INSUBCONTINENT EXCLUSIVE:

Vegetation is expanding at high altitudes in the Himalayas, including in the Everest region, new research has shown.The researchers found

plant life in areas where vegetation was not previously known to grow.A team used satellite data from 1993 to 2018 to measure the extent of

plant cover between the tree-line and the snow-line.The results are published in the journal Global Change Biology.The study focused on the

subnival region - the area between the tree-line (the edge of the habitat at which trees are capable of growing) and the snow line (the

boundary between snow-covered land and snow-free land).Subnival plants are mainly small grasses and shrubs."The strongest trend in increased

vegetation cover was between 5,000 metres and 5,500 metres altitude," said Dr Karen Anderson, from Exeter University, lead author of the

report."At higher elevations, the expansion was strong on flatter areas while at lower levels that has been observed on steeper

slopes."Using Nasa's Landsat satellite images, the researchers divided the heights into four "brackets" between 4,150m and 6,000m.It

covered different locations in the Hindu Kush Himalayas, ranging from Myanmar in the east to Afghanistan in the west.Earlier research had

shown expansion of the tree-line at lower elevationsIn the Everest region, the study found a significant increase in vegetation in all

height brackets.Other researchers and scientists working on glaciers and water systems in the Himalayas have confirmed the expansion of

vegetation."It (the research) matches the expectations of what would happen in a warmer and wetter climate," said Prof Walter Immerzeel,

with the faculty of geosciences at Utrecht University in the Netherlands, who was not involved in the study."This is a very sensitive

altitudinal belt where the snowline is

A withdrawal of the snowline to higher altitudes in this zone provides opportunity for vegetation to grow."The extent of vegetation in 1993

(blue) vs 2017 (red), derived from Landsat data in the region around Mount EverestThe research did not examine the causes of the

change.Other research has suggested Himalayan ecosystems are highly vulnerable to climate-induced vegetation shifts."We have found the

tree-line expanding in the subalpine regions of Nepal and China as the temperature rises," said Achyut Tiwari, assistant professor with the

department of botany at Nepal's Tribhuvan University."If that is happening with trees at lower elevations, clearly the plants at higher

altitudes will also be reacting to the rise in temperature."Some scientists regularly visiting the Himalayas have confirmed this picture of

expanding vegetation."Plants are indeed colonising the areas that once were glaciated in some of these Himalayas," said Elizabeth Byers, a

vegetation ecologist who has carried out field studies in the Nepalese Himalayas for nearly 40 years."At some locations where there were

clean-ice glaciers many years ago, now there are debris-covered boulders, and on them you see mosses, lichens, and even flowers."Some

locations high up in the Himalayas have flowering plants like theseLittle is known about plants at these even-higher altitudes, as most

scientific studies have focused on retreating glaciers and expanding glacial lakes amid rising temperatures.The researchers said detailed

field studies on vegetation in the high Himalayas were required to understand how the plants interact with soils and snow."What does the

change in vegetation mean for the hydrology (the properties of water) in the region is one of the key questions," said Dr Anderson."Will

that slow down the melting of glaciers and ice sheets or will it accelerate the process?"The Hindu Kush Himalayan region extends across all

or part of eight countries, from Afghanistan in the west to Myanmar in the east

More than 1.4 billion people depend on water from this region. 1.9 billion people rely on natural 'water towers'By Jonathan Amos Women

tend their potato crop in Chipursan valley, Pakistan

The region is part of the Indus water towerIn a unique study, scientists have assessed and ranked the importance of Earth's great "water

towers". These are the 78 mountainous regions that are able to generate and then store vast quantities of water. They deliver it in a

controlled way to major populations living downstream. The Dutch-led team finds Asia's Indus basin - fed by the Himalayan, Karakoram,

Hindu-Kush, and Ladakh ranges - to be the most important storage unit on the planet. Its waters, produced at high elevation from rain and

snow, and draining from lakes and glaciers, support more than 200 million people settled across parts of Afghanistan, China, India and

Pakistan. But the Indus water tower, the researchers point out, is also the most vulnerable on their list of 78. It's subject to a range

of current and future pressures, from ever greater demand - for more drinking water, for increased irrigation and industry, etc - to issues

that could severely curtail supply

The latter will include geopolitical tensions, given the Indus intersects national boundaries; but the most obvious threat is climate change

A warming world will disrupt precipitation patterns and denude glaciers of their storage capacity. Asia's glaciers put the brakes onSpy

satellites reveal rapid Himalayan glacier melt Media captionProf Walter Immerzeel: "Our data can underpin mountain-specific policies and

water treaties""If, basically, the demand is higher but the supply decreases, then we really have a problem," said research team-member Dr

Tobias Bolch from the University of St Andrews, UK. "And this is, I think, one of the major strengths of our study - that we have looked

closely at both sides, so the supply index and the demand index," he told BBC News. Dr Bolch is speaking here at the American Geophysical

Union's Fall Meeting, the largest annual gathering of Earth scientists

His and colleagues' work is being published simultaneously in the journal Nature. Image copyrightMARK FISHER/NATIONAL GEOGRAPHICImage

captionInstalling a new weather station on Everest: The study incorporates novel data-setsThe team conducted the assessment across the major

continents, identifying what it regarded as the five most relied-upon, natural water tower systems in those regions: Asia: Indus, Tarim,

Amu Darya, Syr Darya, Ganges-BrahmaputraEurope: Rhône, Po, Rhine, Black Sea North Coast, Caspian Sea CoastNorth America: Fraser, Columbia

and Northwest United States, Pacific and Arctic Coast, Saskatchewan-Nelson, North America-ColoradoSouth America: South Chile, South

Argentina, Negro, La Puna region, North ChileAfrica does not appear in this listing, principally because it is devoid of major glacier

systems

Ice bodies do exist on the continent, in places such as on Mount Kilimanjaro and Mount Kenya, but their contribution to downstream

catchments is limited. And one of the defining aspects of the towers is the way they are able to maintain essential water supplies to

populations even in drought years through the steady melt of high-elevation ice in summer months. What's clear from the study is just how

much more vulnerable the Asian towers are compared with the rest of the world

Some of that has to do with projected future demand

Population growth in Asia will be much higher than in Europe, for instance. But in Asia, too, there are specific political stresses that

will challenge the future reliability of towers. Image copyrightMATTHEW PALEY/NATIONAL GEOGRAPHICImage captionThe Shimshal Pamir region of

Pakistan, Water from here flows through the Indus basinExamples include the Amu Darya and Syr Darya river basins

Their waters - again sourced from high-mountain glaciers - run through low-precipitation areas where there is intense competition for

irrigation for agriculture

The much reduced size of the Aral Sea, which both rivers ultimately feed, is evidence of this. "What we recommend in our study is that we

should really recognise mountains as global assets of the Earth system, and that means mountain ranges should be at the top of political

agendas, and dedicated policies should be developed," co-team leader Prof Walter Immerzeel from Utrecht University said. "We are only the

scientists; we put out the numbers

But we've got very much better at that over the past two decades, so we can give really specific scientific background that can help for

example to develop water treaties

We can aid the process." Dr Bethan Davies, a team-member from Royal Holloway, University of London, commented: "I think when we've talked

about climate change and ice loss, a lot of the narrative has been around sea-level rise

But actually over the next 100 years, climate change is going to affect drinking water for people, water for power, water for agriculture -

and in these water towers, we're talking about the supply to about 1.9 billion people

That's more than 20% of the world's population. "We need to adopt urgent mitigation strategies or we will face severe water shortages,"

she told BBC News. The water towers study was supported by National Geographic and Rolex as part of their Perpetual Planet partnership

A portal allows users to explore the data and compare tower rankings.Himalayan and other Asian glaciers put the brakes onBy Jonathan AmosBBC

Science Correspondent, Washington DC10 December 2018Share this with Facebook Share this with Messenger Share this with Twitter Share this

with Email ShareRelated TopicsAGU meeting Media captionAmaury Dehecq: "Knowing ice-flow speed allows us to better estimate glacier melt"The

glaciers that flank the Himalayas and other high mountains in Asia are moving slower over time. Scientists have analysed nearly 20 years of

satellite images to come to this conclusion. They show that the ice streams which have decelerated the most are the ones that have also

thinned the most. The research has implications for the 800 million people in the region for whom the predictable meltwater from these

glaciers is a key resource. The study is being presented at this week's American Geophysical Union (AGU) meeting in Washington DC - the

world's largest annual gathering of Earth and space scientists. How was the research done?Led by the US space agency (Nasa), the

assessment draws on one million pairs of pictures acquired by the Landsat-7 spacecraft between 2000 and 2017. Automated software was used

to track surface features on glaciers in 11 areas of High Mountain Asia, from Pamir and Hindu Kush in the West, to Nyainqêntanglha and

inner Tibet and China in the East. As the markers were observed to shift downslope, they revealed the changing speed of the ice

streams. The research team, headed by Dr Amaury Dehecq from Nasa's Jet Propulsion Laboratory, says nine of the surveyed regions show a

sustained slowdown during the study period. Nyainqêntanglha, for example, has seen a 37% reduction in speed per decade

For Spiti Lahaul, it is 34% - equivalent to about -5m/year per decade

These are glaciers that would normally move at tens of metres per year. Image copyrightF.PAUL/NASA/USGSImage captionLandsat has built

multi-decade records of glacier behaviour in AsiaWhat was the key finding?Perhaps the major revelation is that the reduction in velocity is

strongly correlated with thinning

Nyainqêntanglha's glaciers have been thinning on average by about 60cm a year; Spiti Lahaul's glaciers are losing thickness at a rate

of roughly 40cm a year. "The reason a glacier flows is because of gravity," explained Dr Dehecq

"Under its weight, the glacier slides across its bed and deforms, but as it thins it finds it more difficult to slide and deform; it's

kind of intuitive. "But until now there had been some debate as to whether other factors were influencing speed, such as the lubrication of

the bed as a result of increased meltwater getting under the glacier

Well, we show thinning is actually the dominant factor," he told BBC News. Are some glaciers getting faster?The slowdown trend is strongest

in the south and southeast of High Mountain Asia; it is less pronounced in the West. Regions like the Karakorum in Pakistan, and Kunlun

just across the border in Tibet/China, have actually shown a slight thickening over time and a marginal speed-up as a consequence. "That's

the influence of different climatic conditions," said co-author Dr Noel Gourmelen from Edinburgh University, UK

"Precipitation in the East is affected by the Asian monsoon and in the West and North-West, it is delivered by westerlies; although it's

not exactly clear why the Karakorum has been gaining mass." Image copyrightSHYLENDRAHOODEImage captionGalcier meltwaters ensure south Asia

has a consistent supply of water, even in droughtWhy is this research important?The meltwater that flows from the 90,000 glaciers in High

Mountain Asia is critical to the lives and livelihoods of the people downstream

But the significance goes much wider, because the snow and ice stored "in the freezer" at high altitude would otherwise push up global sea

levels if it all melted and ran into the ocean

That is why scientists need to understand how the glaciers will respond in an ever-warming world. This study, which has also been published

in the journal Nature Geoscience, has described an important dynamic that will moderate how much ice is transported down mountains to the

elevations where it can melt. Computer models that try to project the future resilience of the glaciers in what they call Earth's "third

pole" must now take account of this behaviour. Dr Hamish Pritchard from the British Antarctic Survey also studies these glaciers

He said their contribution to rivers across the region was small in the average year, but significantly heightened during years of

drought. "My research shows that when the summer rains fail, glacier melt comes to dominate water inputs to many catchments in India,

Nepal, Pakistan, Tajikistan and Kyrgyzstan

Without this water supply more crops would fail, substantially less hydropower would be generated and more people would be forced to

migrate," he told BBC News. "These rivers that flow down from the mountains pass through many communities and across national borders, so

when supplies are low, tensions between neighbouring communities and countries would likely increase. "Studies show that this tension could

lead to conflict, with implications far beyond South and Central Asia. "The key role of these glaciers then is as a buffer against the

worst effects of drought, and so the loss of glacier ice can be seen as a threat to the future stability of the region."Spy satellites

reveal extent of Himalayan glacier lossBy Rebecca MorelleScience Correspondent, BBC News19 June 2019Share this with Facebook Share this with

Messenger Share this with Twitter Share this with Email ShareRelated TopicsCold WarImage copyrightNRO/USGSImage captionThe Hexagon images

were declassified in 2011 and digitised for scientific studyImages from Cold War spy satellites have revealed the dramatic extent of ice

loss in the Himalayan glaciers. Scientists compared photographs taken by a US reconnaissance programme with recent spacecraft observations

and found that melting in the region has doubled over the last 40 years. The study shows that since 2000, glaciers heights have been

shrinking by an average of 0.5m per year. The researchers say that climate change is the main cause. "From this study, we really see the

clearest picture yet of how Himalayan glaciers have changed," Joshua Maurer, from Columbia University's Lamont-Doherty Earth Observatory

in New York, told BBC News. The research is published in the journal Science Advances. Asia's glaciers put the brakes onWarming

threatens Himalayan glaciersMelting glaciers reveal Everest bodiesImage copyrightNROImage captionThe Hexagon satellites were a top secret

American reconnaissance programmeDuring the 1970s and 1980s, a US spy programme - codenamed Hexagon - launched 20 satellites into orbit to

secretly photograph the Earth. The covert images were taken on rolls of film that were then dropped by the satellites into the atmosphere

to be collected mid-air by passing military planes. The material was declassified in 2011, and has been digitised by the US Geological

Survey for scientists to use. Among the spy photos are the Himalayas - an area for which historical data is scarce. By comparing these

pictures with more recent satellite data from Nasa and the Japanese space agency (Jaxa), the researchers have been able to see how the

region has changed. The Columbia University team looked at 650 glaciers in the Himalayas spanning 2,000km. The group found that between

1975 and 2000, an average of 4bn tonnes of ice was being lost each year. But between 2000 and 2016, the glaciers melted approximately twice

as fast - losing about 8bn tonnes of ice each year on average. Image copyrightNASAImage captionWe now have a satellite record approaching

nearly 50 years in lengthMr Maurer said: "For a sense of scale, 8bn tonnes of ice is enough to fill 3.2 million Olympic-sized swimming pools

per year." And the ice loss was not uniform, he added. "Glaciers lose most of their ice in the lower elevation portions of the glacier,

and it's there where most of the thinning is concentrated. "Some of those zones have been thinning by as much as 5m per year." Among the

scientific community, there has been some debate over the cause

Changes in rainfall in the region and soot deposited from industrial pollutants are thought to have hastened the melt. However the Columbia

team said that while these factors were contributing, rising temperatures in the Himalayas were the main cause. "The fact we see such a

similar spatial pattern of ice loss across so many glaciers across such a large and climatically complex region suggests there needs to be

some kind of overall forcing affecting all of the glaciers similarly." The Hexagon photographs would come down in a capsule from the

satellitesScientists say continued losses will have a huge impact. In the short-term, the huge increase in meltwater could cause

flooding. In the longer term, millions of people in the region who depend on glacier meltwater during drought years could experience very

real difficulties. Commenting on the research, Dr Hamish Pritchard from the British Antarctic Survey, said: "What's new here is being

able to see how the melting of glaciers across the whole Himalayan range has increased due to climate change. "Over one generation, the

melt has doubled and these glaciers are now shrinking fast. "Why does this matter? Because when the ice runs out, some of Asia's most

important rivers will lose a water supply that keeps them flowing through drought summers, just when water is at its most

valuable. "Without mountain glaciers, droughts will be worse for millions of water-stressed people living downstream." Himalayan and other

Asian glaciers put the brakes onBy Jonathan AmosBBC Science Correspondent, Washington DC10 December 2018Share this with Facebook Share this

with Messenger Share this with Twitter Share this with Email ShareRelated TopicsAGU meeting Media captionAmaury Dehecq: "Knowing ice-flow

speed allows us to better estimate glacier melt"The glaciers that flank the Himalayas and other high mountains in Asia are moving slower

over time. Scientists have analysed nearly 20 years of satellite images to come to this conclusion. They show that the ice streams which

have decelerated the most are the ones that have also thinned the most. The research has implications for the 800 million people in the

region for whom the predictable meltwater from these glaciers is a key resource. The study is being presented at this week's American

Geophysical Union (AGU) meeting in Washington DC - the world's largest annual gathering of Earth and space scientists. How was the

research done?Led by the US space agency (Nasa), the assessment draws on one million pairs of pictures acquired by the Landsat-7 spacecraft

between 2000 and 2017. Automated software was used to track surface features on glaciers in 11 areas of High Mountain Asia, from Pamir and

Hindu Kush in the West, to Nyainqêntanglha and inner Tibet and China in the East. As the markers were observed to shift downslope, they

revealed the changing speed of the ice streams. The research team, headed by Dr Amaury Dehecq from Nasa's Jet Propulsion Laboratory, says

nine of the surveyed regions show a sustained slowdown during the study period. Nyainqêntanglha, for example, has seen a 37% reduction in

speed per decade