A new study on ice loss calculations shows some mountain glaciers are currently melting at a rate 100 times faster than at any other period during the last 350 years, setting the stage for major impacts on fresh water supplies and agriculture production.
The Patagonia glaciers of South America were used as the study group to determine the rate at which these glaciers are melting and scientists have determined that glacial ice loss since 1980 is occurring at an alarming rate.
The study, Global sea-level contribution from the Patagonian Icefields since the Little Ice Age Maximum (pdf), was published online at Nature Geoscience and reveals that of the 270 glaciers in Patagonia at least one square kilometer is size, 606 cubic kilometers of ice has melted in the last 350 years, with possibly an additional 123 cubic kilometers melting.
“The glaciers have lost a lot less ice up until 30 years ago than had been thought. The real killer is that the rate of loss has gone up 100 times above the long-term average. It's scary,” said Professor Neil Glasser of Aberystwyth University, leader of the research team, noted The Independent.
The study on melting glaciers was based in part on mountain trimlines, the point at which vegetation begins on mountains, determined by the glaciers.
It is the first study of melting glaciers to cover such a period of time and was based on three-dimensional calculations of each glacier at its peak during the study period. Field determinations, including terminal moraine locations and mountain trimlines, the starting point for vegetation, were used with remote sensing to reconstruct the receding glaciers.
The southern Patagonian Icefields are situated at the same latitude as are the Alps in the northern hemisphere. These glaciers are also melting, and Glasser notes those glaciers are likely retreating much faster than thought. “If we looked at them, I'm pretty sure we would find they are also speeding up their loss rate,” he said, according to The Independent.
Across the planet, billions of people depend on seasonal glacial meltwater, with large cities centered on such supplies. As these glaciers continue disappearing, new battles are likely to erupt over fresh water, the basic necessity of life.
In Peru, the city of Lima bears this out. With a population of more than eight million, it is the world’s second largest city situated in an arid region. It receives the majority of its drinking water from the Quelccaya Ice Cap in the Andes Mountains. Since 1978, the Quelccaya Ice Cap has lost over 20 percent of its mass, with some experts suggesting that number is closer to 30 percent.
Aerial images taken of the ice cap between 1963 and 1978 show an annual retreat of 15 feet. However, data taken over the last decade reveals that annual retreat has accelerated to 672 feet.
The study determined that glacial melt is currently occurring at a faster rate than at any other time in the last 350 years. On Glacier Grey, in Chile's Parque Nacional Torres del Paine, another glacial pool begins forming as the glacier retreats by more than 450 feet annually.
Glacier Grey, located in Patagonia Sur’s Parque Nacional Torres del Paine, is another example of massive glacial retreat in recent years. Within the last 15 years it has seen its retreat go from around 45 feet annually to more than 450 feet per year.
According to the study, glaciers in the Patagonian Icefields are believed to have contributed around 10 percent of total sea-level rise caused by the planet’s melting mountain glaciers over the last 50 years.
In conclusion, the study notes
We conclude that the melt rate and sea-level contribution of the Patagonian Icefields increased markedly in the twentieth century.