1,200 year-old discovery could explain why Mayan civilisation completely disappeared

Around 1,200 years ago the Mayan civilisation in Central America collapsed, entire cities were abandoned and the Maya vanished from parts of the world they had once called home.

It was not the end of the Maya people but their strength diminished and in the following centuries they never returned to the prominence they once had, what happened to them and where they went has been the subject of much study.

How a people could build great cities and end up abandoning them has long been a fascination of historians and scientists, in the span of around 100 years the urbanised lowlands of the Yucatán Peninsula went from populated cities to ghost towns.

There have been many theories put forward as to what happened, but a study into ice from 1,200 years ago may help explain what happened to the Maya.

One of the researchers looking into the collapse of the Maya was Professor Paul Mayewski of the University of Maine, who for the 2001 documentary Ancient Apocalypse took samples of ice cores from 1,200 years ago and studied them.

Some 1,200 years ago the Maya abandoned several cities and the exact reason isn't known (Edwin Remsberg/VWPics/Universal Images Group via Getty Images)

"First thing that we looked at was our record of ammonium," he explained of how studying very old ice samples could tell you a lot about the past.

"And ammonium is a chemical that gets up into the atmosphere, which tell us whether or not there was a lot of vegetation in the northern hemisphere.

If there's a lot of vegetation, one assumes it was probably warm and wet. Low amounts, that it was probably drought conditions, that there weren't a lot of plants, the soils had probably dried up."

When he studied the 1,200-year-old ice sample he found a significant drop in ammonium, which to him indicated there had been a significant drought which would have caused crops to fail, meaning there wouldn't have been enough food for the cities and could have caused people to move away.

It's a possible reason why the Maya abandoned some of their cities over the span of 100 years.

A study into how cutting down trees to make room for farmland warned that fewer trees in an area reduces a land's ability to absorb solar radiation, which in turn means less water evaporating there which ends up turning into rain.

Less rain can lead to droughts, crop failure and an inability to produce enough food to sustain cities in a process ironically started by deforestation to make more land for food production.

This is one of the several theories on why the Maya civilisation was significantly diminished 1,200 years ago and caused them to 'vanish' from large swathes of territory they once controlled, leaving behind abandoned cities in their wake.

However, there are several other theories including power struggles, political unrest and overpopulation, and when the Spanish turned up centuries later the diseases they brought with them had a catastrophic impact on populations native to the lands they conquered.

Despite everything they've been through the Maya still exist as a people today in Central America.