Heat-Trapping Carbon Dioxide Also Makes Ice Caps And Glaciers More Brittle

Photo: Bob Berwyn

by Bob Berwyn, via Summit County Citizens Voice

Have you ever poured a can of warm coke into a glass full of ice cubes and listened to the cubes crack?

Something similar might be going on in the atmosphere, as MIT researchers have shown that direct exposure to carbon dioxide makes ice caps and glaciers more susceptible to cracking.

The study is the first to show this kind of a direct impact from increasing atmospheric CO2, which as a heat-trapping greenhouse gas is directly responsible for much of the increase in global temperatures during recent decades.

The MIT study used a series of atomistic-level computer simulations to investigate the role of CO2 molecules in ice fracturing, finding that CO2 exposure causes ice to break more easily by directly affecting the hydrogen bonds between water molecules in ice crystals — because the added CO2 competes with the water molecules in the crystals.

Ice strength is also decreased by material defects induced by CO2 bubbles, according to researchers Professor Markus Buehler and Zhao Qin.

“If ice caps and glaciers were to continue to crack and break into pieces, their surface area that is exposed to air would be significantly increased, which could lead to accelerated melting and much reduced coverage area on the Earth,” said Buehler. “The consequences of these changes remain to be explored by the experts, but they might contribute to changes of the global climate,” he added.

Ice caps and glaciers cover seven per cent of the Earth—more than Europe and North America combined—and are responsible for reflecting 80 percent of the Sun’s light rays that enter our atmosphere and maintain the Earth’s temperature. They are also a natural carbon sink, capturing a large amount of CO2.

The study showed that CO2 molecules first adhere to the crack boundary of ice by forming a bond with the hydrogen atoms and then migrate through the ice in a flipping motion along the crack boundary towards the crack tip, where they accumulate and attack the water molecules by trying to bond to them. This leaves broken bonds behind and increases the brittleness of the ice on a macroscopic scale.

The research was published Oct, 11 in the Institute of Physics Journal of Physics D: Applied Physics.

Bob Berwyn is editor of Summit County Citizens Voice. This piece was originally published at Summit Voice and was reprinted with permission.

3 Responses to Heat-Trapping Carbon Dioxide Also Makes Ice Caps And Glaciers More Brittle

  1. Joan Savage says:

    Interesting but not at all conclusive. SciAm got an interview with Jeremy Bassis that brought out some of my hesitations.
    “Bassis also pointed out that glaciologists already know the fracture toughness of glacial ice, which could have been plugged into the computer simulation. “I’m a little disappointed that they don’t look at observations of the fracture toughness of glacial ice,” Bassis told OurAmazingPlanet. “I think it’s interesting that they have this idea that you’re changing the fracture strength, but my gut feeling is that is not what’s actually going on.”

    The Qin and Buehler model indicated there should be change in ice fracturing at CO2:H2O ratio of 0.2% (think 2000 ppm if that were atmospheric).

    I would not want to discount the possibility of a CO2 effect on present day ice, but I’d want to know a lot more about the microclimate of the ice-water-atmosphere interface. CO2 bubbles trapped in ice could make tiny locales of high concentration, but again, what is the evidence?

  2. Paul Klinkman says:

    By definition, ice is supposed to move a glacial speeds. However, once an iceflow coming off of the Greenland ice cap migrated 5 miles in 90 minutes.

    The ocean rose 30 feet in a period of less than 50 years, says one study performed in Mexico.

    If we learn that carbon dioxide makes ice brittle, then we have another indicator that one or more of the world’s great ice sheets might possibly collapse over a time period of 50 years or less.

  3. Paul Magnus says:

    US presidential debate…. climate change, meh!