1. Desertification
Introduction

2. What is Desertification?
Desertification can be defined as the diminution or destruction of the biological potential of the land, often resulting in ‘desert’- like conditions.
Many observers believe that desertification is caused by a combination of both physical and human factors.

3. What is Desertification?
Desertification is the loss of soil and its productivity in the arid and semi-arid regions of the world (defined as having less than 250 mm of rainfall per year) mainly due to its overuse by man.
By undermining food production and contributing to malnutrition and famine, desertification can have devastating consequences.

4. The extent of the problem:
20 million km2 of land are degraded every year and this affects over 280 million people (Table 1).
More than 110 countries have drylands potentially at risk from desertification, with the possibility of affecting 900 million people.
Those already suffering include Africa (both North and South), China, Pakistan, Australia and North America. Desertification does not differentiate between developing and developed countries.

7. The extent of the problem:
The problem does not just occur on the fringes of natural deserts, but in any dry area.
The United Nations claim that $45 billion will be needed every year for the next twenty years to reclaim degraded land.

8. The extent of the problem
The symptoms of desertification include soil erosion, loss or degradation of vegetation, desiccation of the soil profile, lowering of the water table, dune formation or reactivation and salinisation.

9. Drylands Drylands have growing season between 1 and 179 days.
Deserts and hyper-arid areas are not classified as drylands because they cannot support grain fed agriculture.
Agriculture relies on rain.
40% of the world is classified as drylands.

10. Drylands
Soil is being lost from agricultural regions at times faster than the rate of soil formation.
20 million km2 of land is being degraded annually.
110 countries contain drylands. Continents such as Africa, Asia and Australia already contain deserts.
Approximately 1/3 of all land on earth is threatened by desertification.

11. Drylands
Globally, 1.9 billion hectares of land is degraded, impacting upon 1.5 billion people.
$45 billion dollars are needed annually for the next 20 years to reclaim degraded land.
There is a strong spatial association between countries with large scale land degradation and low levels of economic development. Especially when livelihoods are directly linked to the land.
Each year 12 million hectares are changed in desert like environment annually. This land has the potential to produce 20 million tonnes of grain per year.