The Mayan empire flourished in Mexico and Central America for 600 years until, around 900 AD, it suddenly disintegrated. It turns out that the Mayans themselves may have contributed to the downfall of their empire, by cutting down the jungle canopy to make way for cities and crops, which brought on drought.
A team of researchers used climate-model simulations to figure out how much the switch from forest to crops–especially corn–could alter the climate. Their results suggest that when deforestation was at its maximum, it could account for up to 60% of the drought, since the switch from trees to corn reduces the amount of water transferred from the soil to the atmosphere, which in turn reduces rainfall. The reconfiguration of the landscape may have also led to soil degradation.
On the NBC News website, Wynne Parry quotes social scientist B.L. Turner as saying, "The ninth-century collapse and abandonment of the Central Maya Lowlands in the Yucatán peninsular region were the result of complex human–environment interactions."
At the same time, trade routes shifted from land transit across the Yucatán Peninsula to sea-born ships. This may have weakened the city states, which were already dealing with environmental changes. When the ruling elites, which were (as usual) a very small portion of the population, could no longer promise the populace enough to eat, conflict increased.
Parry quotes a recent research paper as stating, "The old political and economic structure dominated by semidivine rulers decayed. Peasants, artisan-craftsmen, and others apparently abandoned their homes and cities to find better economic opportunities elsewhere in the Maya area."
The Mayans ended their own empire–let’s hope we don’t do the same! In 1998, Whitley Strieber had never heard of climate change, but the Master of the Key burst into his hotel room in Toronto and told him all about it, which led to his bestselling book "Superstorm."