The Sahara: The lone and level sands stretch far away
by Mark Nicholson
There used to be a joke about the definition of a World Bank expert: someone who had flown over the country in question at least twice, preferably once in daylight. Having just flown over the Sahara more or less north-south for the one hundredth time (at least fifty times in daylight) I still claim to be no expert. And I have only flown over the width of the desert once and that is a much longer trip: Port Sudan to Nouakchott, the capital of Mauritania, is just over 5500 km, a trip, which is almost nothing but desert the whole way. If you want to be more adventurous, you could emulate a former SAS soldier and a woman Italian photographer who completed a 7,200 km. west-to-east trek across the Sahara on foot and on camels, a 271 day trip with camel trains that became the subject of the book[1]. An old friend I am currently staying with met him in Khartoum shortly after he had completed the walk.
I have a particular interest in the Sahara because the wife of my university supervisor worked in the Natural History Museum in London, undertook research in North Africa, and wrote several books on the origin of domestic animals[2]. Her original thesis was based on her work in the desert of southern Algeria when it was safe to travel there. Excavating to only one or two metres, she found numerous skeletons of antelope, carnivores and hippos thousands of miles from the nearest water. Using 14C dating, the bones were found to be between 6000-12000 years old. The latter coincides with the end of the last Ice age from a time when the Sahara was a verdant landscape like the Serengeti plains. More worryingly, the Sahara continues to advance as a result of land degradation in the northern Sahel and climate change. This is despite attempts to reverse the trend, such as the Africa Union’s Great Green Wall Initiative, which aims to restore 100 million hectares by 2030 and sequestrate 250 million tons of carbon.. From what I have seen of it so far in Mali and Niger, I am unimpressed by the progress to date. Satellite data shows that the Sahara has increased southwards by ten percent over the last century. The desert now covers roughly 9.2 million sq. km., about seventy times the size of England, and shared by ten countries, of which Algeria (80% desert) has the largest portion.
This time, under a July midday sun, I spent a long time peering down at the endless emptiness, far more absorbing that the old films provided by Kenya Airways. Apropos of my last scribblings on Mars, I could not help wondering why we are spending so much on trying to get to another planet when we could first restore or otherwise exploit a vast block of sand and rock for the benefit of mankind and other life forms.
There are of course vast reserves of minerals under the desert including platinum and gold, already mined on the Reguibat Shield, a one million sq. km. pre-Cambrian rock formation along the border of Mauritania and Algeria. Any philatelist of my age would have remembered stamps from Ifni, which was handed back to Morocco in 1969 from colonial Spain. As well as gold, the western republics also mine copper, lithium, titanium, rare earths and magnetite. Most of the world’s phosphates come from Morocco and Western Sahara. But the one abundant mineral which is often ignored is water. There are estimated to be around 150,000 cubic kilometres of fossil water in the Nubian Sandstone Aquifer that lies under around 2 million square kilometres of the Eastern Sahara in Egypt, Sudan, Chad and Libya, which percolated deep down during the wetter glacial periods over the last million years. That is a lot of water - about sixty times the volume of Lake Victoria. The problem is that it is fossil water and therefore not renewable. Gaddafi’s ‘Great Man-made River Project’ extracts almost 2.5 cu. km a year of that water from a series of deep wells to supply the coast; so it won’t last forever.
Only a minute percentage of the Sahara is currently used for commercial activity. There is some centre-point irrigation for wheat in Libya, otherwise only isolated patches near oases (and of course the Nile) for market gardening and date production. Tourism is still in its infancy but as urban living becomes the norm for the majority of humans, many would pay for a few nights of solitude, silence and starlit nights. In the western Sahara, there are many spectacular mountain ranges and many famous pre-historic cave paintings dating back to 6,000-12,000 b.p. A friend in Kenya takes regular desert trips into both Niger and Algeria when it is safe, which is not at the moment.
Every square metre of the desert receives 2000-3000 kwh per year so the potential for electricity generation is enormous. It has been estimated that to produce all the global electricity needs from solar panels would require using about 1-2 % (some say 5-10%) of the desert’s area. But not much has been developed because the constraints are numerous. Photovoltaics work less efficiently in hot weather and solar panels need to be kept free of dust, which requires a nearby water source. Long-distance Alternating Current (AC) transmission is inefficient and High-voltage Direct Current (HVDC) is still expensive but the technology is improving and getting cheaper all the time.
The Sahara has three vital components not found on any other planet: oxygen, water and a temperature range bearable for life. Yes, a diurnal range of 35-50o C may be hot but ironically, or dangerously, places in Europe are beginning to get as hot. Night-time temperatures in the desert can fall to near zero in winter months so counter-current heat exchangers or solar-driven air conditioners could make daytime tolerable.
If I had thirty years, I would love to experiment with horticulture and agroforestry in a real desert. I would construct high, solar panels which would allow enough light underneath for plant growth while cooling the air underneath to reduce sun damage. Water would have to be fossil water initially but if the area eventually became large enough, plant transpiration would release so much water into the atmosphere that it would begin to create its own microclimate. Climatological studies, such as those analysing landscape changes in temperate and Mediterranean zones have shown that patches reaching roughly 100 sq.km. with sufficient dense canopy cover begin to generate noticeable, measurable changes in local convective cloud formation and precipitation frequency. Er, yes, 100 square kilometres but we have to think big! To progress from the micro-level to regional level would require hundreds or even thousands of square kilometres and I will bet the Chinese will succeed first. Otherwise, nature will eventually restore the desert to what it was anyway. But, based on previous ice ages, we will have to wait another 15,000 years.
After three hours of sand viewed from 36,000 ft., the outline of the Mediterranean appeared. We overflew the sea more or less where I imagined El Alamein to be. I think that my father might not have had such a sanguine opinion of the Sahara. In 1942 and into late 1943 , he spent several months sleeping on the ground in the Western Sahara with the 8th Army, advancing and retreating from the Germans. He rarely spoke about it but when he did, he recalled only the horror of war, the noise, the dust, the heat, the bitter cold at night, the scorpions and the snakes…and sharing a bathtub of filthy water every ten days for washing, according to rank of course; officers first.
[1] Impossible Journey by Michael Asser
[2] A Natural History of Domesticated Animals by Juliet Clutton-Brock (1999)
Comments