Of interest: We identified why north Africa greened approximately every 21,000 years over the past eight million years. It was caused by changes in the Earth

Of interest: We identified why north Africa greened approximately every 21,000 years over the past eight million years. It was caused by changes in the Earth’s orbital precession - the slight wobbling of the planet while rotating. This moves the Northern Hemisphere closer to the sun during the summer months. (2023) - https://theconversation.com/the-sahara-desert-used-to-be-a-green-savannah-new-research-explains-why-216555 https://theconversation.com/the-sahara-desert-used-to-be-a-g... *What Really Turned the Sahara Desert From a Green Oasis Into a Wasteland?* - 10,000 years ago, this iconic desert was unrecognizable. A new hypothesis suggests that humans may have tipped the balance (2017) https://www.smithsonianmag.com/science-nature/what-really-turned-sahara-desert-green-oasis-wasteland-180962668/ https://www.smithsonianmag.com/science-nature/what-really-tu... While I personally veer toward the more recent slight orbital variation cause, neither account factors much in the current AGW debate .. cyclic changes in local regions of the planet are a distinct issue from a steady rise in global atmospheric insulation properties.