Groundwater flow is crucial for Earth's systems, but many climate models don't consider lateral flow. A new model was created to include this process, using data from 67 stations in 10 countries and 1.6 million measurements worldwide. The study found that lateral groundwater flow affects water table patterns in North Africa, the Arabian Peninsula, central Asia, and southern Australia, deepening water tables by over 6 meters. Between 1970 and 2010, groundwater tables deepened by 0.025 to 0.125 meters per decade, with lateral flow making this trend worse. However, seasonal variations in groundwater levels were reduced by lateral flow's buffering effect.