Glaciers at roof of the world melting at terrifying rate

By Stephen Beech via SWNS

Glaciers at the roof of the world are melting at an "exceptional rate" due to global warming, warns new research.

The accelerating melting of the Himalayan glaciers threatens the water supply of millions of people in Asia, say British scientists who conducted the study.

They have calculated that they have lost between 390 cubic kilometres and 586 cubic kilometres of ice – the equivalent of all the ice contained today in the central European Alps, the Caucasus, and Scandinavia combined.

The study, led by University of Leeds researchers, concludes that in recent decades the Himalayan glaciers have lost ice TEN TIMES more quickly than on average since the last major glacier expansion 400 to 700 years ago, a period known as the Little Ice Age.

The findings, published in the journal Scientific Reports, also reveal that Himalayan glaciers are shrinking far more rapidly than glaciers in other parts of the world.

The research team made a reconstruction of the size and ice surfaces of 14,798 Himalayan glaciers during the Little Ice Age.

They calculate that the glaciers have lost around 40 per cent of their area – shrinking from a peak of 28,000 square kilometres to around 19,600 km2 today.

During that period they have also lost between 390 cubic kilometres and 586 cubic kilometres of ice – the equivalent of all the ice contained today in the central European Alps, the Caucasus, and Scandinavia combined.

The team calculate that the water released through that melting has raised sea levels across the world by between 0.92 mm and 1.38 MMS.

Corresponding author Dr. Jonathan Carrivick, deputy head of the University of Leeds School of Geography, said: “Our findings clearly show that ice is now being lost from Himalayan glaciers at a rate that is at least ten times higher than the average rate over past centuries.

"This acceleration in the rate of loss has only emerged within the last few decades, and coincides with human-induced climate change.”

The Himalayan mountain range is home to the world’s third-largest amount of glacier ice, after Antarctica and the Arctic and is often referred to as 'the Third Pole’.

The researchers say that acceleration of melting of Himalayan glaciers has "significant" implications for hundreds of millions of people who depend on Asia’s major river systems for food and energy. These rivers include the Ganges, Brahmaputra and Indus.

The team used satellite images and digital elevation models to produce outlines of the glaciers’ extent 400 to 700 years ago and to ‘reconstruct’ the ice surface.

Satellite images revealed ridges that mark the former glacier boundaries and the researchers used the geometry of these ridges to estimate the former glacier extent and ice surface elevation.

Comparing the glacier reconstruction to the glacier now, determined the volume and mass loss between the Little Ice Age and now.

The Himalayan glaciers are generally losing mass faster in the eastern regions - taking in east Nepal and Bhutan north of the main divide.

The study suggests the variation is probably due to differences in geographical features on the two sides of the mountain range and their interaction with the atmosphere, resulting in different weather patterns.

Himalayan glaciers are also declining faster where they end in lakes, which have several warming effects, rather than where they end on land.

The number and size of these lakes are increasing so continued acceleration in mass loss can be expected.

Similarly, glaciers that have significant amounts of natural debris on their surfaces are also losing mass more quickly: they contributed around 46.5 per cent of total volume loss despite making up only around 7.5 per cent of the total number of glaciers.

Dr Carrivick said: “While we must act urgently to reduce and mitigate the impact of human-made climate change on the glaciers and meltwater-fed rivers, the modelling of that impact on glaciers must also take account of the role of factors such as lakes and debris.”

Co-author Dr Simon Cook, of the University of Dundee, added: “People in the region are already seeing changes that are beyond anything witnessed for centuries.

"This research is just the latest confirmation that those changes are accelerating and that they will have a significant impact on entire nations and regions.”