Efeitos das mudanças do clima e desmatamento no regime hidroclimático da bacia do Rio Madeira

Abstract

The significance of evaluating climate models for current climatic conditions lies in ensuring their capacity to accurately replicate the present climate. When models can faithfully reproduce the current climate, confidence in their future projections is bolstered. Hence, this study assessed the capabilities and uncertainties of the Regional Eta Model, forced by three Earth System Climate Models (BESM, HadGEM2 ES, and MIROC5), as well as the capacity of the hydrological model MGB IPH forced by meteorological variables, after bias correction, and evaluated their representation of the hydroclimatology of the Madeira River basin. Subsequently, the impacts of increased greenhouse gas emissions and deforestation on precipitation, evapotranspiration, discharge, and floods were examined using the Eta Climate Model and the MGB Hydrological Model. The results reveal that the Eta climate model yields coherent simulations aligned with the climatological features of the Madeira River basin. However, substantial biases persist due to inadequate parameterization schemes, necessitating further investigation. While the MGB hydrological model successfully captures the primary features of the region, it exhibits certain limitations, particularly concerning distinct discharge regimes. Nevertheless, the model's overall performance was deemed satisfactory.Following the evaluation of both climatic and hydrological models, the impacts of climate change and deforestation on the Madeira River basin were assessed. The increase in greenhouse gas emissions will lead to reduced precipitation during wet and dry seasons. Climatic models suggest that the upstream basin will become wetter, whereas the downstream basin will become drier. Moreover, increased greenhouse gas emissions will also affect evapotranspiration, introducing uncertainties in the Amazon rainforest's response to these changes. The combined effect of escalated greenhouse gas emissions and deforestation will precipitate negative feedback for the Madeira River basin, resulting in reductions in precipitation, evapotranspiration, discharge, and floods. Increased greenhouse gas emissions will trigger alterations in precipitation and evapotranspiration patterns. In turn, deforestation will impact soil moisture and the forest's water absorption capacity, affecting the discharge and flood cycle. These findings are pivotal for water resource management and forecasting the ramifications for aquatic ecosystems and human communities reliant upon these resources.