The researchers studied how regional climate models improve predictions compared to global models by looking at present climate biases and future projections. They used two regional models and two global models, comparing them for the U.S. and Mexico under multiple scenarios. Results show that the regional models reduce present biases in the global models, making future climate predictions more accurate. The differences between models in simulating current and future climates are lessened by the regional models. However, biases from the present still affect future climate projections, with some regions being more impacted than others. The study indicates that using regional models alongside global ones not only helps in representing current climate better but also enhances the credibility of future climate predictions.