The future of environmental sustainability in the Taita Hills, Kenya: assessing potential impacts of agricultural expansion and climate change

Abstract

The indigenous cloud forests in the Taita Hills have suffered substantial degradation for several centuries due to agricultural expansion. Currently, only 1% of the original forested area remains preserved. Furthermore, climate change imposes an imminent threat for local economy and environmental sustainability. In such circumstances, elaborating tools to conciliate socioeconomic growth and natural resources conservation is an enormous challenge. This article tackles essential aspects for understanding the ongoing agricultural activities in the Taita Hills and their potential environmental consequences in the future. Initially, an alternative method is proposed to reduce uncertainties and costs for estimating agricultural water demand. The main characteristic of the approach proposed in this study is the use of satellite data to overcome data availability limitations. Furthermore, a modelling framework was designed to delineate agricultural expansion projections and evaluate the future impacts of agriculture on soil erosion and irrigation water demand. The results indicate that if current trends persist, agricultural areas will occupy roughly 60% of the study area by 2030. Rainfall erosivity is likely to increase during April and November due to climate change and slight decrease during March and May. Although the simulations indicate that climate change will likely increase total annual rainfall volumes during the following decades, irrigation requirements will continue to increase due to agricultural expansion. By 2030, new cropland areas may cause an increase of approximately 40% in the annual volume of water necessary for irrigation.