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Food & Climate
1. Plants and climate
2. The climate change issue
3. Drought in the Mediterranean
- what is drought?
- causes & types of drought
- drought and fire
* Worksheet 1
* Worksheet 2
* Worksheet 3

Food & Climate 


What is Drought?

Drought is really a normal feature of climate that happens nearly every year in many areas of the world even if it is hard to believe.




It is important to make a difference between aridity and drought, being the first one the permanent state of low rainfall in certain areas on Earth (a desert is a very arid region), while Drought is a temporary event (there can be a drought in the Amazons, but this is not an arid region).


1. comparison between an arid zone (left) and a humid zone suffering from drought (right)
Pictures by Ana Iglesias

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…)


Drought in the Mediterranean

Drought is a severe problem in the Mediterranean as we just said in the introduction to this Unit. this area holds one of the highest rates of population growth in the world and, is considered many times (in International conventions and Institutions like  the World Bank and the International Water Forum), as a case of special attention due to the problems stemmed from the vulnerability to drought and water managemant.

Although countries in the Mediterranean region are very different from one another, a common solution to all of them would be to improve the use of water in agriculture, which is the most important economic activity in these countries. Many solutions are being studied, from the use of groundwater resources in times of drought, the construction of surface reservoirs for water to economical solutions like rising the price of water or creating "water markets"so that great users of water can try to save water in their use in order to be able to sell it to other users that might need it.


Author:  Marta Moneo and Ana Iglesias- Universidad Politécnica de Madrid - España
1. Scientific reviewer: Alex de Sherbinin - CIESIN, Columbia University - USA
2. Scientific reviewer: Lily Parshall - Goddard Institute for space studies, Columbia University - USA
Educational reviewer: Emilio Sternfeld - Colegio Virgen de Mirasierra - España
Last update: 12/05/2004



last updated 11.07.2005 10:51:30 | © ESPERE-ENC 2003 - 2013