They're just so powerful,” Lisa McKeon said of the images. “They're a great way to put a recognizable face on climate change.”
To be sure, the impact is visceral, intuitive, obvious, absolutely unambiguous - in short, everything that science tends not to be.
Yet McKeon is a scientist, a physical scientist to be exact, working with the U.S. Geological Survey. She's part of a team, based in Glacier National Park, studying the effects of climate change on mountain ecosystems.
These aren't predictions of things to come, mind you. These are measurable effects that are already taking place - that have been taking place for years.
Streamflows have changed, as have water temperatures. Vegetation has changed, biology has changed, habitat has changed.
She can prove it to you with graphs and charts and statistics, with carefully measured numbers and with cutting-edge computer models.
Or, she can show you her pictures.
“They're like springboards into more detailed discussions,” McKeon said.
MORE PHOTOS OF MELT
Picture this: a grainy black-and-white, taken by T.J. Hileman back in 1938 from atop Mount Gould. Below sprawls Grinnell Glacier, its dirty ice grinding away, slowly scooping a cirque from high on the steep eastern flank of the Continental Divide. The floe reaches as far as the eye can see.
Now picture this: a shiny color photograph taken from the exact same spot in 1981. Grinnell's icy glacial cap is withered and melted away, vast reaches of rock exposed for the first time in who knows how long. Below, a deep meltwater lake has formed, milky with glacial till and spotted with ice born of Grinnell's shrinking mass.
You don't need to know much about atmospheric chemistry or ultraviolet light or global climate patterns to get the idea. Glacier's glaciers are melting. There it is, right smack in front of you, in black and white - and color, too.
“People really connect when they see the pictures,” McKeon said. “They just get it, right away.”
And once they've got it, she said, they're often eager to learn more, to learn what empirical data have to say about the reality behind the repeat photography.
That's what McKeon calls her work - “repeat photography.” She started back in 1997, when a longtime Glacier Park employee dropped an old-time photo on her desk.
In that 1923 shot, Boulder Glacier's massive ice cave looms large, a vast expanse of icy white commanding the entire frame. A full 56 years later, Jerry DeSanto - the same fellow who gave McKeon the photos - shot another image from precisely the same spot, with nary a hint of white to suggest a glacier had ever been there.
View them side by side and the effect is unsettling, to say the least.
“We thought, ‘Oh, this would be great to do more of,' ” McKeon said.
The timing was right. Al Gore, then vice president, had a trip to Glacier Park planned for the fall of 1997 to talk specifically about global climate change. What better way to illustrate the message than with images such as these?
So McKeon started digging, and soon had a handful of historic photographs selected from the park's archives. Then she and others hit the trail, packing cameras and tripods and global positioning systems, looking to reproduce the images of old.
“It could take us hours and hours to find the exact spot” where the historic shutter had been snapped, she said. “We thought it was just going to be a piece of cake, but it wasn't.”
Many of the images were taken off-trail, on high mountain routes traveled only by mountain goats and a very few early alpinists. In some spots, brush and krummoltz choked the way, a tangle fueled by an intervening century of fire suppression.
One day, bushwhacking above Grinnell Glacier, McKeon stumbled onto a long-abandoned trail.
“That was exactly the spot,” she said. “It was really cool, a perfect match. It was fun to imagine that you were in the same spot as a photographer 100 years ago.”
She worked fast. She had to. Her project leader, USGS research ecologist Dan Fagre, estimates that if current climate trends continue, Glacier's glaciers will be completely melted away in a short 25 years - by the year 2030.
Fagre has been meticulously studying glacial mass and depth, the rate of retreat. He's been using satellites and computer models and fancy 3-D imaging to determine how the mountain ecosystem will change as the ice fades.
His is not the stuff of academic obscurity. A full fifth of the terrestrial world is covered by mountains. And a whopping half of all the world's drinking water comes from those high reaches, not to mention water for agriculture, fisheries and industry.
Understanding how those systems are changing, then, is very serious business. Fagre's tapped into chemistry and forestry in his work, biology and hydrology and ecology, glaciology, meteorology, physics, computer science, mathematics.
And no matter which perspective he tells the story from, the narrative remains the same: It's getting warmer faster; the ice is melting at an unprecedented rate.
All the hottest years on record have come in the last decade. Studies of corals and ancient tree rings suggest these are the hottest times in more than a millennia, as far back as we can reliably look.
And Glacier's glaciers, it turns out, are perfectly poised to provide a sort of “canary in the coal mine” early warning system.
They're remote, and so they're not overly impacted by any immediate human presence. They're cold, so they react quickly to heat. They're old and slow, and so they tend to reflect big changes instead of seasonal fluctuations. And they're accessible, with permanent ice pack at elevations as low as Bozeman's.
Those, in fact, are exactly the reasons Gore picked Glacier Park for his stump back in 1997. The change here is easy to see.
In 1850, when early European explorers first began documenting what's now Glacier National Park, there were an estimated 150 glaciers draping the limestone peaks. By the early 1960s, when the first complete aerial survey was undertaken, there were 50. By 1998, when that survey was repeated, there were 26, all mere remnants of once huge ice floes that dated back 12,000 years to the Pleistocene.
In 1850,100 square kilometers of glacial ice covered the park. In 1966, it had been more than halved to just 40 square kilometers. By 1998, it had been halved again, to 19 square kilometers.
Meadows are creeping uphill, as are trees and other vegetation. Habitats are shifting, water temperatures are increasing, fires are raging. What happens, Fagre wonders, when the glaciers that have long provided summer meltwater are gone, replaced by trees that suck up whatever water's available?
It's a complete reversal of the system, this swap of roots for ice, and scientists tell us it's bound to have downstream consequences.
The numbers tell the story: In 1850, Agassiz Glacier covered more than 4 square kilometers. By 1993, it covered just one and was broken into 10 separate ice patches.
And now the retreat is accelerating.
From 1850 through 1911, Agassiz melted at a rate of about 7 meters per year. But from 1911 through 1926, the ice retreated upward of 42 meters per year. Since 1932, the melt has exceeded 117 meters per year.
But those are just numbers, abstractions impossible to truly wrap your brain around. To make it real, you need McKeon's striking series of four photos - an original and three repeats - taken of Grinnell Glacier from atop Mount Gould.
There's that icy old Hileman shot, of course, and that dramatic 1981 image complete with the newborn lake.
But most interesting are the two that follow.
McKeon's boss, Fagre, repeated the images in 1998, proving you don't have to look back a century to see big change.
Look close, and the lake has obviously grown during the 1980s and 1990s, and the ice has quite visibly shrunk. It's striking, this glacial retreat in one young man's lifetime.
But then comes the real shocker. A fourth photo, taken in 2005, shows clearly the remarkable melt since 1998, a tremendous geologic vanishing act in a scant seven years.
“We're working fast,” McKeon said, “to photo-document the park's glacier's before they're gone.”
That's no easy task. First, she has to find the old photos from amid the jumbled archive. Then, she has to find the exact site from which to repeat the shot, the exact angle and the exact conditions. Her window is narrow - she has to shoot after last spring's snow has melted, but before next fall's arrives. She has to shoot when the sun is out, when there's no wildfire smoke, when the air is crisp and clean.
It helps if the historic photo has a permanent foreground, a boulder, say, or a distinctive cliff face.
“It can take a while,” McKeon said in her understated way.
But it's worth it. Not only do the repeat photographs document retreating ice, they also show the disappearance of Glacier's white bark pine trees, the effects of disease and fire and avalanche, the migration of vegetation up the mountainsides as weather warms.
They are, McKeon said, an immediate and in-your-face pad for launching into any number of scientific inquiries. And they are, without a doubt, testament to the dynamic nature of nature, evidence that only change is forever.
“I think the images we're taking are going to be really important to the park,” McKeon said, just as those snapped by Hileman and others are now. “It's a real document of change.”
So far, they've repeated 60 pictures of 17 glaciers, and are trekking still farther into the backcountry to shoot some of the park's more inaccessible alpine ice.
The photos aren't exactly scientific, she admits, in the way of Fagre's other high-tech research tools, but they are powerful, immediate, accessible and understandable to any and all.
“People really respond to the sets,” McKeon said. “And for me, it's been fun to be part of something that's a piece of Glacier's history.”
And, of course, its future - the day not so far away when the ancient ice will be no more.
Reporter Michael Jamison can be reached at 1-800-366-7186 or at mjamison@missoulian.com.
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