Climate Change Impacts on Green Water Fluxes in the Eastern Mediterranean

Abstract

The present paper is part of the Glowa Jordan River project, which has been focusing on climate change impacts on environmental, economic and social issues within the lower Jordan river riparian states. The eastern Mediterranean is characterized by scarce and erratic precipitation with relatively cool, wet winters and dry hot summers. Water is the biggest growth-limiting factor. The present paper discusses the use of climate gradient as a tool to examine the impact of climate change on precipitation partitioning over field crops. The present experiment is carried out using a multi-layer, multi-year model with a daily time step. Six years of daily data for five locations, with average annual precipitation ranging from 170 to 580 mm, were used in this investigation. Results show that the ratio of soil evaporation (BE) to annual precipitation (P) during the growing season depends strongly on precipitation regime and amount, ranging from ~15 to 20% when P > 600 mm to ~60% when annual P < 200 mm. A decrease of 10% in precipitation along with a temperature rise of 2°C increases bare surface evaporation, on average, by ~10% compared to average current conditions. The implications of this would be a tangible reduction in blue and green water fluxes, leading to compulsory land use shift and further water stress in the region.