The Maya could have aided in their own collapse by changing their local climate as they cleared away forests for crops, worsening an already present drought, according to a new study.

Prolonged droughts are thought to have been a contributing factor in the demise of the Maya empire just over a thousand years ago in what is now southern Mexico and northern Central America. The Maya numbered more than 19 million during their so-called classic period between  250 and 900 AD.

However, in a study released this week in the journal Geophysical Research Letters, researchers with the NASA Goddard Institute for Space Studies now say clearing away jungle might have quickened their collapse.

"We’re not saying deforestation explains the entire drought, but it does explain a substantial portion of the overall drying that is thought to have occurred," said the study’s lead author and climate modeler, Benjamin Cook, with Columbia University's Lamont-Doherty Earth Observatory

Using computer simulations they found that rainfall in the greatly logged Yucatan peninsula would have decreased by as much as 15 per cent during the peak of deforestation, and that an estimated 60 per cent of the drying out of the land in general was a result of the Maya's deforestation. 

Cook said that as crops replaced forest, more sunlight bounced back into space and the ground absorbed less energy from the sun. That meant less water would evaporate from the surface, leading to less moisture and fewer rainmaking clouds.