Climate changes causes, manifestations, and effects in sahel
Contenu
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Titre
Climate changes causes, manifestations, and effects in sahel
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Description
Published late 2013, the latest IPCC report demonstrates that the link between human activities and increasing temperatures observed since 1950 is very likely. These activities are manifested by massive emissions of Greenhouse Gases (GHGs) in the atmosphere, including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Responsibilities are shared unequally between countries, but effects apply to everyone, especially African countries, particularly subSaharan ones. Yet, the African continent as a whole represents only 3.4& of global GHGs emissions and the CILSS/ECOWAS countries all together less than 1& of global emissions. At the global level, since the early 20th century, the temperature of the surface of the earth has increased by 0.8°C and sea levels rose from 19 cm. Each of the last three decades has been successively warmer than all previous decades since 1850! At the level of sub-Saharan Africa, climate changes are also important and disrupt farming activities, backbone of the economy: increase in the frequency of hot days and nights, heat waves, rainfall anomalies (annual and monthly volumes, heavy rains, consecutive dry days, start and end of the rainy season, etc.), increase in extreme weather events, etc. The example of the rainfall is striking: after experiencing an unprecedented drought in the world since the 1970s, West Africa has benefited from increased rainfall since the beginning of the 1990s, but with a strong interannual variability and more frequent episodes of heavy rains. The duration of the rainy season has decreased, while the frequency of flooding has increased. The impacts of climate changes are perceived by the West African populations, but their causes are not well understood. Informing these populations on climate changes, which will grow worse, is therefore an urgent challenge.
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Sujet
Changement climatique
Effets
Causes
Afrique de l'Ouest