Ground Truth Trekking: Expeditions to explore environmental issues.
Climate Change on the Northern Pacific coast
North warming quickly
Warming in a Land of Glaciers
Northern regions of the planet are warming faster than the rest of the globe. And the icefields of coastal Alaska and British Columbia are melting more quickly than the rest of the world's glaciers, making an outsized contribution to sea level rise. Climate change is a world wide problem. But our expedition takes place in a region both disproportionately sensitive and disproportionately important to this global question.
35,000 square miles of icefields and glaciers
Our trip skirts the edges of a vast land of ice, spilling from mountain icefields down towards the sea. From Southeast Alaska through Prince William Sound, we will paddle past calving fronts of tidewater glaciers and walk around those that end on land. Glaciers cover 35,000 square miles (90,000 square km) of Alaska and neighboring B.C., making up 13% of the mountain glaciers of the world, and containing some of the largest areas of ice outside of Antarctica and Greenland.
Blockade Glacier
Antartica and Greenland hold the vast majority of the world's ice. But mountain glaciers are melting faster. From the 1950s through the 1990s, glaciers in this region lost about a foot and a half of ice per year. Since then, melting has only been accelerating, to a rate of almost 6 feet per year from the mid 90s to 2001. Multiplied by all these glaciers, that's a loss of 23 cubic miles of ice per year. In this 2002 study, scientists estimated that the sea level rise due to melting of Alaska and B.C. glaciers was greater than the rise due to melting of Greenland ice.
Glaciers are controlled by the balance between summer melting and winter snowfall. Global warming leads to increased summer melting and shrinkage of the glaciers. Glaciers with a large amount of low-elevation area are particularly vulnerable. However, the effect of warmer winters is more complicated, because it can change precipitation patterns. In a few cases (such as the Taku glacier in Southeast Alaska), glaciers with a lot of high elevation area are getting more snow in the winter, and actually advancing.
Packrafting by the McCarty glacier
Of all the glaciers in Alaska, tidewater glaciers are melting and retreating the fastest. In Glacier Bay they're retreating faster than anywhere in the world. See animated pictures here. For tidewater glaciers, ice dynamics accentuates the effect of temperature on glacial retreat. The end of a stable tidewater glacier usually sits on a shallow part of the sea floor (an underwater moraine). Once it retreats a little, the end is back in a deeper basin. Calving rates increase, and the glacier shrinks back rapidly. So climate change can start off a cycle of retreat, and determine whether the glaciers will advance again, but once the cycle is going it can't be stopped.
Bear "Glacier"
Off the map
To travel through a land of melting glaciers is to walk on unmapped terrain. The USGS did much of its surveying in the 1950s, when most glaciers were far bigger than they are today. New and nameless lakes have appeared at the toes of glaciers, where the map shows only ice. Smashed trees are uncovered at the glaciers' edge, where they've been buried since the last advance of the ice.
Caribou in forest fire smoke haze
In recent years, massive forest fires have been burning across interior Alaska during the hot dry summers. Most of our trip is in the coastal rainforest zone, which very rarely burns. But in the boreal forests on the other side of the coastal mountains, fires are frequent. In south central Alaska, the spruce bark beetle epidemic has left large areas of dead trees which are especially vulnerable. Wild fires change the balance between forests and grasslands - favoring the grasses. It's possible that with global warming, increased fire may turn interior Alaska into a vast steppe.
Permafrost cliff on an arctic river
Most of our journey takes place just beyond the edge of the permafrost zone. We'll be passing through areas of discontinuous permafrost between Valdez and Anchorage, and in the Lake Clark, and Pebble Valley areas of the Bristol Bay watershed.
Much of the north is built on frozen ground. And when the ground melts, roads buckle and buildings collapse. Industries relying on ice roads (such as the oil and gas industry on the North Slope), can operate those roads for fewer and fewer months per year. In Alaska, damage from warming that has already occurred is estimated to be about $35 million per year.
Migration of species in response to climate change
Climate shifts change the balance between different ecosytems. When temperatures rise, forests and shrubs can move into alpine and northern realms formerly occupied only by tundra. This is already happening in both Alaska, and the Pacific Northwest. Conversely, more frequent forest fires can allow grasslands to invade formerly forested lands. As temperatures change, many plants and animals will be forced to shift their ranges. In this region, migration is made more difficult by the steep mountains and rugged topography, but the relative lack of human development across much of the area allows more room for these shifts.
Seattle freeway
Sources of CO2 emissions in the region
This region is not only a victim, but also a perpetrator of global warming. In Washington and British Columbia, emissions come primarily from the transportation sector - cars, trucks, planes, and ships. Compared to the rest of the U.S. and Canada, energy generation is a less important source of greenhouse gases in the region. This is because most of the electricity comes from hydropower, rather than from coal or gas-fired plants. Hydropower doesn't emit CO2, but it has other environmental costs, particularly for salmon.
In Washington, about 50% of the greenhouse gas emissions come from transportation, while in B.C. it's about 40%. Industry makes up most of the rest of it, with resource extraction, such as fossil fuel exploration and mining making up a big chunk of that.
Cook Inlet oil rig
In Alaska, the story's a little different. Per capita, Alaskans produce about four times more greenhouse gases than the already staggering U.S. average. Most of this comes not from individual consumption, but from power generated and used by industry - with the oil and gas industry the largest source. An additional 7% is just from methane released by oil and gas production. Transportation comes in second, mostly due to aviation. Because of Alaska's remote location, plane trips both for people and freight are longer and more frequent. One jet trip Outside (per person, on a full flight)has the equivalent impact of 5,000 to 10,000 miles of driving in a single-passenger vehicle.
References and Links
- IPCC - Intergovernmental Panel on Climate Change
- RealClimate - Climate scientists discussion board
- Grist - how to talk to a climate skeptic
- Global Warming: Early Warning Signs - Map of the world with regional impacts
- Pew Center on Global Climate Change - analysis and policy
- Green Facts digest on Arctic Climate Change - summaries of scientific consensus
- Global Warming in Alaska - World Wide View of Global Warming
- Glacier Mass Balance - from Wikipedia
- Global Temperature Trends - from NASA's Goddard Institute of Space Sciences
- Alaska Conservation Solutions - global warming in Alaska
- Anchorage Daily News article on Alaska CO2 emissions - February 2007
- Rapid Wastage of Alaska Glaciers and Their Contribution to Rising Sea Level - from Science, subscription required
- Glacier changes in southeast Alaska and northwest British Columbia and contribution to sea level rise - from Journal of Geophysical Research, subscription required
- Ecological Responses to Recent Climate Change - from Nature, subscription required