Incas first victims of greenhouse gases

The ancient Incas were among the first victims of man-made greenhouse gases when Spanish Conquistadors forced them to mine silver at Potosi 240 years before the industrial revolution, it was claimed yesterday.

The earliest evidence of large-scale human-produced greenhouse gases in South America was found encased in ice in the Andes.

In the 16th century during its conquest of South America the Spanish forced Incas to work in the mountaintop mines of Potosi in what is now Bolivia -- then the largest source of silver in the world.

The indigenous population already knew how to refine the metal but in 1572 the Spanish introduced a new technology that boosted production many times over and sent thick clouds of lead dust rising over the Andes for the first time in history.

Winds carried some of that pollution 500 miles northwest into Peru where tiny remnants of it settled on the Quelccaya Ice Cap.

There it stayed -- buried under hundreds of years of snow and ice -- until researchers from Ohio State University found it in 2003.

Now in Proceedings of the National Academy of Sciences they report the discovery of a layer within an ice core that dates to the Spanish conquest, contains bits of lead and bears the chemical signature of the silver mines of Potosi.

The core makes Quelccaya one of only a few select sites on the planet where the pre-industrial human impact on air quality can be studied today.

Dr Paolo Gabrielli said, “This evidence supports the idea human impact on the environment was widespread even before the industrial revolution.”

The researchers found a spike in bismuth -- a chemical by-product of mining metals -- around 1480 when the Inca Empire was expanding.

The chemical signature in the Quelccaya ice suggests most of the pollution likely came from Potosi where the Spanish produced the vast majority of silver.

This latest ice core from Quelccaya shows that humans generated substantial pollution in the 16th century.