Environment

Declassified spy satellite photos reveal accelerating ice loss at Earth's "third pole"

Declassified spy satellite pho...
Recently declassified US spy satellite images reveal Himalayan glaciers have been melting at an accelerating rate
Recently declassified US spy satellite images reveal Himalayan glaciers have been melting at an accelerating rate
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These radar images show the rate of ice gain and loss in Jakobshavn Glacier in Greenland since 2016
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These radar images show the rate of ice gain and loss in Jakobshavn Glacier in Greenland since 2016
Declassified spy satellite photos of the Himalayas, like this one taken in 1975, were used in a new study to find rates of ice melt over the last 40 years
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Declassified spy satellite photos of the Himalayas, like this one taken in 1975, were used in a new study to find rates of ice melt over the last 40 years
Recently declassified US spy satellite images reveal Himalayan glaciers have been melting at an accelerating rate
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Recently declassified US spy satellite images reveal Himalayan glaciers have been melting at an accelerating rate

It's not entirely news that the Earth's ice budget is under threat from a warming climate, but a new study has looked into just how fast that's happening. Using recently declassified spy satellite photos, researchers found that compared to the last quarter of the 20th century, Himalayan glaciers have been melting twice as fast this century. In a rare piece of good news, a separate study has shown that a Greenland glacier has gained ice for the third year in a row.

While the Arctic and Antarctic are home to the majority of our planet's ice, the Himalayan region is hoarding some 600 billion tons of its own, giving it the occasional moniker of Earth's "Third Pole." Of course, that makes it quite vulnerable in our warming world, and plenty of studies have tried to measure just how much ice is lost every year.

To get a clearer picture of the changes in ice over the last few decades, a research team led by Columbia University has now analyzed satellite data gathered over 40 years, of some 650 glaciers spanning India, China, Nepal and Bhutan.

The older images were actually taken by US spy satellites in the 1970s and 80s, and have only been recently declassified. The researchers developed a way to build 3D models of the mountains in the images by comparing overlapping photos of the same areas and mapping the slight differences between them.

With those 3D models the researchers could measure the changes in elevation of the ice, while other images can help highlight changes in the area of the glaciers. This data was then compared to newer shots from more sophisticated satellites, which are able to directly measure elevation changes. Using both sets of data, the team compared the periods of 1975 to 2000, and 2000 to now.

The difference is stark. Since 2000, Himalayan ice appears to have been melting at twice the average rate of the previous 25 years. Between 1975 and 2000, the average loss of glacial ice was about 25 cm (10 in) per year, but this doubled to 50 cm (20 in) in the 21st century. These are average figures, spread out across the region, and in the worst-hit areas, that ice loss is as much as 5 m (16 ft) a year.

The main driver of this accelerated ice loss seems to be warming air temperatures. The researchers investigated this by collecting data from ground stations, then calculating how much melting would be expected at different times based on those figures. Sure enough, the numbers matched what was observed. That said, other factors play their part, like changes in snowfall and increased fossil fuel burning in Asia, which leaves more soot lining the glaciers. That in turn absorbs more heat from sunlight and speeds up the melting process.

"This is the clearest picture yet of how fast Himalayan glaciers are melting over this time interval, and why," says Joshua Maurer, lead author of the study.

These radar images show the rate of ice gain and loss in Jakobshavn Glacier in Greenland since 2016
These radar images show the rate of ice gain and loss in Jakobshavn Glacier in Greenland since 2016

It's not all bad news though – in a separate study, a NASA team has found a glacier in Greenland that's growing. As part of the Oceans Melting Greenland (OMG) mission, the researchers studied radar images of Jakobshavn Glacier taken over the last few years.

The study showed that this glacier, which has been shrinking for most of the last 20-odd years, has now added extra ice for the third year in a row. Between 2016 and 2019, Jakobshavn has grown by between 20 and 30 m (65.6 and 98.4 ft) each year.

But before people start declaring the climate change emergency over, there are a few caveats to consider. Unfortunately, this isn't expected to last very long – the team says this is part of a known climate pattern that's due to flip again soon. On top of that, it's not even really offsetting its own melting. Although it's growing on the surface, NASA says the glacier is still melting from below at a faster rate than it's adding new ice.

The Himalayas research was published in the journal Science Advances.

Sources: Columbia University, NASA

11 comments
RobWoods
Won't this still be better for Canada, as we can soon start experiencing longer warmer seasons, which most other countries have, and is considered more normal?
Robert in Vancouver
There's only one globe so if it was warming the whole thing would get warmer over time and all glaciers would be melting, not just some. But the warming and cooling keeps moving from one part of the globe to another so over time it balances out. In the 1970's they told us there would be another ice age unless we paid extra taxes to prevent it. Now it's all about paying extra taxes to prevent global warming.
Kitzbuhel
Panic..Panic..Panic Enough with this leftist BS. Everything changes, weather changes. Climate changes drastically as a rule. Ice ages across the continents, tropical climates far far north and south. Oceans existed where once great deserts are now. Giant mountains rose from sea level. Stop already with the leftist, panicky, rip-off oriented BS.
jetserf
@robo Excellent points. If burning carbon based fuels was such an immediate threat politicians would ban them and/or offer incentives to pursue alternative energy sources to rather than tax them.
ljaques
That's right, folks. When one glacier loses ice, another one somewhere else gets it. This is common knowledge everywhere on the planet. Well, except in Global Warming/Climate Change/Tipping Point School. Look at Googles time lapse photos of all the glaciers. It proves my point. Also, consider thermodynamics: The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system.
Mr T
Robo, no, the planet is too large for it to be that simple, thermal systems are extremely complex. http://www.pik-potsdam.de/~stefan/thc_fact_sheet.html gives you an idea of just the ocean circulation systems but it is far, far more complex than that. Jetserf, I hope you were being sarcastic, no-one could be that naive, politicians do whatever keeps them in power for the next election cycle, which means telling the public what they want to hear. But it also means pandering to their primary sponsors, and in the US and many other countries, that's the fossil fuel industry. In short, the big, dirty corporations own many of the politicians, so fossil fuels will never be banned outright by those corrupt pollies. This is the case in the US and most definitely here in Australia. I don't know why so many armchair experts think that their uneducated, ignorant opinions on climate change have more value that the vast collection of data, collected over decades by experts in the field. Are the climate deniers so egotistical that they think that their opinions actually trump facts? I guess they are, because I see the same stupid comments from the same stupid commenters here all the time, and on many other sites as well.
Ran Xerox
A glacier retreated in the Alps, know what they found? A Bronze age mine and settlement. In other words, the glacier had not been there when that mine was being worked. We are in a inter-glacial period which is punctuated with dramatic up and down swings in temp trends. Going back to hundreds of thousands of years, this period looks very much like past periods, nothing anomalous.
CAVUMark
I take a simple approach... would you rather breath the air in a Canadian forest or downtown LA? Now which should we strive towards?
Kpar
"In a rare piece of good news, a separate study has shown that a Greenland glacier has gained ice for the third year in a row." For another piece of good news, try this: the US Parks Service has removed the signs in Glacier National Park (MT) that claim the glaciers will be gone by 2020. They now leave the time frame unstated, as there has been a huge increase in the size and extent of the glaciers in the last few years. And the snow in the Northern Rockies recently? How about 18 INCHES IN JUNE?!!! (What's that? Don't you know the difference between climate and weather? Yes, I do, do you?)
WagTheSchmoo
I'm not a believer in global warming, but I have seen for myself the melting of major glaciers in Europe between '89 and now. The huge Bossons glacier near Chamonix, France was almost down to the ground in '89 and is now almost gone from view. The large glacier north of Chamonix lying atop the mountain plateau in '89 was deep and white. For some years now it has been black with SOOT (China?) and has melted to the point of almost disappearing. The same is true of a large glacier above Zermatt, Switzerland alongside the Gornergrat peak at 11,000'. A cog train goes from Zermatt to Gornergrat, where there's a large restaurant and where often in summer there is still ice and snow. Pals and I would take our bikes on the train and then ride back down to Zermatt, taking many side trips along the way ... an incredible ride. We noticed the last time we rode (in '07) that the huge glacier that had been so white and deep was now black (again with SOOT) and almost GONE! Sad indeed. In Grindelwald, Switzerland, the Upper Glacier in '89 was down to the ground and deep enough that a tunnel was formed in it with "ice rooms" containing ice sculptures, the whole thing lit by the beautiful blue light coming from sunlight through the ice ceiling. For years now that glacier has melted progressively until by 2004 if not earlier, it was no longer visible from the ground. So a 900' or so wooden staircase was built that clings to the steep mountainside to take you to the plateau where the remnants of the glacier still exist. I haven't been there since 2007, so that may be gone now too. Other than Chinese (and other's) coal soot, I can't imagine what's going on here. It's possible that most of it is just due to natural changes in earth's weather system along with some obvious soot-caused changes. The only other reason I can think of is man-made weather weaponry being used. We know it has existed for decades now, but to what extent any weather changes are due to it is a mystery to all but a few.