RAINFALL TRENDS AS AN INDICATION TO CLIMATE CHANGE SINCE THE 19TH CENTURY IN THE PALESTINIAN CENTRAL MOUNTAINS: JERUSALEM GOVERNORATE AS A CASE STUDY

Abstract

Climate change is a worldwide problem that is facing the globe in different aspects. To investigate this phenomenon, research has been conducted to check whether climate change is affecting the western part of Jerusalem Governorate or not. Long-term data on annual, seasonal and monthly rainfall were collected from different sources and analyzed for long-term monthly and annual trends. Results showed significant (p< 0.05) decrease in the annual rainfall, with about 7.3 mm decadal reduction during 1850-2018. The highest and significant decrease in decadal rainfall occurred during 1890-1939 and 1980-2018, with a decadal decrease of 50.9 mm and 55.9 mm, respectively. The decrease corresponds to 84 mm reduction in annual rainfall since 1850, which could be attributed to the extended effect of the GHG from the industrial revolution on Palestine since the beginning of the 20th century. A significant and increasing trend in drought periods was also obvious, with 1.7 years of drought/ decade and an increasing drought recurrence during 1920-1930 and 1998-2018 periods (69% of the drought years occurred in the two periods). Winter season showed highest and significant reduction in rainfall than spring season (1.7 mm/decade and 0.7 mm/decade, respectively), whereas autumn season showed a non-significant decadal decrease in rainfall of about 0.04 mm/decade. The reduction in rainfall and the recurrence of more drought periods, especially the last 20 years, might be the cause for the concurrent reduction in rainfed agricultural areas in Palestine; about 38% reduction in the total rainfed areas (1515 km2 in 2000 to 929 km2 in 2017/2018).