At four different locations on Baffin Island, Professor Gifford Miller and his University of Colorado Boulder colleagues used radiocarbon dating to show that dead moss clumps emerging from receding ice caps had not been exposed to the elements since at least 44,000–51,000 years ago.
Radiocarbon dating is only accurate to about 50,000 years. The researchers used data from ice cores previously retrieved by international teams from the nearby Greenland Ice Sheet to reconstruct Baffin Island’s past climate beyond this limit. The results showed that the last time that summer temperatures in the Arctic were as warm as they are today was probably about 120,000 years ago, near the end of the last interglacial period. ‘We suggest this is the most likely age of these samples,’ said Miller.
‘The key piece here is just how unprecedented the warming of Arctic Canada is,’ he added. ‘This study really says the warming we are seeing is outside any kind of known natural variability, and it has to be due to increased greenhouse gases in the atmosphere.’
This story was published in the December 2013 edition of Geographical Magazine