Regional Impact of Climate Change on Water Resources over Eastern Mediterranean: Euphrates-Tigris Basin

Significance of water resources management is much greater in the case of the developing countries than in the developed ones. Over the Eastern Mediterranean region several studies have been conducted on water resources and its importance but none of them has focused on the role of future climate change. Trans-boundary streamflows (Euphrates-Tigris) are the main sources of the water for the region, not only for domestic and industrial usage, but also for energy.

It is obvious that 1990's were the warmest period over Europe in the last century. In contrast, during the same period significant cooling has been observed over Eastern Turkey which includes the Euphrates-Tigris basin. It is very important to observe that CRU (Climate Research Unit) data set shows a cooling pattern over this area even if the temperature increased all around Europe during the last decade. This cooling behavior over the region of interest has been observed in both CRU data and station data. During the last 30 years over Euphrates-Tigris, several dams and irrigation systems have been constructed and resulted in major land use changes.

To understand present and future climate changes over the Euphrates-Tigris basin, we have focused on the precipitation component of the regional hydrological cycle. The regional climate model (RegCM3) has been used to downscale the regional climate simulations of the Finite Volume GCM (1^°x1.25^°). Based on IPCC GHG forcing and present conditions, climate change over the region of interest has been investigated.

Our primary finding is that the climate anomalies associated with the projected regional global warming tend to manifest themselves in terms of multi-decadal variability North Atlantic Oscillation. More specifically, there is dramatic precipitation increase (approximately 20%) over the northern part of domain of interest (Black Sea). In contrast, the southern part of the domain of interest exhibits the apposite anomaly conditions. We hypothesize that these changes in precipitation could have very significant implications regarding the total hydrological cycle over the region.