Analysis of the Causes and Consequences of Drought in South Khorasan Province and Birjand

Climate change is one of the biggest challenges in the present century. Natural forces resulting from climate change, such as droughts, storms, heavy floods, temperature rise, untimely chill, rise in sea levels, increasing plant pests and diseases, and deforestation, have caused irreparable damages to earth. Drought is a slow but growing and complicated phenomenon caused by shortage of rain and rise in temperature. Unlike other natural phenomena, it is difficult to anticipate its beginning, duration and end. South Khorasan Province has been experiencing drought since 1998. The present study aims initially to analyze the meteorological data in order to determine the time and length of drought, identify places with high risk of drought according to Standard Precipitation Index (SPI), rating percentage index and decile indices and statistical features of monthly precipitation of synoptic weather stations in South Khorasan and Birjand from 1989 to 2016, and then tries to analyze the reasons and socio-economic and bioenvironmental consequences of drought in order to propose plausible solutions. The findings show that the most severe period of drought was from 1999 to 2001. Moreover, this province had the highest amount of precipitation from 1990 to 1991 and since 1998 the precipitation has been near normal or drought in this province. Among the cities of this province, Qaen, Khusf, Boshrooyeh, Tabas and Ferdows have suffered the most severe droughts, respectively.