Introduction

One third of the world’s population lives in areas with water shortages and 1.1 billion people lack access to safe drinking water. Globally, drought (7.5%) is the second-most geographically extensive hazard after floods (11%) of the earth’s land area. The percentage of area affected by serious drought has doubled from the 1970s to the early 2000. Europe and Asia, Canada, Western and Southern Africa. and Eastern Australia experienced widespread drought. Mega-droughts hit the Yucatán Peninsula and Petén Basin areas with particular ferocity, because of thin tropical soils, which decline in fertility and become unworkable when deprived of forest cover; regular seas onal drought, drying up surface water; the absence of ground water; the rarity of lakes, especially in the Yucatán Peninsula; the absence of river systems, such as in the Petén Basin; tropical vegetation which requires regular monsoon rain, and heavy dependence upon water-based intensive agricultural techniques, particularly in the Classic period. Rising global temperatures appear to be a major factor provoking more frequent and intense droughts in sub-tropical areas of Asia and Africa. It is reported that the Northern Hemisphere has recorded an increase of 1°C in the past 1000 years and the fluctuation is quite rapid during 1850 and 2000 and the upward trend still persists. The climate models predict a global warming of about 1.4°C–5.8°C between 1990 and 2100 and the sea level to rise by 9 to 88 cm. With increase in global temperatures the world is likely to experience more hot days and heat waves and fewer frost days and cold spells.