Terrestrial evapotranspiration is a crucial process for the environment, but it's hard to measure accurately. Scientists have developed a new model that uses solar-induced chlorophyll fluorescence to estimate how much water plants release through their leaves. By combining this fluorescence with vapor pressure deficit, they were able to predict plant water loss more accurately than before. The model was tested in forests and croplands, showing promising results in predicting water loss at different time scales. This new approach could help us better understand how carbon and water cycles are connected and improve estimates of water loss in large areas.