A warming climate increases tropical cyclone intensity, causing more intense rainfall. This creates problems for soil and water conservation and management, particularly for countries in the western tropical-subtropical Pacific region, where cyclones (typhoons) frequently occur. Taiwan is located on a typhoon track and frequently suffers from devastating floods and landslides generated by typhoons. Here we present qualitative and quantitative evidence from Taiwan for the changing characteristics of rainfall-runoff patterns and the associated geomorphic response under a changing climate. We speculate regarding the impact of global warming on the hydrological cycle and associated processes and the threats posed to the inhabitants of the mountainous island of Taiwan.