The Little Ice Age was not a global phenomena and the human population did not suffer very much.
Geologists and paleontologists have found that, in the last 100 million years, global temperatures have peaked twice. One spike was the Cretaceous Hot Greenhouse roughly 92 million years ago, about 25 million years before Earth’s last dinosaurs went extinct. Widespread volcanic activity may have boosted atmospheric carbon dioxide. Temperatures were so high that champsosaurs (crocodile-like reptiles) lived as far north as the Canadian Arctic, and warm-temperature forests thrived near the South Pole.
Another hothouse period was the Paleocene-Eocene Thermal Maximum (PETM) about 55-56 million years ago. Though not quite as hot as the Cretaceous hothouse, the PETM brought rapidly rising temperatures. During much of the Paleocene and early Eocene, the poles were free of ice caps, and palm trees and crocodiles lived above the Arctic Circle.
During the PETM, the global mean temperature appears to have risen by as much as 5-8°C (9-14°F) to an average temperature as high as 73°F. (Again, today’s global average is shy of 60°F.) At roughly the same time, paleoclimate data like fossilized phytoplankton and ocean sediments record a massive release of carbon dioxide into the atmosphere, at least doubling or possibly even quadrupling the background concentrations.
It is still uncertain where all the carbon dioxide came from and what the exact sequence of events was. Scientists have considered the drying up of large inland seas, volcanic activity, thawing permafrost, release of methane from warming ocean sediments, huge wildfires, and even—briefly—a comet.
Modern human civilization, with its permanent agriculture and settlements, has developed over just the past 10,000 years or so. The period has generally been one of low temperatures and relative global (if not regional) climate stability. Compared to most of Earth’s history, today is unusually cold; we now live in what geologists call an interglacial—a period between glaciations of an ice age. But as greenhouse-gas emissions warm Earth’s climate, it’s possible our planet has seen its last glaciation for a long time.
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Bottom line is that humans flourished during the cold periods of the last 100,000 years. Now with human burning of fossil fuels the CO2 levels are rising and along with global temperatures. Humans are not adapted to the extreme heat that is killing many people. It is easier to live in cold weather climate with more clothes - than living in hot weather climates with no clothes.
