Desertification is the degradation of land in any dryland. It is caused by a variety of factors, such as climate change and human activities. Desertification is one of the most significant global environmental problems.
Considerable controversy exists over the proper definition of the term "desertification" for which Helmut Geist (2005) has identified more than 100 formal definitions. The most widely accepted of these is that of the Princeton University Dictionary which defines it as "the process of fertile land transforming into desert typically as a result of deforestation, drought or improper/inappropriate agriculture"
The earliest known discussion of the topic arose soon after the French colonization of West Africa, when the Comité d'Etudes commissioned a study on desséchement progressif to explore the prehistoric expansion of the Sahara Desert.
The world's great deserts have been formed by natural processes interacting over long intervals of time. During most of these times, deserts have grown and shrunk independent of human activities. Paleodeserts are large sand seas now inactive because they are stabilized by vegetation, some extending beyond the present margins of core deserts, such as the Sahara, the largest hot desert.
(Clifford) Allan Redin Savory (born September 15, 1935) is a Zimbabwean biologist, farmer, soldier, exile, environmentalist and winner of the Banksia International Award 2003. and winner of the Buckminster Fuller Award 2010. He is the originator of the Holistic Management concept.
Savory was elected into the Rhodesian Parliament representing Matobo constituency in the 1970 election. After resigning from the Rhodesian Front in protest over its racist policies and handling of the war, Savory reformed the defunct Rhodesia Party formerly led by Sir Roy Welensky. Subsequently all moderate white parties united in opposition to Ian Smith in what was known as the National Unifying Force (NUF) led by Savory. When Savory made a public statement that if he had been born a black Rhodesian he would have been a guerilla fighter and urged white Rhodesians to understand why he would feel this, Ian Smith denounced him as a traitor. Because the NUF party would not stand by Savory he relinquished leadership to Tim Gibbs, son of Rhodesia’s last Governor. Savory continued to fight Ian Smith and his policies, in particular opposing the Internal Settlement under Bishop Abel Muzorewa. Finally faced with detention by the Smith government Savory escaped and went into self imposed exile to continue his scientific work as there was no more he felt a white Rhodesian could do to speed an end to the civil war.
Sir David Frederick Attenborough ( /ˈætənbərə/) OM, CH, CVO, CBE, FRS, FZS, FSA (born 8 May 1926) is a British broadcaster and naturalist.
His career as the face and voice of natural history programmes has endured for more than 50 years. He is best known for writing and presenting the nine Life series, in conjunction with the BBC Natural History Unit, which collectively form a comprehensive survey of all life on the planet. He is also a former senior manager at the BBC, having served as controller of BBC Two and director of programming for BBC Television in the 1960s and 1970s.
Attenborough is widely considered a national treasure in Britain, although he himself does not care for the term. He is a younger brother of director, producer and actor Richard Attenborough.
Attenborough was born in Isleworth, west London, but grew up in College House on the campus of the University College, Leicester, where his father, Frederick, was principal. He is the middle of three sons (his elder brother, Richard, became an actor and his younger brother, John, an executive at Italian car manufacturer Alfa Romeo). During World War II his parents also adopted two Jewish refugee girls from Europe.