Hydrological processes in the humid tropics differ from other regions in having greater energy inputs and faster rates of change. In this Review it is argued that understanding of the key hydrological interactions there remains limited, and a vision of future research designed to address these shortcomings is outlined.

Hydrological processes in the humid tropics differ from other regions in having greater energy inputs and faster rates of change, including human-induced change. Human influences on population growth, land use and climate change will profoundly influence tropical hydrology, yet understanding of key hydrological interactions is limited. We propose that efforts to collect tropical data should explicitly emphasize characterizing moisture and energy fluxes from below the ground surface into the atmosphere.