Wetter climate predicted for African Sahel
How to help the most vulnerable?
JB: This is Earth & Sky, on persistent drought in the Sahel region of Africa.
DB: Drought in Africa created widespread famine that, since the 1970s, has killed more than a million people. Scientists have struggled to explain the drought. They’ve considered natural climate change and looked at human over-use of resources: overgrazing, deforestation, poor land management. They’ve considered at air pollution from Europe and North America. Could this pollution be changing the properties of clouds over the Atlantic. Could it be disturbing the monsoons and shifting the rains to the south?
JB: Martin Hoerling is a meteorologist with the National Oceanic and Atmospheric Administration, or NOAA. He studies Africa’s Sahel, using computer modelling. The current theories on drought in the Sahel center on the North and South Atlantic Oceans, whose surface temperatures are known to be rising due to global warming. The work of Hoerling and others indicates a slight increase in precipitation in the Sahel over the coming century.
Martin Hoerling: We would expect that there should be a wettening, if you will, of the Sahel. And indeed one does see that happen in the majority of the 20 models that have been used to predict the 21st century climate.
DB: But, according to Hoerling . . .
Martin Hoerling: These models aren’t perfect. So there’s limitations to these models to say the least.
JB: More at earthsky.org. Our thanks today to NOAA. We’re Block and Byrd for Earth & Sky.
Additional Teacher Resources
NOAA: The Great Drying of Africa
Located just south of the scorching sands of the Sahara Desert is an expansive, semi-arid region of Africa called the Sahel. This sparsely vegetated area receives an average of four to eight inches of rainfall per year during its July to September monsoon season. During this warm time of year, summer rains are usually abundant with the heating of the sun. However, the Sahel experienced a severe drying trend during the last half of the 20th century that led to devastating drought during the 1970s and 1980s, and resulted in widespread famine and the loss of more than 1,000,000 human lives.
NOAA: GFDL Climate Research Highlights Image Gallery Sahel Drought: Past Problems, an Uncertain Future
This animation depicts the time evolution of five-year averages of African precipitation as simulated in the GFDL CM2.0 model for the period 1901 to 2100. On the left side of the frame, rather than mapping rainfall amounts in units of inches or millimeters, we have chosen to bin the values at each model grid point into five categories (seen as five colors in the color bar at the bottom of the plot).
