Five top scientists have been traveling around Alaska with five evangelical Christian leaders this week, inspecting signs of climate change and talking to Alaskans who live on the front lines of Arctic warming.
There’s been coverage in the Anchorage Daily News, the Harvard Medical School PR machine and the Associated Press. Organized by Center for Health and the Global Environment at Harvard Medical School (HMS) and the National Association of Evangelicals (NAE), the contingent visited the coastal village Shishmaref, held press conferences in Anchorage and Portage, spent time pondering the retreat of several Southcentral Alaska glaciers.
There’s good news here and, unfortunately, one of those climate change media goofs that so delights the deniers, liars and Far Right nimnos.
First the good. The people of Shishmaref, located on a sandy barrier island facing the Chukchi Sea, may be more threatened by Arctic climate change than any other Far North residents. Late forming sea ice leaves their community vulnerable to the surf and surge of fall storms, bringing waves that undercut banks, unbury already warmed permafrost, and ultimately consume land, houses and roads.
The record meltdown of Arctic ice this summer has now exposed Shishmaref and other barrier island villages like Kivalina to an unprecedented hazard come fall, with an extraordinary fetch of open water that will take a long time to freeze solid. Check out these photos from a particularly damaging storm in 2004.
So international attention gets properly focused on Alaska Native villages edging toward another fall erosion disaster.
But there’s a dark side to this publicity, one that could feed climate denier fodder.
The group of 10 spent time on Portage Lake, where one of Alaska’s most viewed glaciers has retreated across about three miles of deep water and tucked itself out of sight behind a mountain, boosting the lake’s tour boat operation and baffling tourists expecting to find a wall of ice beyond the plate glass windows at the Begich, Boggs Visitor Center.
One of the most common questions to naturalists: What happened to the glacier?
The AP played this angle up in a story zipped all over:
On Wednesday, 10 scientists and evangelicals toured the National Forest Service’s Begich Boggs Visitors Center, constructed about 50 miles (80 kilometers) south of Anchorage in 1986. Federal officials hoped it would offer protected views of Portage Glacier until 2020. But like other rivers of ice affected by warming, Portage Glacier has retreated.
Not to be overly cranky in the face of such a teachable moment, but one must ask:
Is the shrinkage of Portage Glacier really evidence of recent global warming?
Almost certainly not.
Most tidewater and lake-bound glaciers will retreat once their face gets undercut by deep water — regardless of the air temperature and melt rate. Even if a new-fangled ice age had commenced decades ago, Portage Glacier would have retreated just as far.
In fact, the face of Portage Glacier stopped retreating about seven years ago and hasn’t moved much, if at all, since 1999.
Let’s go over this startling fact again: Portage Glacier appears to have stabilized during the warmest years of the global warming juggernaut. The glacier could even begin to advance, geologists say.
This isn’t the first time that national media (and various PR types) have displayed photos of Alaska’s retreating ocean and lake glaciers as exhibit A in their proof-of-global-warming arguments. Check out perhaps the most idiotic story in climate change media history — The Race to Alaska Before it Melts — courtesy of the New York Times.
Most of these stories ignore the few glaciers that are now advancing, like the Meares Glacier in Prince William Sound. (Which, incidentally, is not a sign of climate cooling.)
Ironically, the shrinkage of mountain glaciers, and stranded coastal glaciers, offer gobs of vivid evidence that climate has undergone dramatic warming. The group planned to visit Exit Glacier, an outfall from the Harding Ice Field, and a legitimate example of how certain glaciers waste in the face of higher temperatures.
But it’s not the coastal glaciers. And it’s not Portage. These puppies wax and wane in a complex process that’s not directly connected to global warming — a calculus depending upon the amount of snow that falls up high in winter and spring, the amount of snow and ice that melts down low in summer, lubricating conditions on the bed of the glacier, and the volume of ice that gets calved into the ocean.
Think of them as gigantic conveyor belts. A retreating glacier could be actually be increasing in total volume — given a large increase in snowfall — yet transporting its excess ice into the sea as bergs and bits.
At the same time, an advancing tongue of ice could paradoxically be shrinking away in total volume, as it draws down its reserves in the mountain ice fields in order to push its stable face ahead.
A Century of Retreat at Portage Glacier, South-Central Alaska, published by the U.S. Geological Survey, applies these principles to Portage:
Like other glaciers that terminate in water, such as Columbia Glacier near Valdez or Mendenhall Glacier near Juneau, Portage Glacier has experienced accelerated retreats in recent decades that likely were initially triggered by climate change begun at the end of the Little Ice Age in the mid-1800s and subsequently controlled in recent history primarily by calving of the glacier terminus. …
By late 1999, Portage Glacier had receded almost 5 kilometers, to a more stable position at the eastern end of Portage Lake. The retreat was driven primarily by calving of unstable ice at the glacier terminus into Portage Lake.
Ice loss resulting from increased melting of the glacier surface during the past century-long general warming trend contributed to glacier retreat, but to a lesser extent. Today, the terminus of Portage Glacier remains close to its 1999 location….
Future changes of the terminus of Portage Glacier will depend on a variety of factors. However, present scientific theory … suggests that calving glaciers cycle between advance and retreat patterns; with rapid retreats, followed by stable retracted positions, slow advances, and then stable extended positions that are not directly related to climate change.
Thus, based on its history to date, and if such a pattern holds for Portage Glacier, the glacier may now be in its stable retracted position and could eventually begin a slow advance.