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The key role of thermokarst ponds The helicopter is here, ready to take us back to the village. Night will be falling soon, and we sadly won’t have time to land by the thermokarst ponds. Already frozen over this time of the year, the ponds, which act just like bioreactors, are key to the release process of frozen carbon. When the permafrost thaws, pieces of soil break off and fall into the water, providing nutrients and carbon to the bacteria and plankton living in the pond. The latter break them down into CO2 in the water layers near the surface, and into methane (CH4) at the oxygen-deprived bottom of the pond. “Researchers have analyzed the methane released from these ponds in various places in the Arctic,” says Warwick Vincent, the scientific director of the Centre for Northern Studies, which runs the research stations at Bylot Island, Umiujaq, and Kuujjuarapik. “In some of them, the carbon dates back to more than 40,000 years! This means that it is the old carbon stored in the permafrost that is being released into the atmosphere. And it’s not good news for the planet.” SPECIAL REPORT In any case, modeling gas emissions will be no mean feat. “There are millions of similar ponds in the Arctic, representing a total area of more than 200,000 km2,” Vincent reckons. Surprisingly, these thaw ponds have not always played a negative role: 15,000 years ago, in the first few millennia that followed the end of the last glacial period, they probably helped warm our still icy atmosphere before gradually filling in. Back in Kuujjuarapik, where we’re due to spend the night at the Centre for Northern Studies after a freezing afternoon out in the snow, a yet more chilling piece of news awaits: a polar bear was spotted the night before in the middle of the village, and the children are not allowed out until further notice. “When I was a kid, back in the 1950s, these things never used to happen,” says Alec Tuckatuck, an Inuit hunter met at the Centre. This is yet another effect of climate change in the Arctic: as their natural habitat, the sea ice, shrinks and becomes weaker, polar bears have taken to moving along the shores and entering villages in search of food. The next day, Kuujjuarapik is again in the throes of a blizzard. It will be some time before we are able to leave for Montreal. Meanwhile, the polar bear has been shot by hunters. ii Thawing permafrost threatens infrastructures For a long time, permafrost was considered as a permanent feature. So much so that thirteen out of Nunavik’s fourteen airports were built on it. No one at the time could have imagined that this ground, then as hard as concrete, could ever subside due to thawing. With the help of researchers, the airport at Salluit, whose runway was heavily damaged, had to undergo significant consolidation work. “We recreated the permafrost and inserted monitoring sensors into the runway,” explains Michel Allard, a Quebec researcher at the Takuvik laboratory. The ongoing thawing is impacting building projects at a time when housing development is becoming crucial for Inuit communities. “With the population explosion, Nunavik and its 12,000 inhabitants are faced with a serious housing crisis,” Allard points out. Not to mention the impact on the Plan Nord, launched by the Quebec government with a view to fostering economic development in the region. New building techniques will have to be developed while undertaking detailed mapping of the area. “We need to characterize the state of the ground, square kilometer by square kilometer, in order to predict how it will behave as thawing takes place,” Allard reckons. A mammoth task lies ahead for the scientists. “It is the old carbon that is being released into the atmosphere. And it’s not good news for the planet.” Damaged by thawing permafrost, the access road to the airport in Akulivik (northern Nunavik), had to be repaired. Alec Tuckatuck, an Inuit hunter, has seen the climate change since the 1980s, with longer summers and shorter winters. © L. CAILLOCE © CEN/TAKUVIK 37 SPRING 2015 N° 37


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