Anytime you return to a place you lived many years before, you will likely be surprised by changes. You probably would not expect, however, to find the very shape of the land changed. For Global Warming 101 Expedition Team member Theo Ikummaq, however, this is just what happened when he arrived in his former home of Qikiqtarjuaq.

Theo lived in Qikitarjuaq in the 1980s. At that time the Distant Early Warning (DEW Line) station was not visible from town, the rise of the land blocked it from view. The DEW Line station can now be seen from town. The only explanation the local people can find is that the permafrost must have collapsed and let the land settle.

Permafrost is ground that remains frozen even in the summer. All of Baffin Island is permafrost. In the summer only the top of the permafrost, the active layer, thaws.

As the climate warms, the permafrost thaws to greater and greater depths. Across the Arctic melting permafrost is changing the structure of the ground. This destabilizes roads, buildings, pipelines, airports and other facilities. Sink holes form, trees topple, ponds and wetlands disappear, riverbanks collapse, and coastlines erode.

The impacts of melting permafrost extend beyond the Arctic. The Arctic permafrost holds large amounts of carbon, the basic building block of life. This carbon accumulated over thousands of years as living things died but, due to cold temperatures, did not decompose. As the permafrost melts, microscopic organisms decompose the carbon, releasing methane and carbon dioxide, both heat-trapping (greenhouse) gasses.

As the permafrost melts and releases its carbon to the atmosphere, that carbon intensifies global warming, which causes more melting of permafrost—a positive (self-reinforcing) feedback loop. There is enough carbon trapped in the Arctic permafrost that, if it were all to be released, it would dwarf human-caused emissions.

Melting permafrost is one of several potential feedback loops through which Arctic warming could have worldwide impacts. To learn about the other feedback loops, check out the Global Warming 101 lesson plans.

Elizabeth Andre

(Source: ACIA, 2004)

After leaving the Inuit village of Pangnirtung, the Global Warming 101team mushed along the edge of the retreating Penny Ice Cap on their way through the Auyuittuq National Park. The Inuktitut name of the park translates as “the land that never melts.” The Expedition Team, however, saw only the truncated ends of the glaciers that once snaked down from the Penny Ice Cap and surrounding peaks. They crossed over naked rock and jumbled moraines left behind after the glaciers’ retreat.

Rebecca Anderson, a researcher from the University of Colorado, told the Global Warming 101 team that much of the Baffin Island plateau was covered by permanent snow and ice during the Little Ice Age (about 1600-1900 AD), but that now there are only a few residual ice caps and these are disappearing rapidly. Anderson and Prof. Gifford Miller at the University of Colorado have been studying the retreat of some of these remnant ice caps on Baffin Island.

The tools Anderson and the other researchers use are aerial photography, sediment cores, stakes, dead moss emerging from beneath the ice caps as they retreat, and cosmogenic dating, which reveals the total time that rocks have been exposed at the surface. The University of Colorado research team flies in helicopters to the edge of the ice caps. They then camp near the edge, spending their days measuring the telltale signs of the ice caps’ retreat.

Anderson reports some of the Baffin ice caps have been around even longer than the Little Ice Age, but they are all now retreating rapidly. The Orion Ice Cap on the north end of Baffin Island has lost more than half of its area since 1958. If the small ice caps the researchers are studying continue to melt at their current rate, they will eventually disappear.

These and other Arctic ice caps hold large amounts of water. As they melt they will continue to contribute to world sea-level rise.

The Global Warming 101 Expedition Team will mush along the edge of the Barnes Ice Cap on their way from Clyde River to Iglulik. Daily updates of the team’s progress are available at www.globalwarming101.com .

Elizabeth

Local people tell us that when the snow comes right after the sea begins to freeze, it can keep the ice from thickening. It may seem strange to think of snow keeping something warm. Snow traps air, however, just like a fluffy comforter on a bed or the modern insulation in the outside walls of your house. This trapped air is a good insulator.

Even when the air temperatures get very cold, a thick layer of snow on the newly-formed sea ice can insulate the water from the cold air. The warmer ocean waters can then keep the ice from freezing to its usual depth.

Hunters and elders across Baffin Island have been telling us that with a warming climate, the snow often comes right after the ice begins to freeze. In addition to making the ice form not as thick, the layer of snow on the top can make it difficult for local travelers to notice if the ice is starting to melt from the bottom.

Many hunters and elders have told us that the ice used to melt from the top down. Now they say it melts from the bottom up. They say the snow blanket on top insulates the ice from the cold air and the warm ocean currents melt the ice from the bottom.

Because the ice still looks the same from the surface, it can confuse some travelers. There have been cases of people on snowmobiles falling through thin ice that looked fine from the top.

For much of the year the sea ice makes up a large part of the world of the local Inuit people. They travel over the ice to reach hunting grounds, neighboring communities and outpost camps. They stake their dogs on the sea ice and build fishing shacks.

Their safety and traditional way of life depends on ice and their ability to read it. Even a seemingly small change like the timing of the snowfall in relation to the ice freeze-up can have wide impacts.

Elizabeth