ABSTRACT
The tropics1 is home to 40% of the world’s population, the highest levels of population growth, and the majority of the world’s poor. It is also where most of the sun’s energy that drives global climate is absorbed and, as such, where changes in the water-holding capacity of the atmosphere as a result of anthropogenic warming are highest (Allen and Ingram 2002; Trenberth et al. 2003). Consequently, it is in the tropics where the impacts of rapid development and climate change on water resources are expected to be the most severe and where the need for sustainable adaptive management strategies in the water sector is greatest. Perversely, it is the tropics where the human and institutional capacity
and hydrological knowledge base to devise adaptive water strategies are the most limited. Groundwater has for decades enabled communities across the tropics to adapt to seasonal or perennial shortages in surface water by providing water for drinking, watering livestock, and more recently irrigation. It is unclear, however, whether more intensive groundwater abstraction to meet rapidly rising demand for domestic and agricultural water is viable. Furthermore, a quantitative understanding of the impact of climate change on groundwater resources in the tropics remains elusive.
