BBC: As global temperatures rise, more rain will fall than snow, and that change in precipitation can reduce the amount of water flowing in rivers, according to a recent study. Ross Woods of Bristol University in the UK and his colleagues base their findings on data gathered between 1948 and 2001 from 420 catchment basins in the US. When they compared places with similar climate and precipitation, they found that more precipitation made it into waterways in snowy regions than in rainy ones. One reason they propose is that in snowy regions the ground is frozen, so more water flows directly into the rivers. In rainy areas, more precipitation is absorbed by the ground. The finding could be significant for people who depend on local waterways for their water supply. However, the issue may be further complicated by other aspects of climate change, which could affect overall precipitation by causing more droughts and floods.