When I read about proposed alternative energy systems, they often seem to neglect the fact that removing energy from a system is still a perturbation of an energy system, just as much as adding or, in the case of climate change gases, retaining energy in the same system. So I was pleased to read about these concerns being addressed in this NewScientist (15 September 2018, paywall) article on carpeting the Sahara desert in solar panels:
COVERING the Sahara desert in solar panels and wind farms wouldn’t only help power the world, it would also improve the local climate. Rainfall there would more than double and there would be a modest increase in vegetation cover.
“There would be a slight greening of the Sahara,” says Fred Kucharski of the Abdus Salam International Centre for Theoretical Physics in Italy. This wouldn’t be enough to return the Sahara to the much greener state it was in just 6000 years ago, but the overall impact would be beneficial. And the greening effect could be amplified by other measures, such as tree planting.
Its plentiful sun and wind, sparse population and closeness to Europe make the Sahara desert prime real estate for solar and wind farms. Morocco is already building large solar plants. But any changes made to land surfaces – from cutting down forests to covering deserts in solar panels – affect climate.
According to a climate model used by a team including Kucharski, covering the entire desert in either solar or wind farms would lead to more air rising up above the Sahara and thus to more rainfall there. Building both would have an even greater effect.
It sets my mind somewhat at ease that at least we’re trying to understand all the effects of proposed changes to our natural environments, not just the anticipated positive effects.
