Free Astronomy Magazine January-February 2022

33 ASTRO PUBLISHING ground and sea levels only slightly lower than those of the CTM. While the CTM lasted for millions of years, the PETM lasted “only” about 200,000 years. By considering the Earth’s climatological history, we re- alize that the current geological epoch, the Holocene (second epoch of the Quaternary period, after the Pleistocene), which began 11,700 years ago, is, in fact, characterized by unusually cold average tempera- tures. Geologists consider our epoch as an interglacial period included in the current ice age, which began about 2.5 million years ago with the Pleistocene. Technically, we are living in an ice age. Why, then, is global warming of just 1.5 °C in two and a half cen- turies so worrying? The reasons are different, but almost all of them are linked to the fact that, starting about 11,000 years ago, humans be- came more and more resident, link- ing all the activities necessary for T his map represents the spread of herding in the Fertile Crescent, between 11,000 and 8,500 years ago. In the same period and in the same regions, agri- culture also spread. The two practices made the human being resident and, therefore, more vulnerable to climate change. Legend: orange, goats (Capra hir- cus); blue, sheep (Ovis aries); green, cattle (Bos taurus); fuchsia, pigs (Sus scrofa). D iagram of an indus- trial plant that pro- duces electricity from the combustion of coal, the most polluting of fossil fuels. Over 63% of the en- ergy that drives electric cars is produced in this way. [CO2CRC]