Scientists are worried: the 3rd largest ice reserve in the world is collapsing

It supplies water to nearly two billion people. With almost two million square kilometres, the high tibetan plateau located north of the Himalayas is sometimes nicknamed the water tower of Asia, or even the third pole, because of the amount of ice it contains. But, as we have already known for years, it is melting faster and faster. Between the years 2000 and 2018, the mass total glaciers went from 340 gigatonnes to 166 gigatonnes, a decrease of more than 50%!

In question, global warming, of course: its effects are felt all the more at altitude. Temperatures are rising, and melting the glaciers. But it’s not that simple, as a study published in the journal Nature reviews earth & environmentwhich describes the current situation and its possible evolution.

Indeed, if the basis is indeed a melting stored ice, this melting has a number of consequences: first of all, the ice-liquid phase change creates, according to the researchers, a “south-north disparity due to the spatio-temporal interaction between winds west and the monsoon Indian. » More specifically, this means that the atmospheric circulations have changed due to an increase in the proportion of water liquidand then modified the distribution of water resources according to the regions.

The consequences are likely to vary with the acceleration of warming

More precisely, the water flows more and more towards the north, and less and less towards the south. This imbalance tends to increase, and in the long term, the exoreic basins of the south – which plunge towards the sea – risk drying up, and the endorheic basins – which are closed – risk ending up submerged. the global warming should amplify this imbalance, further fueling “ the basins of the Yellow and Yangtze rivers » and, conversely, causing a shortage in “The Indus and Amu Darya basins”. For the Indus, in particular, the researchers are concerned because, on the banks of the river, there are many agricultural areas that require irrigation important.

In total, millions of people are affected who could well run out of water soon. “Such an imbalance is expected to pose a great challenge to the balance between supply and demand of water resources in downstream regions”, worried Professor Yao Tandong, first author of the study. In the future, Y.Tandong hopes to implement better measurement methods. “We need more accurate predictions of future water supply to assess mitigation and adaptation strategies for the region.”

The Himalayan glaciers are melting at an alarming rate!

Article of Nathalie Mayer published on 29/11/2021

Scientists usually refer to the Himalayas as the “third pole”. Because its glaciers contain the third largest amount of ice in the world. And today, researchers are telling us that, under the effect of anthropogenic global warming, these glaciers are melting at a speed record. Threatening in particular the water supply of millions of people.

All over the world, ice is melting. A consequence of global warming anthropogenic. And some University of Leeds researchers (United Kingdom) tell us today that the glaciers of the Himalayas, in particular, are melting at a speed that they themselves qualify as exceptional. In recent decades, they have lost ice ten times faster than average since their last major expansion during the Little Ice Age between 400 and 700 years ago.

The researchers rely to say this on a reconstruction of nearly 15,000 Himalayan glaciers. While at their peak they covered an area of ​​some 28,000 square kilometres, today they already cover only about 19,600 square kilometres. That is a loss of ice of no less than 40% in area. At the same time, they also lost volume, dropping from 596 cubic kilometers to just 309 cubic kilometers. A loss equivalent to all the ice of the Alps, the Caucasus and Scandinavia combined.

A meltdown with serious consequences

The researchers point out that the loss of ice is even more marked in the eastern regions. The reason: different weather patterns. The melting is also more marked for glaciers that have large amounts of natural debris on their surface. By volume, they are responsible for almost 50% of the loss of ice while they only account for some 7.5% of the total glaciers. But ice loss is also greater for glaciers that end up in lakes. Thus, with an increase in the number and size of these Himalayan lakesthe rate of melting could accelerate further.

If this melting of the Himalayan glaciers has already caused a rise in sea level of around 1 millimetre, it is above all for thewater supply and in energy hundreds of millions of people in the region that scientists worry about. Because the acceleration of the phenomenon will have important implications on the main river systems of the Himalayas. The inhabitants of the region are already seeing changes that seem to be accelerating.

Himalayas: two-thirds of glaciers will melt by the end of the century

The “third terrestrial pole”, which includes the entire Himalayan chain, will experience an unprecedented melting, with consequences for nearly two billion inhabitants. Mountain areas are particularly sensitive to global warming.

Article of Celine Deluzarche published on 06/02/2019

” It’s the climate crisis you haven’t heard of », says Philippus Wester, head ofa study led by Icimod, an intergovernmental organization based in Kathmandu (Nepal). According to’International Center for Integrated Mountain Development (Icimod), two thirds of the glaciers of the Hindu Kush and the Himalayas (HKH) could to melt by the end of the century if the planet remains on the same trajectory ofemissions of greenhouse gas.

Global warming and pollution: the deadly cocktail for glaciers

Qualified as the “third pole” by scientists for its gigantic ice reserves, this mountainous region, extending over 3,500 km and crossing eight countries, is likely to see its glaciers largely disappear. Even limiting the rise in temperature to the limit of 2.1 ° C as provided for in the Paris Agreement, a third will have melted by 2100, warn experts.

And if emissions continue at the same rate, with an increase of 5°C, two-thirds of the glaciers will have evaporated. Although formed 70 million years ago, they are extremely sensitive to climate change. Since the 1970s, a retreat and a thinning of the snow cover have already been observed. The phenomenon is aggravated by the pollution coming from the plains of India which deposit black dust on glaciersaccelerating their melting.

A billion people at risk

The report, unprecedented in its scope, required five years of work and brings together the views of 350 researchers and experts from 22 countries and 185 organizations. It highlights the severe consequences of this melting for the 250 million inhabitants of these mountains and the 1.65 billion who live in the river basins downstream. The HKH glaciers thus supply ten of the most important river networks of the worldof which the Gangesthe Indus, the Yellow, the Mekong and the Irrawaddy.

” An increase in the number and size of glacial lakes will lead to an influx of water into major rivers, which could cause flooding and crop destruction “, warns the study. The increase in debit of the Ganges and the Brahmaputra will also force changes in theagriculture. More frequent landslides and floods endanger more than a billion people », warns the Icimod.

The Alps, too, could lose 90% of their glaciers

All over the world, mountains are melting awayeye. The glaciers of the French Alps have lost 25% in 12 years and their melting is three times faster since 2003 compared to the previous period (1986-2003), according to the Laboratory of Glaciology and Environmental Geophysics (LGGE) in Grenoble. Depending on the magnitude of warming, 50 to 90% of alpine glaciers could disappear by 2100. In the Pyrenees, half of the glaciers have melted in the past 35 years and the trend seems to be accelerating. According to the latest bulletin from World Glacier Monitoring Service (WGMS), glaciers around the world lost an average of 0.9 meters of water mass equivalent per year in the years 2013-2016, compared to 0.2 meters for the decade 1981-1990.

Himalayan glaciers: the melting trend is confirmed

Article by Bruno Scla published on 06/12/2011

The International Center for Integrated Mountain Development (Icimod) published, on the sidelines of the Durban summit, a summary of the state of the glaciers in the Himalayas. Overall, they tend to melt like snow at Sun.

In ” off ” from durban summitthe International Center for Integrated Mountain Development (Heremod) published on December 4 three reports concerning the glaciersthe snow and the climate change in the Himalayas. These reports highlight in particular a significant melting of the glacierswhich could have strong repercussions on the inhabitants of the different valleys.

These publications constitute the most complete synthesis of the state of glaciers and coat snowy peaks of the Himalayas in the region ofHindu Kush-Himalayaswhich encompasses the majority of the Himalayan peaks.

Fifty-four thousand glaciers in the Himalayas

The first object of the work of this organization was to identify the glaciers of the region. They are 54,000 in number (i.e. 30% of the world total) and cover an area of ​​60,000 km² for approximately 6,000 km³ of ice. But among this accumulation of glaciers – which is why the region is called the third pole – only ten have been studied precisely, and it is on these that the synthesis of the Icimod focused.

And the results speak for themselves. Over the past thirty years, the area covered by glaciers in Bhutan has decreased by 22%, and 21% in Nepal. In addition, Icimod experts noted a significant drop in mass balance – the difference between accumulation andablation. Between the periods 1980-2000 and 1996-2005, the melting rate of glaciers has thus globally doubled, although this rate varies quite strongly depending on the area considered.

More than 1 billion inhabitants dependent on glaciers

If the Icimod report does not give any date for the disappearance of the Himalayan glaciersit nevertheless confirms a trend: the melting is accelerating.

The members of Icimod are also worried about the people who live in the valleys. The glaciers indeed feed a dozen major rivers – the Amu-Daria, the Indus, the Ganges, the Brahmaputra, the Irrawaddy, the Salouen, the Mekong, the Yangtze, the Hunag He and the Tarim – of which 1, 3 billion people depend on it. A decrease in water supply would threaten agriculture and biodiversity and could cause water stress, i.e. a greater demand for water than supply.

Hoping that these results will be heard by the negotiators on the climate gathered in Durban.