The Tethys Ocean finally evaporated, literally, at the Miocene’s end, and it was a spectacular exit. As part of the collision of Africa and Europe, Morocco and Spain smashed together and separated the Atlantic Ocean from the Mediterranean Sea. Then the entire Mediterranean dried out, as there was not enough regional precipitation to replenish the evaporation. Then the crashing Atlantic waves eroded through the rock and the Atlantic again filled the Mediterranean Sea in floods that may have been Earth history's most spectacular. The grinding continents then made another rock dam, the Atlantic was cut off again, and the Mediterranean once again dried up. That pattern happened more than 40 times between about 5.8 and 5.2 mya. Each drying episode, after the rock dam again separated the Atlantic from the Mediterranean, took about a thousand years and left about 70 meters of salt on the floor of the then Mediterranean Desert. The repeated episodes created 2,000-to-3,000-meter-thick sediments of , which is formed from evaporating oceans, as trapped as the Mediterranean was. Creating so much gypsum partially desalinated Earth’s oceans (a 6% lowering), raised their freezing point, and may have contributed to the growth of Antarctica’s ice sheets. Also, those drying episodes initiated great droughts in Africa and may well have spurred the evolutionary events that led to humans.
Anthropologists and primate researchers , but relatively recent scientific findings have disproven that notion. , and it is more sophisticated with great apes. It took a few million years after the human/chimp split for our ancestors to learn to , and that culture then spread widely in Africa. The , , and were probably all closely related and at least partly interdependent, but little seemed to change . Then the and possessed a larger brain, and new tools and behaviors are evident . The timeframes continually shrank between major events in the human journey. Only 200 thousand years later, and , and new behaviors are in evidence. Only 100 thousand years after that, anatomically modern humans appeared. Only 30 thousand years after that, about 170 kya, , probably due to necessity, where life once again was eked out on the margins, and those humans may have decorated their bodies. About 100 kya, innovation seems to have accelerated again, and by 75-60 kya there is evidence of . Needles and perhaps even arrowheads first appeared about 60 kya. There is no doubt among scientists that members of made those advances, and their artifacts provided evidence of increasing cultural and technical sophistication, which soon left Neanderthals and all other land animals far behind. About 75-70 kya, a , and there is controversy today whether that eruption was partly responsible for the that passed through not long afterward. What became today’s humanity seems to have nearly gone extinct at that bottleneck.
Of course, I listen to a lot of music other than the Pet Shop Boys
In the Fertile Crescent today, the ruins of hundreds of early cities are in their self-made deserts, usually buried under the silt of the erosion of exposed forest soils. As the Mediterranean Sea’s periphery became civilized, the same pattern was repeated; forests became semi-deserts and early cities were buried under silt. Before the rise of civilization, a forest ran from Morocco to Afghanistan, and only about 10% of the forest that still existed as late as 2000 BCE still remains. Everyplace that civilization exists today has been dramatically deforested. Humanity has since agriculture began. The only partial exceptions are places such as Japan, but they regenerated their forests by importing wood from foreign forests. North America and Asia have been supplying Japan with wood for generations. As civilizations wiped themselves out with their rapaciousness, some people were aware enough to lament what was happening, but they were a small minority. Usually lost in the anthropocentric view was the awesome devastation inflicted on other life forms. was only a prelude. Razing a forest to burn the wood and raise crops destroyed an entire ecosystem for short-term human benefit and left behind a lifeless desert when the last crops were wrenched from depleted soils. In the final accounting, the damage meted out to Earth’s other species, not other humans, may be humanity’s greatest crime. Humanity is the greatest destructive force on Earth since the , and our great task of devastating Earth and her denizens may be .