I’ve seen and walked on small glaciers in the Sierra–in late summer I’ve seen the bare ice under my cramponed boots and watched meltwater flow in shallow channels. I’ve peered into their bergschrunds where the ice has pulled away from their headwalls.
But compared to the valley glaciers in cooler, wetter mountains in Alaska and the Alps, these are mere remnants surviving in the shade of tall rock walls. Also, my experiences with them have been snapshots of what they were that year. I’ve spent time in Yosemite Valley and marveled at still-visible glacial polish in the high country, but I haven’t had the experiences of those great glaciers as they did their work.
I read of receding glaciers in the world’s mountains and portions of ice shelves breaking off in the antarctic as the climate warms, and I think I understand their implications. But to really appreciate this personally, I had to personally walk beside living valley glaciers and see what’s been happening to them recently.
In November 2011 I got that chance in New Zealand’s Southern Alps.
Where moistere-laden storms from the Tasman Sea hit the abrupt west face of the Southern Alps, ice fields form and flow downward toward the sea. The Franz Josef Glacier flows down a steep trough to a flat outwash plain only a few miles from the shore. A trail leads less than a mile to its foot.
At a vantage point just above the outwash are large interpretive signs. Along with explanatory text, one sign features a photograph of the glacier from a low hill to the left of the trail. Labeled lines on the picture show the level of the ice during historic times beginning in 1865. The picture itself, apparently taken around the beginning of the 2000s judging from the text below, shows the glacier much thicker and ending closer to the road than was the case when I saw it in person. It had shrunk dramatically in only a few years.
Go to the gallery above and click the photo of the sign, on the left. Scroll down and click the “View full size” icon. Then when the slightly larger image displays, position the small “+” icon on the part of the photo you want to see close-up and click. Now you’re in the full 4000 x 3000 pixel picture. Move around in it using the scroll bars at the side and bottom.
The next week we drove around to the Tasman Glacier below towering Mt. Cook. Standing on a windswept moraine we looked 90 meters (300 feet) down to a large lake trapped by the downstream loop of the moraine. Icebergs floated far below. Over three kilometers up the lake was a low wall of ice at the calving face of the glacier. The glacier itself was completely covered by rocks which had rolled down from the steep slopes or melted out of the ice. The amount by which the glacier had shrunk in a relatively short time was shocking. If we had been here a hundred years ago we would have had to climb up onto the ice. For pictures and a description go to this post.
The next day we gazed on the Hooker and Mueller Glaciers in their valleys below mountain walls clothed by hanging glaciers and icefalls. Here we saw the same thing: thinning, receding glaciers covered by debris, calving into lakes held back by recent moraines. This post describes the scene.
In 1913, meltwater from the Mueller Glacier breached the side of its moraine and destroyed buildings of The Hermitage resort a mile down the valley. The point where the water overflowed the moraine is now three hundred feet above the meltwater lake.
This January I saw “Chasing Ice,” the documentary movie of James Balog’s Extreme Ice Survey http://extremeicesurvey.org/ . This dedicated photographer and his team have secured time-lapse digital cameras above the ends of glaciers around the world to document their shrinkage over a period of years. When viewed as movies within the movie, the rapid retreat and thinning of glaciers before our eyes is sobering.
the movie takes us with the crew as they explore a large glacier in Greenland. Finding a deep gorge cut into the ice by a river of meltwater, they follow it downstream until the river plunges into an abyss, disappearing vertically into the darkness toward the glacier’s base. Awesome–but that glacier, too, is shrinking fast.
Glaciers and their dynamics are things of beauty and awe, as well as sources and storehouses of precious fresh water. Rapid global warming, hastened by modern society’s emissions of greenhouse gases, is threatening them and the societies that depend on them for agriculture and drinking water.
Worldwide and locally, transportation, energy production and other activities must be made more efficient and cleaner in relation to greenhouse gas emissions. Renewable energy sources are coming on strong, and energy-saving retrofitting of buildings is becoming widespread. The good news is that, as part of the grand world which we inhabit, we are each empowered to help make this happen! If not already involved, join with your local group of the Sierra Club or other environmental organization.