The glacier covers 86 sq km in the Swiss Alps and is estimated to hold around 11 billion tonnes of ice.

The mighty Aletsch -- the largest glacier in the Alps -- could completely disappear by the end of this century if nothing is done to rein in climate change, a study showed Thursday.

A team of researchers in Switzerland has used a cutting-edge simulation to show how the Aletsch Glacier will change as the planet continues to warm, the ETH technical university in Zurich said in a statement.

The glacier, which covers 86 square kilometres (33 square miles) in the Swiss Alps, and is estimated to hold around 11 billion tonnes of ice, has already seen its tongue recede by about one kilometre (0.6 miles) since the turn of the century.

Scientists are predicting that trend will continue even if the world is able to meet the 2015 Paris Agreement target of capping global warming at "well below" 2 degrees Celsius.

The ETH research team said that even in the best case scenario the glacier would lose 50 percent of its volume and length by year 2100, while in the worst-case scenario, "a couple patches of ice will be all that's left."

Aletsch is one of more than 4,000 glaciers -- vast, ancient reserves of ice -- dotted throughout the Alps, providing seasonal water to millions and forming some of Europe's most stunning landscapes.

In a study earlier this year, ETH researchers determined that more than 90 percent of those glaciers will disappear by 2100 if greenhouse gas emissions are left unchecked.

Thursday's study meanwhile focused specifically on the impact on the biggest glacier of them all.

"Much more critical"

Guillaume Jouvet and Matthias Huss at ETH's Laboratory of Hydraulics, Hydrology and Glaciology applied 3D glacier model simulations for the ice retreat using different established climate scenarios for Switzerland.

They show the glacier seen from the Eggishorn and Jungfraujoch peaks, which tower 2,927 and 3,466 metres above sea level, as it rapidly recedes over the coming eight decades.

They focused on three scenarios determined by different concentrations of CO2 in the atmosphere, and thus also different levels of global warming.

Even if warming is limited to below 2C, and the climate is stabilised by 2040, "we have to assume that the Aletsch Glacier will keep retreating until the end of the century," Jouvet said in the statement, pointing out that large glaciers are very slow to react to climate change.

This, he said, "means both ice volume and length will be reduced by more than half of what they are today".

If the global community is unable to pull together and effectively limit the planet-warming gases emitted through burning fossil fuels, construction, aviation and mega-farming, the situation for the glacier will be "much more critical", ETH said.

If Switzerland's climate warms by 4-8C by 2100 -- an "unfavourable but unfortunately fully realistic scenario" -- only "a couple of measly patches of ice" will remain.

And Konkordiaplatz, which is directly below Jungfraujoch and still covered in about 800 metres (half a mile) of ice, will be completely ice-free," Jouvet said.