Glaciers are contributing more and more to the increasing sea level rise, according to a new study which looked at 270 of the largest outlet glaciers of the South and North Patagonian Icefields of South America.
They found that melting mountain glaciers are contributing more to sea level rise than any time in the last 350 years.
“The work is significant because it is the first time anyone has made a direct estimate of the sea-level contribution from glaciers since the peak of the Industrial Revolution,” said Dr Stephan Harrison, from the University of Exeter’s Geography department. “Our results show that recent estimates of rates of glacier contribution to sea-level rise are well above the long-term average.”
The research team, made up of scientists from the University of Exeter, Aberystwyth University, and Stockholm University, mapped changes in the position of the Patagonian glaciers since the Little Ice Age, a period of extreme cooling that occurred between the 16th to 19th centuries which marks the last time the glaciers were significantly larger than they are in warmer periods.
They calculated the volume of ice lost by the glaciers as they retreated and thinned over the time since the end of the Little Ice Age, and compared these volume losses to the rates of change monitored over the past 30 years. Their findings showed that the rate at which glaciers are currently losing volume is ten to a hundred times faster than the 350 year long-term average.
“Previous estimates of sea-level contribution from mountain glaciers are based on very short timescales. They cover only the last 30 years or so when satellite images can be used to calculate rates of glacier volume change,” said lead author of the study, Professor Neil Glasser of Aberystwyth University.
“We took a different approach by using a new method that allows us to look at longer timescales. We knew that glaciers in South America were much bigger during the Little Ice Age so we mapped the extent of the glaciers at that time and calculated how much ice has been lost by the retreat and thinning of the glaciers.”
The conclusions of the study note that these glaciers have been rapidly increasing their contribution to the global sea level rise.