阅读原文：The derts, which already occupy approximately a fourth of the Earth's land surface, have in recent decades been increasing at an alarming pace. The expansion of dertlike conditions into areas
考古证明地球3600年周期三心是哪三心∙3600 Years Ago: ∙∙- In the July 15, 1999 paper published by the journal, Geophysical Rearch Letters, the Sahara dert's arid climate change occurred quickly
