Here, in the meantime, is an advanced American civilization, and unlike the others on this list so far, their climate change-induced collapse may have been at least partly of their own doing.
The Maya are actually both an exemplary and cautionary tale of adaptation. Around 2,000 years ago, a rise in sea levels swamped coastal farms, according to this research. So the Maya simply moved inland, or reclaimed the farms for wetland agriculture.
The system fed the burgeoning Maya population adequately, but a centuries-long wet period beginning from the 440s to 660s A.D. really propelled the civilization to prominence.
An advanced culture bloomed in dozens of sophisticated cities, the largest ones boasting around 70,000 people and easily rivaling most of Europe’s communities at the time. Philosophy and science also blossomed – these are the people who invented the Long Count calendar, after all.
Then climate patterns shifted, and until around 1,000 A.D., a drying trend slowly led to declining crop yields and increased warfare. A drought in the first century of the 2nd Millennium dealt the death blow. The Maya people still exist, scattered across Mexico, Guatemala and Belize, but their huge cities were long abandoned by the time Spanish Conquistadors arrived in the 1500s.
In this case, though, the Maya may actually have sped up their own demise. Massive urban development led to wide-scale deforestation, reducing atmospheric moisture by 5-15 per cent. Doesn’t sound like a lot, but this research says that could have accounted for 60 per cent of the drying of the region during the collapse.
A professor quoted in this National Geographic article warns against relying too much on this example as an indicator of what might happen in the region if if the same drying out happens today – our modern societies are radically different from the classical Maya.
Still, the incredible impact that kind of deforestation had on the area is worth studying, and keeping in mind, as we consider the human factor in climate change.
Almost a thousand years ago, the community of Cahokia on the Mississippi in southwestern Illinois was booming. Its inhabitants built massive earthen mounds, relied on an extensive farming complex for support, and thronged walkways tens of thousands strong, easily dwarfing most European capitals at the time.
But by 1300 A.D., everybody had apparently packed up and left. What went wrong?
Base on tree ring analysis in the area, the theory is the rapid development of the site coincided with one of the wettest periods in the area, between 1050 and 1100, enough to sustain a massive agricultural revolution.
Easy come, easy go. From 1100, the region suffered 150 years of drought cycles. One drought is said to have lasted 15 years. The civilization had reached a peak under a particular set of climate conditions. When those changed for the worse, the results were predictable.
With falling crop yields, the population plummeted. In 1200, it was half what it was at the peak, and by 1350, the site was all but abandoned.
As with other civilizations suffering the same fate, there’s evidence of massive and rising social unrest. The 20,000 log palisade wall the city’s rulers built is not the kind of decoration you’d expect in a civilization in a golden age of peace and harmony.
By the time European explorers reached the region, all that remained of the largest pre-contact concentration of indigenous people north of Mexico were the huge earth mounds they’d left behind.
Everyone knows the story of the Viking landing in Newfoundland, but even before then, Scandinavians were setting in Greenland, building what, at its peak, was a thriving colony that lasted almost 500 years.
This wasn’t a blasted outpost: Up to 5,000 people may have called Greenland home, along with dozens of churches, numerous farms and even bishops.
All was well, so long as the climate cooperated. While more temperate than today, according to Archaeology Magazine, ice-core samples from the 1990s show a definite cooldown beginning in the mid-twelfth century. By the 1500s, the colony was basically gone
The thing about the Greenland Vikings, however, is not that climate change drove them out, it's that they refused to adapt to it.
Although the cooldown meant an end to the farming and husbandry they were used to, research by a Danish-Canadian team shows they simply turned to the sea, and quite rapidly, with seafood eventually making up 80 per cent of their diet.
Although life in Arctic-like climes is hard, it needn’t mean the end of settlement (just ask the Inuit, with whom the Greenlanders came into occasional content). The Norse settlers were simply too set in their ways, even refusing to adapt the hunting methods and clothing of the Inuit.
Add to that more treacherous trade routes due to increased sea ice, falling demand for their exports, and a growing sense of isolation from their cultural counterparts in Europe, and you have plenty of reasons for young Greenlanders to leave the colony.
The island was abandoned by Europeans by 1500, although eventually Denmark would take possession of it. It is now a Danish territory, with substantial home rule.