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It is hard to define drought because it has a different meaning in different areas of the world. As you know there are climates with variable characteristics all around the world, and, as you can imagine drought does not mean the same for all of them. In a very arid region there has to be a really long period with no precipitation to be considered as a drought, on the other hand, in tropical areas for example, a period of six days with no rain at all, can be already considered as a drought event.
Drought definition, then, depends on the place on Earth were we are, but, is that enough? Not really, drought definition also depends on the demand that people place on water, if there are such people. Think about it, if there is a period of reduced rainfall, but there is no one around using water…can we say this is really a drought? It is, because precipitation has been reduced from the normal amount, but no one has been affected by this reduction. On the other hand, there might be a reduction in rainfall in a very populated area where agriculture is covering a big extension…of course we would say there is a drought here, and consequences would be harder in this case than in the first one as there is a need of water for human needs and for watering plants
Whatever the definition, it is clear that drought cannot be viewed solely as a physical phenomenon since it depends on how much water is needed by society. Drought impacts on society result from the relation between the natural event of decrease of precipitation and the demand people place on water supply. The presence of human beings often exacerbates the impact of drought. Recent droughts have underscored the vulnerability of all societies to this “natural” hazard.
According to this we can understand why there are parts of the world, which are more vulnerable to droughts (depending on climate, type of agriculture, water management…)
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