SINGAPORE – A colossal chunk of ice breaks from a glacier as it plunges into the ocean, its thunderous splash punctuating the seemingly quiet and frigid landscape of the Arctic.
But at the same time, masses of glacial ice continuously pop, cackle and bubble underwater – almost like the sound of a frying egg – as they lose their weight in meltwater.
This usually occurs in the warm summer months from May to August, and can be difficult to measure since much of the melting occurs underwater, said Dr Mandar Chitre, head of the Acoustic Research Laboratory at the National University of Singapore’s (NUS) Tropical Marine Science Institute.
Warming seas, which trap more heat from greenhouse gases like carbon dioxide, have led to the world losing some 21 per cent of its glaciers over the last two decades.
A recent study has shown through analysis of two decades worth of satellite data that even if the world were to limit temperature rise to 1.5 deg C, it could still lose around half of its glaciers.
This could go up to 68 per cent if global warming continues at its current rate at a temperature increase of 2.7 deg C.
With more glaciers disappearing over the century, its implications on sea level rise could be all the more drastic for low-lying island states like Singapore.
But how quickly is the ice melting and how will this affect the extent of sea level rise?
To understand this, Dr Chitre embarked on a mission some five years ago – with researchers from the Institute of Geophysics in Poland and the Scripps Institution of Oceanography in the United States – to the Norwegian archipelago of Svalbard to eavesdrop on the secret language of oceans: the sound of melting glaciers.
“When glaciers were formed thousands of years ago, they had air bubbles trapped inside them. Because of the weight of the snow and ice above it, the air bubbles are under high pressure and stay trapped inside the ice,” he said.
“However, when the glaciers melt and the walls become thinner, the bubbles explode through the glacier wall, as it is no longer able to contain the pressure, thus making the popping noise.”
Dr Chitre and the team are analysing the sounds of these popping bubbles to see if they can provide clues to the speed of glacial melt.