Two annually dated ice cores drawn from the tropical Peruvian Andes reveal Earth's tropical climate history in unprecedented detail -- year by year, for nearly 1,800 years. Researchers at The Ohio State University retrieved the cores from a Peruvian ice cap in 2003, and then noticed some startling similarities to other ice cores that they had retrieved from Tibet and the Himalayas. Patterns in the chemical composition of certain layers matched up, even though the cores were taken from opposite sides of the planet.
In the April 4, 2013 online edition of the journal Science Express, they describe the find, which they call the first annually resolved "Rosetta Stone" with which to compare other climate histories from Earth's tropical and subtropical regions over the last two millennia. The cores provide a new tool for researchers to study Earth's past climate, and better understand the climate changes that are happening today."These ice cores provide the longest and highest-resolution tropical ice core record to date," said Lonnie Thompson, distinguished university professor of earth sciences at Ohio State and lead author of the study."In fact, having drilled ice cores throughout the tropics for more than 30 years, we now know that this is the highest-resolution tropical ice core record that is likely to be retrieved."
The cores will provide a permanent record for future use by climate scientists, Thompson added. This is very important, as plants captured by the advancing ice cap 6,000 years ago are now emerging along its retreating margins, which shows that Quelccaya is now smaller than it has been in six thousand years.