Antarctic ice melting rate has trebled in 21 years
The Antarctic ice shelf is under increasing threat from warming ocean currents and the rate of melting of glaciers has trebled in the last two decades, according to new research
The Antarctic ice shelf is under increasing threat from warming ocean currents and the rate of melting of glaciers has trebled in the last two decades, according to new research.
The ocean waters of the deep circumpolar current that swirl around the continent have been getting warmer and nearer the ocean surface over the last 40 years, and they could be accelerating glacier flow by melting the ice from underneath.
And a separate new study reports that the melting of the West Antarctic glaciers has accelerated threefold in the last 21 years.
Researchers from Germany, Japan, the UK, and the U.S. report in the Science journal that they base their research on long-term studies of seawater temperature and salinity sampled from the Antarctic continental shelf.
This continuing advance of warmer waters has accelerated the melting of glaciers in West Antarctica, and there is no indication that the trend is likely to reverse.
Karen Heywood, professor of environmental sciences at the University of East Anglia, UK, said: “The Antarctic ice sheet is a giant water reservoir. The ice cap on the southern continent is on average 2,100 metres thick and contains 70 per cent of the world’s fresh water. If this ice mass were to melt completely, it could raise global sea level by 60 metres. That is not going to happen, but it gives you an idea of how much water is stored there.”
Temperatures in the warmest waters in the Bellinghausen Sea in West Antarctica have risen from 0.8°C in the 1970s to about 1.2°C in the last few years.
Sunke Schmidtko, an oceanographer at the Geomar Helmholtz Centre for Ocean Researchin Kiel, Germany, who led the study, said: “This might not sound much, but it is a large amount of extra heat available to melt the ice. These waters have warmed in West Antarctica over 50 years. And they are significantly shallower than 50 years ago.”
The rise of warm water, and melting of the West Antarctic ice shelf, could be linked to long-term changes in wind patterns in the southern ocean.