From a Recent Alaska Cruise-Glaciers

Glaciers advancing and receding are a part of history - And it appears that not much is different now. From the readings and observations of explorers George Vancouver, John Muir, Captain Cook, and Charles Wood the first observed glacial front in what is now Glacier Bay National Park was in 1770, and since then the glaciers steadily receded – 60 miles by 1860.The glacier in what is now the main inlet receded another 25 miles by 1879. The literature documenting the mileposts, including maps from the National Park Service, suggests that these glaciers have been receding steadily since the end of the Little Ice Age, which is not a definite date but generally around the time of or after the revolutionary war.
Cruise ships can and do go up close only to the glaciers that end at the water (by the way it’s tough for such glaciers to “advance”) and the most awesome was the Margerie glacier. It is a couple miles wide at the face and over 200 feet tall all the way across. From Deck 14 which is about 100 feet above the water we were overshadowed by the face of the glacier. I had read about and waited for “calving” – when a front piece of the glacier breaks off and falls. It happens in an instant with a little snow falling, then a chunk of ice, then a resounding crack and a thunderous echo across the inlet. The calving we saw looked small but was probably the size of a large truck.
Another glacier area is the Juneau ice field, a 1500 square mile area at an average elevation of 5000 feet above sea level, which feeds 39 glaciers. One of the smallest but easily accessible to man is the Mendenhall Glacier, which is also receding. All of the receding glaciers are small and have a smaller portion of ice field source feeding them. The Juneau ice field which feeds the largest glacier of all 39 – the Taku Glacier, is rapidly advancing, but inaccessible to tourists. The Taku glacier appears on charts as large as all the other 38 ice field’s glaciers. The glaciers move forward as much as 6 feet/day, but melting and “calving” exceeds the advance when a glacier recedes. The Juneau ice field which feeds these glaciers gets as much as 100 feet of snow/year, and climatologists say (per the Forest Service) that warmer climate may actually increase the snowfall amount on the ice field. The effect of increased snowfall on whether a glacier will (net) advance may not be known for 25-50 years.Juneau itself is so isolated by very steep rocky mountains that no road could be built in or out; the town of 30,000 is only accessible by float plane and boat and barges. Electricity is generated by hydroelectric plants, supplemented by diesel generators when avalanches take out main power lines in the winter. I could not easily enough find the historical average temperatures for Juneau, but I am told that they have been increasing over the past 100 years. No one – rangers nor the book – could explain why the largest glacier is still advancing while most of the 38 small glaciers are receding in the Juneau ice field. And no one could reconcile the advancing glaciers with global warming, nor why man’s effect on the climate would explain receding glaciers over 200 years ago.
Tongass National Forest is part of the Forest Service Department of Agriculture, while the Glacier Bay National Park is part of the Park Service Department of Interior. Both departments’ literatures admit the glaciers have advanced and receded through recorded history, but recently added the phrase: “..in part due to the effect of man on the environment.” The rangers made it clear that this was an “official” position of the government, and were uncomfortable talking about the advancing glaciers. The book that I read on these glacial areas was not written by the government and did not appear to have any political motive. My interest in all of this was focused on Alaskan climate and the glacial areas that we visited. It is clear that we are in a changing world, and to me Mother Nature has more impact on man with volcanoes, earthquakes, and solar radiation than man does on the Mother Nature. All you need to do is see the massive wilderness and even the smallest glaciers to see how tiny we are in relation to the earth (even cumulatively), and then read the documentation as it was logged by explorers and historians.