section area of channels, increase of up to 2233% in the magnitude of extreme flows and loss of floodplain area of up to 99%, among other robust results revealing the high magnitude of direct interventions and their effects. The researches also revealed relevant results for the dimensioning of the magnitude of losses of ecosystem services of river plains in the metropolis of São Paulo.