A new study published last month by researchers fromthe Earth and Space Sciences department at the University of Washington concludedthat there is a very small chance that the dwindlingof mountain glaciers in five continents could have occurredwithout the influence of climate change.
In2013 the Intergovernmental Panel on Climate Change(IPCC)1 believed the connection between glacial retreat andclimate change to only be “likely”, or at least a 66% probability. However, byusing statistical techniques to compare the long-term decline of 37 glaciers, researchers propose that allbut one are “very likely” – orto be more than 90% probable– to have retreated due tothe human-caused change in climate.Yet,the results from 21 of the 37 glaciers areeven more worrying. Roe and his colleges findthat it is over 99% likely – or “virtually certain” – that glacier retreat isbeing driven by climate change.
Previously,attributing any one glacier’s retreat toclimate change has been problematic due to the short glacial records and glaciers’ great natural variations. The new studyovercomes this by applying their data to a statistical ratio known as “signal-to-noise”,where “signal” is defined as glacial changes caused by climatechange and “noise” as the usual glacial fluctuations driven by the year to yearweather conditions. This ratio permitted the researchers to calculate the likelihood that each glacier’s observed retreats would have happenedeven without any background change in climate.