Impacts of Climate Change on Water Surplus and Deficit in the State of Paraíba, Brazil

Climate change has impacted water availability in several regions of the earth, especially semi-arid regions. The northeastern region of Brazil is particularly vulnerable to such changes due to its high temperatures and uneven rainfall distribution. The State of Paraíba comprises four distinct mesoregions: Mata Paraibana, Agreste Paraibano, Borborema, and Sertão Paraibano, with different rainfall regimes. In this work, the objective is to map the regions of the state of Paraíba most vulnerable to climate change based on the analysis of the water balance. This study aimed to quantify water availability for the state and identify the year in which this change occurred in the historical record of water surplus and deficit. Therefore, we consider two periods of study: the first from the beginning of the historical series until the year of change; the other from the next year after the change point until 2020. Additionally, it sought to determine the variables that most influenced these changes, thereby presenting the regions of the state most vulnerable to these changes. Climate change has impacted water availability in several regions of the earth, especially semi-arid regions. The results show that the regions of Agreste, Borborema, and Sertão Paraibano are the most vulnerable, presenting a negative balance in both periods. The surplus and deficit showed a reduction and increase, influenced mainly, in the first period, by precipitation. During the second period, cities were influenced by temperature, relative humidity, and sunshine. The land use/land cover change is also a factor that contributes to the reduction in the amount of water in the soil.