1) The Yok Balum cave in Belize, where precisely-dated rainfall records have been made from deposits;2) The Caana pyramid at the Caracol site in the Cayo District of Belize. Researchers believe the society collapsed a thousand years ago because it failed to cope with climate change, scientists said today; 3) A stone carving of the Venus symbol from Chichén Itzá in Yucatán, Mexico.
- Latest research shows that a prolonged drought somewhere between 800AD and 1100 brought about its collapse
By MARK PRIGG
The Classic Maya culture collapsed a thousand years ago because it failed to cope with climate change, scientists said today.
The Central American people had developed a sophisticated society, accurate calendars and complex architecture including pyramids.
They thrived during rainy periods but latest research shows that a prolonged drought somewhere between 800AD and 1100 brought about its collapse.
In a project led by scientists from Pennsylvania State University and Zurich, with expert input from Durham University, precisely-dated rainfall records have been made from deposits in local caves.
This was compared against a so-called ‘war index’, the dates of hostile events which Maya people recorded on stone monuments.
Researchers, who it is claimed have made a unique timeline linking changes in culture and climate, found war and unrest matched periods of drought.
Previously, when conditions were favourable with plentiful rain, the Maya civilisation expanded into large cities.
The findings, published in the journal Science, describe how Maya rulers commissioned monuments to record events and the research team found the frequency of texts carved in stone indicating rivalry, war and alliances increased significantly between 660AD and 900, during the drying trend.
Professor Douglas Kennett from Pennsylvania State University said: ‘It is not just climate drying and drought that is important, but the preceding conditions that helped stimulate societal complexity and population expansion.
'This set the stage for societal stress and the fragmentation of political institutions later in time as conditions became drier.'
Precise rainfall figures were calculated from chemical analysis of stalagmites in the Yok Balum caves in Belize.
Dr James Baldini, of Durham University’s Department of Earth Sciences, led the cave monitoring portion of the study.
He said: ‘The rise and fall of Mayan civilisation is an example of a sophisticated civilisation failing to adapt successfully to climate change.
'Periods of high rainfall increased the productivity of Maya agricultural systems and led to a population boom and resource overexploitation.
A MAYAN CALENDER
Periods of high and increasing rainfall coincided with a rise in population and political centers between 300 and 660 AD.
A climate reversal and drying trend between 660 and 1000 AD triggered political competition, increased warfare, overall sociopolitical instability, and finally, political collapse.
This was followed by an extended drought between 1020 and 1100 AD that likely corresponded with crop failures, death, famine, migration and, ultimately, the collapse of the Maya population.
'The progressively drier climate then led to political destabilisation and warfare as resources were depleted.
'After years of hardship, a nearly century-long drought from 1020 sealed the fate of the Classic Maya.'
The theory of climate change being to blame for the end of the Classic Maya civilisation has been suggested previously, but the link was controversial because of uncertainties over dating rainfall patterns.
The Classic Maya region covers portions of Mexico, Belize, Guatemala and Honduras.
'Here you had an amazing state-level society that had created calendars, magnificent architecture, works of art, and was engaged in trade throughout Central America,' said UC Davis anthropology professor and co-author Bruce Winterhalder.
'They were incredible craftspersons, proficient in agriculture, statesmanship and warfare—and within about 80 years, it fell completely apart.
'It's a cautionary tale about how fragile our political structure might be.
'Are we in danger the same way the Classic Maya were in danger? I don't know.
'But I suspect that just before their rapid descent and disappearance, Maya political elites were quite confident about their achievements.'
MAYAN MONUMENTS: HISTORY IN STONE
Inscribed on each monument is the date it was erected and dates of significant events, such as a ruler’s birthday or accession to power, as well as dates of some deaths, burials and major battles.
The researchers noted that the number of monuments carved decreased in the years leading to the collapse.
But the monuments made no mention of ecological events, such as storms, drought or references to crop successes or failures.