The accelerated growth of urban frontiers over natural areas contributes to the faster exploitation of natural resources, generating biodiversity loss and climate change. The overpopulated regions' conurbation generates the emergence of megacities, megalopolises, macro metropolises and megaregions. These areas occupy a vast territory, replacing natural areas with waterproofing urban areas, which increases problems related to biodiversity loss, ecosystem services provision, climate regulation, and generating risks of water crises for a large portion of the population. In some regions of the world, such as North America, Latin America and the Caribbean, more than 80% of the population lives in urban environments, indicating that cities are in full growth and conurbation, affecting the hydrological cycle and the rainfall regime on a global scale. However, although precipitation plays a vital role in the hydrological cycle, recent studies demonstrate that decadal precipitation trends do not necessarily determine the observed trends in terrestrial water storage, which largely depends on the distribution of vegetation cover. In this way, we hypothesized that the greater vegetation cover inside and around urban complexes favours the stability of terrestrial water storage trends. Therefore, we will investigate and understand the effects of the growth of megacities and their disturbance in the green belts on the availability of ecosystem services quantifying water. We will analyze whether the effect of urban growth on natural areas generates consequences for the hydrological cycle and risks to the population's water security. Therefore, the regions to be sampled will be classified into three distinct groups: 1) expanding urban areas, 2) stagnant urban areas, and 3) populated regions with rural or natural areas larger than the urban area. We will use climate data such as temperature, precipitation, and estimated terrestrial water storage from Gravity Recovery and Climate Experiment (GRACE) mission data, together with land use and occupation. We will identify trends in terrestrial water storage and their relationships with climatic, demographic and vegetation cover variables. At the end of the project, it is expected to improve understanding of processes related to water availability, enabling and facilitating discussions and propositions for decision-makers.
News published in Agência FAPESP Newsletter about the scholarship: