It can be seen from the plane: crossing the Sahel, an ecoclimatic region between the Sudanese savannah and the desert, extensive landscapes of astonishing and suggestive greenery appear on the sandy plain. An unusual rarity that would indicate an essential climatic change, of a different nature and unusual consequences. Recent satellite images confirm the rebirth of life, vegetation for now, in the driest region of the world. Various studies attribute the shoots to the cyclone that caused intense rainfall last July, altering the precipitation: it exceeded the monthly average by more than 500% and flooded wide areas of the Maghreb, usually desolate.
Scientists attribute the unusual phenomenon to global warming caused by fossil fuel pollution. The positive effect of the ‘Great Green Wall’ should not be dismissed either, a forest barrier that eleven riparian countries, ravaged by recurrent droughts and grouped in the Community of Sahelo-Saharan States, have been building since 2007 from the Atlantic to the Indian Ocean. Proposed by Kenyan Wangari Maathai, Nobel Peace Prize winner in 2004, the largest reforestation effort ever undertaken has managed to reforest about 20 million hectares. The goal: to halt the desert, land degradation, and rural exodus, to provide food security for local populations. 10,000 years ago, the Sahara was a fertile garden: forests, rivers, lakes, and abundant wildlife. This is confirmed, among others, by David McGee, a paleoclimatologist at MIT: “There are remnants of human settlements, cave paintings, and fossils of large animals.” Initiated about 6,000 years ago, desertification peaked 2,700 years ago, while humans fled the area in the face of gradual infertility, estimates Francesco Pausata (University of Stockholm). Its current surface area, 9.5 million km², covers a quarter of the continent. And it grew by 10% in the last century.
Is it a mirage? McGee does not believe human action is decisive in the desertification process: “there were other natural factors”; “humans did not influence other cycles of transition from wetland to aridity either.” Can a resurgence of the sandy area then be deduced? “In a few thousand years the cycle will repeat; human action will be just one effect, alongside natural causes that could modify the planet's balance, not just in the Sahara,” opines Pausata.♦
