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When Green Earth Turns Into Sand


Its natural treasures include fabled Mt. Kilimanjaro, the highest peak in Africa. Lake Victoria, one of the continent's most celebrated bodies of water, laps its northern border and touches on the wildlife-rich Serengeti Plain. But according to experts at home and abroad, much of Tanzania - a green jewel of Africa - is facing an ecological disaster of stunning proportions.


Eye in the Sky


It is becoming a desert.

Government officials in Dar es Salaam recently declared that the rate of desertification in the country has surpassed efforts to contain it. The chief culprits: drought and deforestation. With more than 998,000 acres (400,000 hectares) of forests being razed every year, researchers estimate that half the country will be covered by sand within the next 50 years.

"Adverse weather changes and increased human activities" are to blame, according to senior government environmental official Richard Muyungi. He says that a problem once confined to dry lands in the central part of the country has now expanded to some coastal areas and to the Usangu rift valley - the principal source of water in the country's southern highlands.

Tanzania has suffered four years of drought, possibly aggravated by deforestation of coastal areas. Also blamed are a broad range of agriculture-related depredations such as over-grazing, soil exhaustion and excessive irrigation.

All of these activities have been exacerbated by the needs of hundreds of thousands of refugees who have fled political unrest in other African countries.

WORLDS OF SAND

Desertification is a growing problem not just in Africa, but also in Asia, Latin America, the Caribbean, and the northern Mediterranean. At a United Nations conference held in Bonn December 11-20, German President Johannes Rau estimated that one-quarter of the Earth's surface is threatened by conversion to desert.

"Desertification makes for poverty, and poverty makes for desertification," Rau told some 2,000 conference delegates representing more than 170 countries at the Fourth Session of the Conference of Parties to the United Nations Convention to Combat Desertification. "We [the world] are still living beyond our ecological means, and that will sooner or later spell trouble for the economy too."

Rau estimated that 14.8 million acres (6 million hectares) of productive land has been lost every year since 1990 due to land degradation. He said that 12 million people die annually because of resulting inadequate supplies of safe drinking water.

Africa has been especially hard hit. Nigerian Minister of Environment Alhaji Sani Zango Daura in August warned that the rapid expansion in desertification in the northern part of that country is affecting food production. He estimated that sand is marching south at a half-mile (0.6 kilometers) a year, and complained that "a larger percentage of our productive agricultural lands is impoverished and has resulted in poor agricultural yield, and the consequent food scarcity in the country."

Yet the pressure to clear forests continues. In addition to cooking and heating, wood provides fuel for many of Africa's small industries, such as brick-making and tobacco curing. Typically, fuel is cut from the natural woodland nearest a village, with the result that forests in close proximity to many settlements have disappeared. In some areas villagers replant quick-growing eucalyptus trees, but land rights issues often frustrate these efforts.

A group of environmentalists and university researchers in early December expressed alarm over desertification in Kenya and called for urgent measures to counter the process. University of Nairobi Vice-chancellor Francis Gichaga declared that the country - along with the rest of Africa - faces "a crisis of sustainability."

In another signal of Africa's growing awareness of the threat, all African countries have now joined the UN's desertification convention, which has been signed or acceded to by 169 countries worldwide. The convention commits countries to combating desertification at national, sub-regional and regional levels by enacting laws requiring environmental protection and sustainable development.

TEXTBOOK CASE

Unfortunately, such steps will come too late for areas already claimed by desert sands or in imminent peril of becoming so. Unlike many natural phenomena, the effects of desertification usually cannot be reversed within a single lifetime. Scientists define desertification as the conversion of arid or semiarid regions to desert due to climatic changes, human activities or both. Drought often sets the stage. Removal of trees and other vegetation deprives the land of its ability to retain water, leading to excessive erosion and exhaustion of surface-water and groundwater. Poor cultivation techniques often exhaust the soil of newly cleared land within a few planting seasons, resulting in the need to clear more forest.

Tanzania has proved a textbook case. Wood is by far the country's most important source of energy, accounting for more than 90 percent of the national energy supply. At the same time, farmers often resort to burning large tracts of forest to clear land for crops. In 1994, the influx of hundreds of thousands of refugees fleeing fighting in Rwanda added pressure on Tanzania's already stressed natural resources. Many still remain in the country despite efforts by the Rwanda government to encourage them to return.

Earlier this year the Journalists Environmental Association of Tanzania reported "horrendous environmental destruction" in the Usangu rift valley wetlands due to intensive rice farming, overgrazing, and deforestation. The group declared that some rivers have dried up. According to Lake Manyara National Park ecologist Frank Silkwasha, several species of birds, animals and even trees are no longer seen in the area.

Locally extinct animals include eland, kudu, oryx and the wild dog. Birds threatened with extinction in the park include saddle-billed stor, fish eagle, long-tailed cormorant, shoebell, egrete and crowned crane.

Tanzania's ecological crisis has gotten the attention of the government of President Benjamin Mkapa, who launched a national tree-planting campaign in April. Mkapa has now decreed Jan. 1 as a "National Tree Planting Day." Tanzanians across the country are being asked to plant trees, hoping to slow down the march of the sands.

Eye in the Sky is a weekly series that brings you the story behind the headlines using satellite imagery, remote sensing, aerial photography, and maps. This feature is developed by National Geographic News with the sponsorship of the National Imagery and Mapping Agency (NIMA) and Earth-Info. Check out maps and imagery at http://www.earth-info.org.



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More Information
• Covering 364,879 square miles (945,090 square kilometers), Tanzania is more than twice the size of California.
• Tanzania's population of 31.2 million is increasing at an average rate of 2.36% per year.
• Wood accounts for 90 percent of Tanzania's total energy supply.


More Information
SOMALI'S BLACK GOLD

Desertification has become a matter of special concern among countries in the Horn of Africa such as Somalia, where the unregulated manufacture of charcoal has become a big business.

With no central government over the past decade, Somalia has had no restrictions on the clearing of its forests. Now the UN reports that vast areas of the country's bush have been stripped to feed an enormous appetite for charcoal in Saudi Arabia and the Gulf States - which have enacted regulations to prevent desertification in their own countries.

Most Somali households use charcoal for cooking. It is made by cutting down trees and burning closely stacked piles of branches and trunks, covering them with dirt to slow the process.

As entrepreneurs have discovered the demand for charcoal in the Arab states, the industry has mushroomed. Cutting has been taken up by major Somali clans wielding power chainsaws. The financial incentives are huge: A bag that costs about US $3 sells for about $10 in the Gulf states, according to a trader interviewed by UN officials. He reported that a ship typically takes as many as 100,000 bags, which can be made in about two months.

"There is no documentation of the volumes being exported or the amount of trees being cut down," says Somali agronomist Abdulkadir Shirwa. "I don't think anyone yet grasps just how bad the damage has been."