High levels of CO2 make ice caps more likely to crack
Carbon dioxide weakens 'fracture toughness' of glacial ice, new MIT study finds
Excessive levels of carbon dioxide in the Earth's atmosphere is having a more profound effect on glaciers and ice caps than was previously thought, according to new research.
In an article published Thursday in the Journal of Physics D: Applied Physics, researchers from the Massachusetts Institute of Technology found the material strength and fracture toughness of ice decrease significantly under increasing concentrations of CO2 molecules.
That makes ice caps and glaciers more vulnerable to cracking and splitting into pieces, which in turn can contribute to global warming, the researchers concluded. This effect was seen last October when a huge crack in the Pine Island Glacier in Antarctica spawned a glacier the size of Berlin.
Ice caps and glaciers cover seven per cent of the Earth — a larger area than Europe and North America combined — and are responsible for reflecting 80 per cent of the sun's light rays that enter our atmosphere, thus helping stabilize the planet's temperature, the lead author of the study, Markus Buehler said.
They are also a natural "carbon sink", capturing a large amount of CO2.
"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.
"The consequences of these changes remain to be explored by the experts, but they might contribute to changes of the global climate," said Professor Buehler.
Buehler and his student and co-author, Zhao Qin, used a series of atomistic-level computer simulations to analyse the dynamics of molecules and investigate the role of CO2 molecules in ice fracturing. They found that CO2 exposure causes ice to break more easily.
Notably, they found that decreased ice strength is not caused merely by material defects induced by CO2 bubbles, but by the weakening of the hydrogen bonds in the ice itself, as the additional CO2 competes with the water molecules that are connected in the ice crystal.