WATER: Sahel Region Flashcards
how has human activity contributed to an increased risk of drought in the Sahel Region?
a
causes of desertification
Changing rainfall patterns with rainfall becoming less reliable, seasonally and annually. The occasional drought year sometimes extends to several years.
The vegetation cover becomes stressed and begins to die, leaving bare soil.
The bare soil is eroded by wind and the occasional intense shower.
When rain does fall, it is often only for short, intense periods. This makes it difficult for the remaining soil to capture and store it.
Rainfall
the northern Sahel region is experiencing a 30-40% annual departure from normal rainfall
human factors causing drought
Population growth:
rapid population growth puts pressure on the land to grow more food
migrants fleeing from one disaster area help to make another
Sahel has one of the world’s highest poverty rates and lowest development levels
Overgrazing:
too many goats, sheep and cattle destroy the vegetation cover
Overcultivation:
intense use of marginal land exhausts the soil and crops will not grow
Deforestation:
trees are cut down for fuel, fencing and housing. The roots no longer bind the soil, and erosion ensues.
Frequent civil wars:
crops, livestock and homes getting deliberately destroyed.
air pollution:
pollutants from Europe and North America cause atmospheric cooling , changing the global heat budget and the atmosphere circulation so that tropical rains associated with ITCZ did not arrive
anthropogenic climate change:
higher sea-surface temperatures in the tropical Atlantic Ocean means that rain-bearing winds that move over the Sahel fail
meteorological factors causing drought
natural blocking of the STR
ENSO cycles
2015-2016 drought
increased water stress
El Nino conditions
temperatures were 2 degrees higher than average in December 2015 and January 2016, with lower rainfall
location
The Sahel region of Africa stretches from Mauritania eastwards to Ethiopia on the southern edge of the Sahara Desert
semi-arid conditions with occasional severe droughts
