Climate change linked to ancient Mayans' downfall

The modern world is not the first civilization to struggle with climate change, which according to a new study led to the collapse of Mayan society some 1,000 years ago.

Lack of rainfall over several centuries undid what had been a prosperous and relatively peaceful society, say researchers in the U.S., U.K. and Switzerland whose work appeared this week in the journal Science.

The collapse of the Mayans around AD 1100 "is an example of a sophisticated civilization failing to adapt successfully to climate change," said Dr. James Baldini, of Durham University in the U.K., in a statement.

"Periods of high rainfall increased the productivity of Mayan agricultural systems and led to a population boom and resource overexploitation. The progressively drier climate then led to political destabilization and warfare as resources were depleted," he said.

Their fate was eventually sealed "after years of hardship" and a drought that lasted almost a century from about AD1020, he added.

Mayans carved highly detailed records of their wars, alliances, the capture of enemies and other notable events on stone monuments. Researchers compiled a "war index" from those carvings and compared it to rainfall records, determined by studying mineral deposits in caves near where the Mayans once flourished.

As rainfall decreased, bloodshed and turmoil shot up. The decline started around AD 600.

The drought "set the stage for societal stress and the fragmentation of political institutions," said Professor Douglas Kennett of Pennsylvania State University in the U.S., who co-lead the study.

The team reconstructed rainfall records for the last 2,000 years. The role of climate change in the collapse of so-called "classic" Mayan civilization has been suggested before but without the support of climate records.

The Mayans of that era covered parts of what is now Mexico, Belize, Guatemala and Honduras.

It is thought the region dried up because of changes to both the El Nino climate pattern and the Intertropical Convergence Zonea belt of rainfall which circles the Earth but which, researchers suspect, changed position and for many years missed Mayan territory.