Possible impacts of climate variability and change on tropical forest hydrology

The paper initially outlines selected uncertainties influencing climate change and their linkages with hydrology which have led to only a small section of the hydrological community (divided into 2 groups) being pro-active. Due to the foregoing uncertainties, the strategy adopted in this paper will be to focus on the principal conclusions from controlled experimental catchment studies and related process hydrology connected with land-use change arising from anthropogenic influences. The underlying philosophy is that even major natural disruptions to climate cause ecohydrological shifts in the response of landscapes and such changes may be indicated from recent hydrology research evaluating man-made impacts. The paper assesses the existing conclusions from hydrological work undertaken in both the closed forests of the humid tropics and the open forests of the tropical semi-arid regions based mostly from experimentation in headwater catchments. Such studies are concerned with the hydrological responses to the impacts of forest conversion on the change in total water yield and, in turn, the processes connected with dry weather flow (delayed flow) and storm runoff (quickflow). By taking the above approach, possible hydrological changes to climate change will be inferred, including some consideration given the outputs from atmospheric General Circulation Models (GCMs) using the Amazon basin as an example.