Climate change impacts on evapotranspiration in Brazil: a multi-model assessment

• Published in: Theoretical and applied climatology Vol. 155; no. 6; pp. 5363 - 5373
• Main Authors: Monteiro, Ana Flávia Martins, Torres, Roger Rodrigues, Martins, Fabrina Bolzan, Marrafon, Vitor Hugo de Almeida
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.06.2024; Springer Nature B.V
• Subjects: 21st century; Agricultural commodities; Air temperature; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Balances (scales); Climate; Climate change; Climate change scenarios; Climate models; Climatology; Earth and Environmental Science; Earth Sciences; Environmental impact; Estimation; Evapotranspiration; General circulation models; Humidity; Impact analysis; Intercomparison; Original Paper; Radiation; Radiative forcing; Regional analysis; Relative humidity; Solar radiation; Surface temperature; Surface-air temperature relationships; Uncertainty analysis; Waste Water Technology; Water balance; Water balance models; Water Management; Water Pollution Control; Brazil
• ISSN: 0177-798X; 1434-4483
• DOI: 10.1007/s00704-024-04942-6

A large part of Brazil is highly vulnerable to climate changes projected for the end of the 21st century. Analyzing these vulnerabilities is particularly important for agriculture, since the country is one of the largest agricultural commodity producers in the world. Changes in the reference evapotranspiration ( ET o ) can impact crops and make cultivation unfeasible. However, studies on ET o patterns under climate change scenarios for Brazil have been restricted to regional scales and use too few climate models or too simplified water balance models for their analysis. This can lead to uncertainties in assessing the impacts of climate change on ET o . Therefore, this study seeks to analyze ET o patterns in Brazil towards the end of the 21st century using two methods that are better at estimating regional ET o , i.e., the Turc and Abtew methods, under two radiative forcing scenarios (RCPs 4.5 and 8.5). Daily data on near-surface air temperature (mean and maximum), global solar radiation, and near-surface relative humidity from six General Circulation Models (GCMs) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were used to analyze the simulations and projections for climate change. The performance of climate simulations is heterogeneous among the GCMs, with overestimations (~ 2.5 mm day − 1 ) in some models, and underestimations (~ 1.5 mm day − 1 ) in others. In general, climate change projections indicate increases of up to 1 mm day − 1 in ET o , mainly in the North, Northeast, and Center-West regions of Brazil. Both estimation methods showed similar spatial patterns, however the Turc method projected lower intensity changes compared to the Abtew method. Highlights The  Turc  method showed the best performance in estimating ET o , resulting in more reliable climate simulation and projections. There was divergence between climate models when simulating solar radiation and relative humidity. Climate models projected an increase in temperature (mean and maximum), and a reduction in relative humidity towards the end of the 21st century. The projected ET o showed similar patterns between the Turc and Abtew methods. Increases from 0.4 to 1 mm day − 1 are projected for ET o in the North, Northeast, and Center-West of Brazil, and from 0.2 to 0.4 mm day − 1 in the South of Brazil.