Alaska diary: Climate change and snowshoe hares

"Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global sea level."  -- Intergovernmental Panel on Climate Change, 2007 

That's what the Park Service pamphlet -- Climate Change in National Parks -- proclaims.  Ranger Andy hands out copies to his evening group of campers and walks us through what climate change means for Alaska and Denali National Park.

Among his most impressive "Powerpoint" graphics this evening is a color-coded map showing which regions of the earth have experienced the greatest increase in average annual temperatures, red being the most extreme increases.  Leading the world, by a large margin, is the Arctic zone, a red mass at the top of the graphic, a whopping 4 degrees hotter than it used to be.

The National Oceanic and Atmospheric Administration (NOAA) has studied what is called the "polar vortex" -- the wind patterns that used to circle the polar ice cap, trapping cold air at the North Pole.  Changes in those patterns have permitted warmer air to move across the Pole during the winter, which means that less ice forms and therefore when it melts in the summer, less ice is left to cover the polar sea.  The ice cap has shrunk by 30% in the last 5 years and may be reaching critical mass, where melting is accelerated.

All the numbers barely hint at the consequences for plants, animals, and humans.  Andy shows photos of tundra and towns in northern Alaska where the melting of permafrost results in "subsidence" -- a term describing how the ground is literally sinking under buildings, roads and bridges.  The ground under the tundra usually remains frozen even during the summer months.  But not with all the recent changes in weather patterns in the Arctic.

Industrial and auto emissions, deforestation, and other burning of fossil fuels (ironically supplied by the Alaskan pipeline in some cases) are widely confirmed as causing rising atmospheric temperatures -- even though they occur thousands of miles and continents away.   The resulting damage to Alaska's infrastructure and personal property poses enormous financial challenges to individuals and to local and state governments, not to mention the disruption in the lives of people affected by this damage.

Ranger Andy talks about the pika, a small alpine mammal that survives only in cold climates.  This little round-eared member of the rabbit family has been forced to seek higher and higher habitat due to rising temperatures in Alaska, Canada, and mountainous regions of the lower U.S.  In some cases, that habitat has simply run out.  The pika has nowhere higher to go when a mountain that used to remain sufficiently cool during summer months, is now too warm even at its summit for these tiny creatures to survive.

Similar catastrophe faces polar bears and walrus.  Because of melting Arctic seas, these animals must swim long distances rather than hopping from ice floe to ice floe in search of food.  In the case of the polar bear, scientists predict that they may be extinct by the end of this century if not before unless melting of the polar ice cap is reversed.  Likewise, because walrus cannot float on ice floes between feeding grounds, they are forced to overgraze clam beds in fewer available locales.  As a consequence, their numbers are also shrinking.  (I saw To the Arctic on the IMAX screen at the Natural History Smithsonian a few weeks ago.  The film depicts the bleak future polar bears and walrus face in open seas, although hope remains if we act now.  Highly recommended if available in your area.)

As for effects on flora, I already knew something of how warmer winters affect mountain environments.  In Colorado our winters in the high country include plenty of days when the thermometer doesn't rise above zero degrees Fahrenheit.  At elevations above 8000 feet, sub-zero winter days are common.  A typical Colorado winter thirty years ago would contain stretches when temperatures stayed well below zero for 5-10 days or longer.  Although we didn't realize it at the time, these cold weather days had important effects on insect life with direct consequences for Colorado's extensive lodgepole pine forests.

Hard winters normally kill pine beetle eggs and larvae in the bark of lodgepole and other pines and spruce.  A combination of milder temperatures and lower precipitation the past 10 years has resulted in an outbreak of beetles which have destroyed huge swaths of trees.  Whole hillsides of trees in the Grand Lake area near Rocky Mt. National Park have turned from lush forests into a wasteland of dry timber.  These blighted areas increase fire danger and the chance that when fires do start, they will spread faster and cause more damage.  This past summer's Colorado fires were fed by both drought conditions and by areas of dead trees damaged by beetle kill.

Andy concludes the talk with everyone sharing one thing he or she will do personally to halt climate change.

Perhaps because the previous evening's talk was on a somber topic, the following day Andy takes a lighter approach.  He focuses on park wildlife, passing around pictures of various animals that reside in the park -- bear, caribou, wolves, foxes, lynx, snowshoe hare.  He intentionally calls the hare a rabbit, which is the cue for his wife, Magali, to hop into the camp amphitheater costumed with bunny ears, nose, and tail and huge white hare-like feet (which are actually air-insulated winter boots).  She lectures Andy, and the rest of us, in her charming French accent about the fact that she is a "hare" and not a "rabbit."

 "And I change my coat from brown in summer to white in winter," says hare Magali.

"Why is that?" asks Andy.

"Don't you know anything, you silly Ranger?" says the hare.  "To camouflage myself so I will not be eaten by -- I hate to say his name -- the lynx."

And so it goes.  We laugh and learn as the hare hops about.  Magali has a future in comedy if the allure of the outdoors ever wears off, which I seriously doubt it will.  

As campers depart, we pose for a picture with Andy and Magali and friends from Taiwan we have met in the camp (more on them in a later post).  A hopping good time in Wonder Lake.