O impacto das mudanças climáticas na modelagem do fósforo no reservatório Orós, Ceará (Brasil)

Abstract

Climate change has a direct impact on water quality. In recent years, specific concerns have arisen about the impacts of climate change on changes in nutrient concentrations in water, which pose global environmental challenges in relation to the management of water resources. According to the COGERH trophic state monitoring bulletin, in May 2022, the dams classified as hypereutrophic and eutrophic corresponded to 78.7% of the evaluated dams. There is, therefore, a great deterioration in the quality of water in the reservoirs of Ceará with regard to the concentration of nutrients, generating impacts on environmental, economic and public health aspects.The objective of this work is to propose a methodology in order to relate the impact of climate change with the concentration of phosphorus in the Orós reservoir, located in the Alto Jaguaribe basin for the periods 2015-2044; 2045- 2074 and 2075-2100. The methodology consists of coupling climate models from the Coupled Model Intercomparison Project version 6 (CMIP6) with the Soil Moisture Acounting Procedure (SMAP) hydrological model to obtain the flow series. Four global models were used to prepare the study, namely: CSM2, ESM2, HADGEM3 and MIROC6. Its results were obtained for emission forcing scenarios SSP 2 - 4.5, considered moderate, and SSP 5 -8.5 , considered extreme. The future precipitation and temperature series up to 2100 and the historical series of these models from 1984 to 2014 were obtained to carry out bias correction procedures and also to evaluate the models. It appears that the ESM2 and CSM2 models point to a decrease in future storage and the HADGEM 3 and MIROC6 models point to an increase in storage. The SSP5-8.5 scenario increases the aggravation of trends in relation to the SSP2-4.5 scenario with greater reductions and greater increases. The deterioration of water quality was more serious in the last evaluated period (2075- 2100) and for the SSP5-8.5 scenario, as they are the combination that presents the lowest flowsThe projected increases in the concentration of phosphorus have a direct impact on the environmental sanitation of the hydrosystem as it can result in: an increase in the proliferation of algae, risk to public health, reduction of biodiversity and increases in the difficulty of managing resources.