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Facts
- The 'World Day to Combat Desertification and Drought'
is 17 June.
- Nearly one-third of the earth is classed as arid or semi-arid
desert.
- An estimated six million hectares of productive land are lost
every year because of desertification, land degradation and declining agricultural
productivity.
- More than 110 countries are affected by desertification.
- Over
250 million people are directly affected by desertification and one billion people
are at risk. These people include many of the world's poorest, most marginalised,
and politically weak citizens.
- The African continent is most affected
by desertification. Two-thirds of the continent is desert or drylands, almost
three-quarters of which are degraded to some degree.
- Roughly 27 per cent
of the China's land mass is desertified, with an average of 2,460 square kilometres
of land being lost to advancing deserts each year. Nearly 400 million people live
in these areas, and the economic loss to China has been estimated at around US$6.5
billion a year.
- It is estimated that US$42 billion is lost worldwide each
year through desertification.
Source:
United Nations Convention to Combat Desertification
http://www.unccd.int/
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BackgroundWhat
are deserts?Deserts are very dry places. They receive very low rainfall
and in hot areas evaporation causes high water loss. There are many types of deserts
with a variety of climates (hot, cold), locations (inland, coastal), appearance
(sandy, rocky), and levels of vegetation (none, low ground cover, shrubby bushes).
Hot deserts, located near the equator, have hot days and cold nights because of
the lack of the protective cloud cover. Cold deserts, away from the equator and
usually in the centre of continents in high mountainous areas, have winters of
ice and snow. Flora, fauna and people who live in deserts have adapted
in many ways to the dry environment. Plants may have deep roots systems to access
the water table, water storing leaves, tiny leaves to limit water loss, or are
able to respond rapidly to rain. Animals have adapted to life in the desert in
three major ways: expiring (short life cycles and laying eggs which survive until
next rains), evading (migrating out of the area during extreme dry) or enduring
(limiting water loss). Traditional desert dwelling people move around during the
year to access the water and food sources without overusing them. In addition
to their dependence on the land, many desert people also have a strong spiritual
connection to landforms and flora and fauna. Increasing population and
environmental changes are altering life in the desert. New technologies improve
access to water and food, but may lead to overuse; higher quality of life expectations
mean people may be drawn to towns; governments may encourage people to settle
in one place to make the delivery of services easier; and land degradation may
make it impossible to survive in the traditional manner. Deserts now are
used for many purposes. Their spectacular scenery is a source of tourist revenue,
their mineral content is mined, and their isolation means they may be used as
testing grounds for weapons or dumping places. The increasing demands put pressure
on the fragile desert and semi-desert areas, leading to desertification. What
is desertification?Desertification refers to both the spreading of
current deserts and the degradation of land in areas of low rainfall. It is caused
by both natural factors, such as drought, and human factors, such as overuse.
A climate with large daily temperature variations, strong winds and intermittent
but intense rainfall makes the fragile soils vulnerable to erosion and desertification.
Increasing human demands lead to desertification through overcultivation,
overgrazing, deforestation and poor water management. Grazing animals and firewood
collection damage the vegetation holding soils together. Soil compacted by hard-footed
animals is less able to soak up rain when it does fall and is easily eroded by
the water and wind. Cutting trees for firewood leaves soil unshaded, leading to
an increase in the temperature of the soil and in the rate of evaporation which
draws salts to the surface. This further reduces plant growth. The high demands
for the limited surface and ground water reserves leads to overuse and further
salination. What are the consequences of desertification?The
loss of soil fertility and vegetation cover and the decline of groundwater, which
characterise desertification, lead to loss of biodiversity and productivity. This
contributes to social, economic and political tensions. Lower yields from crops
or grazing animals may lead to famine, poverty and conflict, forcing people to
move away from their local area and lose their connection to the land and cultural
traditions. Relocation can put pressure on other fragile environments and cause
conflict and further relocation. Even people living further away are affected,
as sandstorms cause respiratory problems and skin disorders. The blowing sand
decreases visibility in cities and clogs rivers and water catchments. Desertification
is both a cause and a consequence of poverty. Poorer and marginalised people are
forced to farm fragile land, and seeking to make a living from it may cause further
degradation. Combating desertificationPractices to rehabilitate
degraded land and limit desertification include making use of traditional knowledge,
prioritising food security over cash cropping, promoting alternative income sources,
reforestation, implementing land management strategies (ridging, development of
catchment basins, contour bunding and terracing), and water management (efficient
use of existing water resources, control of salination and drip irrigation). It is only recently that scientists have been able to gauge the extent of desertification before it was well advanced. Satellite imaging helps monitor changes and prompt earlier preventative measures. Methods of combating desertification include planting seeds of new crops into the straw of previous crops to limit ploughing and soil disturbance, new crop rotations, appropriate animal numbers, planting sand-fixing plants and tree belts, and the development of renewable energies for heating and cooking.
Australia's
responseAustralia's experience in tackling land degradation has been important
in helping other countries address their resource management problems. The Australian
Government, through the Australian Agency for International Development (AusAID),
is currently supporting a range of bilateral programs to combat desertification
in developing countries. Through the Australian Centre for International Agricultural
Research (ACIAR), the Australian Government funds collaborative agricultural research
projects in China, India, southern Africa and Southeast Asia. Source:
Australian Actions to Combat Desertification and Land Degradation
http://www.deh.gov.au/land/publications/actions/
The
global agenda The United Nations Convention to Combat Desertification (UNCCD), the United Nations Framework Convention on Climate Change (UNFCCC), and the Convention for Bio Diversity (CBD) were all signed at the Rio Earth Summit in 1992.
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