Wind, so­lar farms could dou­ble rain in the Sa­hara

The East African - - OUT­LOOK - By NEL­LIE PEY­TON Thom­son Reuters Foun­da­tion

LARGE-SCALE wind and so­lar farms could more than dou­ble rain­fall in the Sa­hara desert, “shocked” sci­en­tists said as the re­gion grap­ples with wide­spread hunger caused by re­cur­rent drought.

In a sim­u­lated model, wind­mills and so­lar pan­els were in­stalled across the world's largest sub­trop­i­cal desert — an un­re­al­is­tic scenario in the near fu­ture, ex­perts said.

But the mech­a­nisms dis­cov­ered may have sim­i­lar effects on a smaller scale, which fur­ther stud­ies could con­firm, said Dr Safa Mote­shar­rei, a sci­en­tist at the Univer­sity of Maryland. “We were ex­pect­ing in­creases in rain­fall and veg­e­ta­tion, but once we ran our cli­mate model and we saw how large these in­creases are, we were quite shocked,” Dr Mote­shar­rei said.

The Sa­hara desert is largely un­in­hab­it­able, but the Sa­hel — a semi-arid belt below it stretch­ing from Sene­gal to Su­dan — is one of the poor­est parts of the world with a rapidly grow­ing pop­u­la­tion that has been hard-hit by cli­mate change.

The lat­est drought in 2017 trig­gered a food cri­sis that left five mil­lion peo­ple in six coun­tries in need of food aid and children at risk of death from mal­nu­tri­tion.

Through changes in air pat­terns and sur­face tem­per­a­ture, wind­mills and so­lar pan­els cause mois­ture to rise and con­dense into rain, Dr Mote­shar­rei said. The rain boosts plant growth, which in turn causes more rain, the model showed.

At full-scale, the changes would have “ma­jor eco­log­i­cal, en­vi­ron­men­tal, and so­ci­etal im­pacts,” Dr Mote­shar­rei and col­leagues said in a paper in Science magazine last week.

If the en­tire desert were cov­ered in wind farms and one fifth in so­lar pan­els, daily av­er­age rain­fall would more than dou­ble to 0.59 mil­lime­tres from 0.24 mm, the study showed.

Even if only the north­west­ern quar­ter of the Sa­hara were cov­ered in wind­mills, rain­fall would in­crease by 0.17 mm per day on av­er­age, with the big­gest gains in the Sa­hel.

Lo­ca­tion mat­ters, so in­stal­la­tions could be placed strate­gi­cally to max­imise effects, said Dr Mote­shar­rei.

Poverty and mil­i­tancy in parts of the re­gion would make it dif­fi­cult to in­stall large-scale so­lar or wind farms even if it were tech­ni­cally fea­si­ble, said Oli Brown, an en­ergy and en­vi­ron­ment ex­pert at London-based think tank Chatham House.

It would also raise prob­lems around land rights and dis­place­ment of in­dige­nous peo­ples, he added.

“I think cov­er­ing the Sa­hara in so­lar pan­els and wind farms is highly un­re­al­is­tic in the fore­see­able fu­ture,” said Mr Brown.

Pic­ture: AFP

Tur­bines at the Ashe­goda wind farm, one of Ethiopia’s green en­ergy projects.

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