Below is a photo of the Pasterze Glacier, a mass of ancient ice that weaves 5 miles through the Austrian Alps. But it's not just any photo — it's an 85-megapixel über-photo by photographer André van der Hoeven, who converted it to "deep zoom" format with Microsoft's Zoom.it. Use the buttons at bottom-right or scroll with your mouse to zoom in and out, and click/drag on the image to move around:
(Note: Zoom.it appears to have technical issues in some browsers. If you don't see the glacier photo directly above this paragraph, try refreshing the page.)
While this looks like a seamless single image, van der Hoeven made it by stitching together 60 different photos he took during a recent trip to Pasterze. And as he explains on Flickr, this isn't even the biggest version — the original mosaic was a whopping 185 megapixels, but he reduced it to 85 megapixels for Web use.
To fully appreciate the enormity of this scene, zoom in toward the lower-left corner, near the blue chunks of crumbling ice and the flow of meltwater. Then look to the right, where several people are visible standing around the banks of the meltwater stream. Slowly zoom back out as you keep an eye on them (h/t Phil Plait).
As big as Pasterze is, though, it's been receding for decades amid rising summer temperatures and waning winter snowfall, losing about 50 feet of ice per year. That's a common plight for many of the planet's roughly 160,000 glaciers, which scientists monitor for shrinkage by studying 37 "reference glaciers" from various regions and elevations around the world. According to the most recent survey by the World Glacier Monitoring Service, each of these glaciers lost an average 676 water-equivalent millimeters (mmWE) in the 2008-'09 glacial year, up from 503 mmWE in '07-'08.
On a longer time scale, WGMS reference glaciers lost an average 667 mmWE per year between 2000 and 2009, compared with 437 mmWE per year in the 1990s and 222 mmWE per year in the '80s. Researchers acknowledge that some glaciers are stable or even growing, mainly those at high elevations — as U.S. Geological Survey glaciologist Bruce Molnia told MNN in 2010, "The higher you go, the less change you see." Overall, however, the outlook for Earth's glaciers is not good.
"The melt rate and cumulative loss in glacier thickness continues to be extraordinary," the WGMS concluded in its 2011 report. "Furthermore, the analyses ... show that the glaciers are in strong and increasing imbalance with the climate and, hence, will continue to melt even without further warming." More warming is widely expected, though, and may thus pose a snowballing threat to glaciers worldwide.
The Alps are a notable hotspot for this trend, and not just because of France's Sarennes Glacier, which led all reference glaciers in '09 and '08 with losses of 3,900 and 2,340 mmWE, respectively. It has lots of company across the region, such as the nine Austrian glaciers (including Pasterze) shown in this WGMS chart:
See the full WGMS report for data and trends in other areas. To compare before/after photos of melting glaciers in the U.S., check out this interactive collection of old photos alongside recent shots from similar angles. And for a more cinematic look at the issue, National Geographic photographer James Balog will release a new documentary in November, "Chasing Ice," that he's been working on since 2005.
According to the film's website, Balog used "revolutionary time-lapse cameras ... to capture a multi-year record of the world's changing glaciers," resulting in dramatic videos that "compress years into seconds and capture ancient mountains of ice in motion as they disappear at a breathtaking rate." Here's the trailer:
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