Climate Encyclopaedia ESPERE.
ENVIRONMENTAL SCIENCE PUBLISHED FOR EVERYBODY ROUND THE EARTH
ENCYKLOPEDIA ESPERE - main menu (expand)
Topic: Food and Climate. Basics.
topic FOOD AND CLIMATE: BASICS - menu (expand)



What is Drought?

Drought is a normal feature of our climate.  Droughts happen nearly every year in many areas of the world.

It is important to differentiate between aridity and drought.  Arid areas, such as the deserts, have permanently low rainfall amounts, while droughts are temporary dry periods.  It's possible to have a drought event in the Amazon Rain Forest and this certainly isn't an arid area!

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

It is hard to define drought because it means something different in different areas of the world.  In a very arid region there has to be a really long period without rain for it to be considered a drought event.  However, in tropical areas six days without rain is a period of drought. 

The definition of drought, therefore, depends on the place on Earth where we are.  Is this definition good enough?  Not really!  The definition of drought also depends on the demand that people living in the area place on the water resources.  This, of course, depends on the number of people living in the region.  Think about it.  If there is a period of reduced rainfall, but nobody lives in the area, can we really say this is a drought?  It is, because rainfall amounts are less than normal but no one has been affected by the reduction.  On the other hand, there might be a reduction in rainfall in a very populated area where local agriculture is a very important food source.  We would, of course, consider this a drought and the consequences of this would be large both because water is needed for human life and for animals and crops.

Whatever the definition, it is clear that drought cannot be viewed solely as a physical phenomenon since it's impact depends on how much water is needed by society.  The presence of humans often exacerbates the impact of drought.  Recent droughts have brought home the vulnerability of all societies to this “natural” hazard.   How vulnerable a part of the world is to drought depends on it's climate, it's type of agriculture, how developed it is and how it manages it's water resources.

Drought in the Mediterranean

Drought is a severe problem in the Mediterranean.  International conventions and Institutions such as the World Bank and the International Water Forum all consider the area in need of special attention due to problems resulting from its vulnerability to drought and its requirements for better water management.

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 possible solutions are being studied, the use of groundwater resources in times of drought, the construction of surface water reservoirs and economical solutions.  These include increasing the price of water or creating "water markets" so that large water users can sell unused water credits.

About this page:
author: Marta Moneo and Dr. 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 published: 2004-05-12

Ostatnia modyfikacja: piątek, 17 maj 2019, 12:59