World Day to Combat Desertification on June 17 :

Enhancing soil, improving life

By Pramod DE SILVA

Deserts are among the most well-known geographical features on Earth. Even a fifth-grader will rattle off the names of most of the world's famous deserts. We know what deserts are: barren, hot, arid, vast sandy landscapes with no vegetation in sight. Life does exist on these scorched lands, but barely so.

One may think that the world's deserts are static. But the truth is that they are expanding. Other lands are turning into deserts at an alarming rate in a process called desertification. In other words, the world risks losing its forest cover and fertile soils.

This issue will be highlighted on the World Day to Combat Desertification and Drought, on June 17. The UN Convention to Combat Desertification (UNCCD) has decided on the theme for this year as "Enhancing soils anywhere enhances life everywhere". The UNCCD is the only internationally recognised, legally binding instrument that addresses the problem of land degradation in the drylands and which enjoys a universal membership of 191 country parties.

The year 2010 is the International Year dedicated to Biodiversity. To this end, UNCCD aims to sensitize the public to the fact that desertification, land degradation and drought dramatically affect the biodiversity resident in the soil.

Explaining the theme, the UNCCD says: "There is a close relationship between livelihood and ecosystem wellbeing, and soils that are rich in biodiversity. Healthy soils produce life, and yet soil health depends a lot on how individuals use their land.

What we do to our soils determines the quality and quantity of the food we eat and how our ecosystems serve us. Our increasing ecological interdependence also means enhancing soils anywhere enhances life everywhere."

There's an urgent need to curb the destructive forces of desertification, land degradation and drought. This year marks the beginning of the UN's Decade for Deserts and the Fight Against Desertification, so this year the day has special significance.

Scientifically, desertification refers to the formation and expansion of degraded soil. In simple words, it means the decline in the biological or economic productivity of the soil in arid (annual rainfall less than 600 mm) and semi-arid areas resulting from various factors, including human activities and climatic variations.

Desertification reduces the ability of the land to support life, affecting wild species, domestic animals, agricultural crops and people. The reduction in plant cover that accompanies desertification leads to accelerated soil erosion by wind and water. Desertification is self-reinforcing - once the process has started, conditions are set for continual deterioration.

The special day has gained significance all over the world as there is an urgent need to control desertification and to strengthen the visibility of this issue on the international environmental agenda.

The World Day to Combat Desertification and Drought was declared by the UN General Assembly in 1994 to mark the anniversary of the UNCCD, which plays a key role in the fight against deserts and desertification. The main objectives are to remind everyone that desertification can be tackled, that solutions are possible and that the key tools to solve it lie in strengthened community participation and co-operation. The event is celebrated all over the world to highlight the urgent need to curb the process of desertification.

The event is a reminder that drought and desertification can be tackled effectively and that solutions are possible, if only the key tools to achieve these goals - strengthened community participation and co-operation at all levels - are forthcoming. It was just four years ago (2006) that the world marked the International Year of Deserts and Desertification when the need for such action was stressed by world leaders.

Desertification and land degradation have affected one-third of the earth's surface; threatening the livelihoods, well-being and development of as many as one billion people. Nearly one-third of world cropland has become unproductive and has been abandoned during last 40 years.

Desertification is most widely seen in Africa. Africa's arid zones have been getting progressively drier over the past 5,000 years. What's new is the pressure put on by the increasing number of people and livestock. Areas north of the Equator are suffering seriously with deserts in the semi-arid areas of West Africa expanding at an annual rate of five kilometres. Forty six per cent of Africa is affected by desertification, with 35 per cent of this area being at high risk. It affects over 485 million people living along desert margins.

The world's great deserts were formed by natural processes interacting over long periods of time. In some regions, deserts are separated sharply from the surrounding, less arid areas by mountains and other contrasting land forms that reflect the basic structural differences in regional geology.

In other areas, desert fringes form a gradual transition from a dry to a more humid environment, making it more difficult to define the desert border.

Desertification occurs in croplands, pastures and woodlands. Loss of soil, deterioration of soil and loss of natural vegetation all lead to desertification. Drought can cause loss of vegetation, which in turn leads to desertification.

Poor land management and increasing populations promote increased irrigation, improper cultivation or over-cultivation and increased numbers of livestock. These increase chances of desertification.

Desertification is complex. It involves multiple causes and proceeds at varying rates in different climates. Desertification may intensify a general climatic trend and lead to no rain at all or it may change the local climate.

Areas far from natural deserts can degrade quickly to barren soil, rock or sand through poor land management. The presence of a nearby desert has no direct relationship to desertification. Unfortunately, areas undergoing desertification are brought to public attention only after the process is well underway. Scientists still question whether desertification, as a process of global change, is permanent or how and when it can be halted or reversed.

Increased population and livestock are the main contributors towards desertification.

In some areas, nomads moving to less arid areas disrupt the local ecosystem and increase the rate of erosion of the land. Nomads try to escape the desert, but because of their land-use practices, they are bringing the desert with them.

Other factors including poverty, politics, disrupted social institutions and the pursuit of short-term economic opportunities may work together to promote desertification.

The provision of water for irrigation can cause desertification. Nearly all irrigation water contains some salt. If an irrigation system lacks a good drainage system, then salt accumulates in the soil. This has now destroyed about one-third of the world's irrigated land.

In most cases of desertification, there is a reduction in total species richness, an increase in the proportion of exotic plants and a decline in overall bio-diversity.

Once desertification has started, it often causes changes that accelerate the process.

Desertification has become a large scale problem. Arid and semi-arid regions, known as dry lands, account for one-third of the world's land area and support a combined population of about 900 million people. Soil degradation reduces crop output and is a major concern economically.

Most efforts to combat desertification require temporary reductions in economic productivity or increases in investment. Experts recommend decreasing herd sizes, changing ploughing practices, planting windbreaks, planting less profitable crops which do not rob the soil of nutrients and allowing each field to lie fallow on a rotating basis. In irrigated agriculture, more expensive and intensive water management is recommended, requiring improved water delivery systems, field preparations and drainage systems.

This is not a phenomena that we in Sri Lanka can afford to ignore. The vagaries of climate change, the dwindling of the forest cover, soil erosion, destructive agri practices and several other factors are affecting our fertile soil.

We must act to stop these trends before desertification becomes a reality here as well.

June 17 should give us a good start.