Rock flour, a promising nutrient from melting Greenland ice

One day, perhaps, Greenland will be known the world over for its mud. A mud of such exceptional quality that it could, according to research by Danish geologist Minik Rosing, make the arid lands of the south fertile and reduce hunger in the world. “In Greenland, where we have the last piece of ice cap in the northern hemisphere, which is melting, billions of tons of very fine rock powder containing all the mineral nutrients absent in the tropics have been released”explained in a TEDx conference, in 2016, this professor at the Natural History Museum of Denmark, in Copenhagen.

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According to several experiments conducted in Brazil and Ghana, their use has increased maize production by 30%. Better known as glacial rock flour, the sediments are obtained from the ice which, as it melts, grinds the rocks into a fine powder which accumulates at the exit of the fjords. Greenland produces 1 billion tons per year, a figure which could however increase in the coming years, with the warming of temperatures, three times faster in the Arctic than elsewhere on the planet.

Just three days of unusual heat (10°C above the seasonal average) between 15 and 17 July were enough for the Greenland ice sheets to release, as they melted, 6 billion tonnes of water, i.e. equivalent of 7.2 million Olympic swimming pools, according to calculations by the US National Snow and Ice Data Center. Water very rich in silt. A study, published in 2017 in the journal Nature Geoscience by several scientists from the University of Colorado, showed that 8% of the suspended sediments in the water of the oceans came from the ice cap, while the latter released only 1.1% of the total volume of fresh water on the planet.

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It’s a great resourceexplained, in September 2021, the Greenlandic Minister of Mineral Resources, Naaja Nathanielsen. To exploit it, we don’t need to blow up the top of a mountain or build a processing plant. » Another interesting property of these sediments: they absorb CO2 in contact with the air. Thanks to its tiny particles, silt dissolves in rainwater, releases its nutrients and undergoes a chemical reaction that traps carbon dioxide from the atmosphere. This could even allow farmers to sell carbon credits by consuming glacial rock flour, and above all offset the carbon dioxide emissions from transporting them by boat.

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