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Melting glaciers help bind carbon



In the Arctic, Chaos has fully expanded, a region that now warms twice as fast as the rest of the planet. This summer, it has been hot under unprecedented heat, and forest fires have consumed 2.4 million acres in Alaska alone, releasing enormous amounts of carbon dioxide. It's so hot up there that thunderstorms occur near the North Pole, more common in tropical climes. Researchers have found that water catchment areas fed by melting glaciers actually absorb a significant amount of carbon dioxide, unlike their typical carbon dioxide-emitting flux. On average, in the 2015 melting season, these glacier flows per square meter (to be exact, not total ) consumed twice as much CO 2 as the Amazon rainforest. Ironically, glaciers that melt under the weight of global warming can help bind carbon and make such watersheds a previously unrecognized CO 2 sink.

it is not. For one thing, the sequestering power of meltwater can not keep up with our runaway emissions, or even other climate change emissions from the Arctic, such as melting permafrost. And if we continue to melt glaciers, the meltwater will also go out. Nevertheless, the results are a key element in understanding the monumentally complex carbon cycle on this planet.

Glacier rivers are very different from rivers around the world. One striking difference is that they are mostly abiotic ̵

1; algae and fish usually do not colonize them because they are just too cold. Instead of being full of life, they are full of sediment.

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"As these glaciers retreat or progress, so do they, in fact, each year form many very fine sediments that are only wide open in the landscape," says Kyra A. St. Pierre, a biogeochemist at the University of British Columbia and lead author of a new paper describing the results. Glacier melt water absorbs this sediment and makes it rich in minerals. These meltwater flows then accumulate in mineral-rich glacial lakes.

Jessica Serbu

Carbon dioxide flows freely across the water surface – the water can both absorb and release the gas. In a typical river, organisms consume organic matter and release CO 2 or breathe like humans. In this way, the river becomes a net carbon producer, since it is saturated with so much CO 2 that the water simply can no longer dissolve CO 2 from the air. The same applies to ponds and lakes around the world – they are greenhouse gas emitters.

Glazialschmelzwasser, however, does not have this organic respiration, so it can dissolve more CO 2 the air. The sediments that absorb the meltwater, in turn, consume the CO dissolved in the water 2 . "The sediments mix with the water and carbon dioxide from the atmosphere, which changes the chemistry of the river as it moves downstream," says St. Pierre. When the sediment reacts with the CO 2 part of the material dissolves so that the river itself becomes a meandering carbon sink – to an impressive extent.

During the relatively low-melting season of 2016 The rivers in this Arctic watershed consumed half as much carbon per square meter per day as the Amazon rainforest. But the year before, when the ice melt was three times as high, the rivers consumed on average twice as much as the Amazon. At one point, they have captured 40 times as much CO 2 as the Amazon per square foot. But even this is not total . The Amazon Rainforest is 2 million square miles, a span far exceeding the size of this glacier watershed.

Nevertheless, a previously overlooked carbon sink is created. It is extremely difficult to say how much meltwater from carbon glaciers is being caught worldwide, even before climate change plunges Arctic systems into chaos. The beauty of this work, however, is that it makes complex phenomena a little more understandable. "The Arctic is changing much faster than our best models predicted," said Rose Cory, a biogeochemist at the University of Michigan, who was not involved in this work. "In order to model or predict what is happening, we need to have this process information."

Researchers need to understand how fast-melting glaciers affect freshwater systems. And how much CO 2 could intercept this meltwater, so that scientists can build more robust carbon budgets or estimate how much carbon we can pump into the atmosphere if we want to achieve the goals of the Paris Agreement. "I think this study is a really good example of the work that's needed," adds Cory. These rivers and lakes absorb CO 2 yes. "But at the same time, there are also other changes in the high and low arctic that will dominate the release of CO 2 from warming," says Cory. "For example, the thawing of permafrost will release carbon dioxide, and that can not be offset by what happens in these glacial lakes." An increasingly chaotic carbon cycle comes into focus.


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