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Microscopic life forms are causing ice sheets to melt faster

By Hazel Pfeifer, CNN

Published 9:12 PM ET, Mon December 14, 2020
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Greenland's ice sheet is the single biggest contributor to global sea level rise and recent studies show it's melting faster than expected. Here, on the ice sheet's southwestern side (pictured in summer 2017), water generated by melting ice carves rivers into the surface. Joseph Cook/@tothepoles
An iceberg "calved" off the Greenland ice sheet, floating along the coast of Upernavik, Greenland, in 2018. Ice melt has accelerated rapidly since the 1990s and Greenland lost more ice during 2019 than in any year on record. Joseph Cook/@tothepoles
The surface of Greenland's ice sheet is darkened by a type of algae that speeds up the ice melt. The algae produces a pigment that acts like a "natural sunscreen" and gives protection from the Arctic sunlight. The pigment causes the ice underneath to melt. A group of scientists from the UK's National Environmental Research Council project "Black and Bloom" set up camp on the ice sheet in 2016 to study the impact of these microbes on the ice. Joseph Cook/@tothepoles
Greenland's ice sheet is also under threat from other microscopic lifeforms that thrive on the surface of the ice. One type of bacteria causes sediment to form, creating what's known as cryoconite holes on the surface of the ice. The largest holes in this image are approximately 20 inches in diameter. Joseph Cook/@tothepoles
British glaciologist Joseph Cook was part of the "Black and Bloom" research team. He studies microbes and their role in accelerating ice melt. Using new technology, he models how they will impact sea level rise in years to come. Here, he is preparing some equipment for measuring the reflectivity ("albedo") of Greenland's ice sheet in summer 2016. Marc Latzl/Rolex
Cook's research on microscopic life forms that grow on glaciers and ice sheets has taken him from pole to pole, including an expedition to Livingston Island, Antarctica, in January 2020. He and his team were investigating microbial activity in the ice and in meltwater from several glaciers around the island as part of the UK National Environmental Research Council project "MicroMelt." Joseph Cook/@tothepoles
Blocks of ice calve into the ocean from a glacier on Livingston Island, Antarctica. Cook says this form of ice mass loss, in addition to surface melting, is accelerating in the world's frozen regions due to the warming climate. Joseph Cook/@tothepoles
The Antarctic peninsula is one of the fastest warming regions on the planet and its wildlife is also experiencing the impact of climate change. Warming has reduced the availability of krill -- tiny crustaceans that are the primary food source for penguins, and are also eaten by seals. Joseph Cook/@tothepoles
Penguins tending a nest on the beach on Livingston Island, Antarctica, in January 2020. Researchers recently discovered a dramatic decline in Antarctic penguin populations -- some colonies have decreased by more than 75% over 50 years. Joseph Cook/@tothepoles
A calm fjord near Longyearbyen, Svalbard, in Arctic Norway, belies the changes that have been wrought on the region. The Arctic today is much hotter, greener and less icy than it was 15 years ago, according to a recent report by the National Oceanic and Atmospheric Administration (NOAA). Joseph Cook/@tothepoles
Snow cover on Svalbard in March 2019, before the start of the summer melt. Climate change has reduced snow cover in the Arctic, exposing more ice to sunlight and creating the perfect conditions for microbes to thrive. Joseph Cook/@tothepoles
A meltwater channel cutting through the snow-dusted surface of Foxfonna Glacier, Svalbard, taken by Joseph Cook in summer 2019. "The discoloration of the ice and snow is partly (due to) dust blown on to the surface and partly algae using sunlight to grow," he says.  Joseph Cook/@tothepoles
From above, Cook's image of Svalbard's Foxfonna Glacier shows the surface ravaged by crevasses, patches of rotten snow, bare ice and patches of dust and algae. Joseph Cook/@tothepoles
The darkening ice on the surface of Foxfonna Glacier shows that ice sheets are surprisingly dynamic and complex environments. "There are so many questions to answer," says Cook. "It's kind of like a theme park for a scientist because there's just so much to do." Joseph Cook/@tothepoles