Silicon is one of the most abundant elements on Earth and plays an important role in maintaining high water quality in lakes and rivers. Scientists used to think that silicon levels in rivers stayed fairly consistent, even when water flow changed a lot. But new research shows that changes in climate and land use, like temperature shifts and agricultural development, may be affecting how much silicon rivers carry. To investigate this, we studied over 20 years of data from 467 rivers across all seven continents. We used machine learning models to figure out which environmental factors best explain how silicon levels in rivers change with water flow. We found silicon levels in most rivers either increased or decreased with changing water flow, in contrast with our previous understanding. Key factors included temperature, vegetation growth, snow cover, the size of the watershed, and the amount of farmland. This study helps fill a critical gap in our understanding of how rivers transport silicon, especially as climate and land use changes continue globally. Knowing how and why silicon levels shift can help scientists and water managers make better predictions about water quality and ecosystem health in the future.