The discovery put the scientific community on alert. A giant crack, covering two-thirds of the Manhattan area and has a height of almost 300 meters, is growing on the background of the Thwaites Glacier, which is the size of Florida and is located in West Antarctica.
Scientists knew there was space between ice and rock at the bottom of the glacier. They are cavities through which water can flow, which over time can lead to ice melting block From below.
But the size and rate of crack growth has baffled them. The magnitude could have allowed it to contain 14 billion tonnes of iceand almost everything has melted in the past three years, according to a NASA report released by the Reaction Propulsion Laboratory (JPL).
"We suspect the Thwaites were not very attached to the bedrock beneath it"said Eric Rignot of the University of California at Irvine and JPL in Pasadena. Rignot co-authored the new study, published on January 30, Advances in science. "Thanks to a new generation of satellites, we can finally see the details," he said.
"The size of a cavity under a glacier plays an important role in the melting," said lead study author Pietro Milillo, also of JPL. "The more heat and water penetrates the glacier, the more it melts faster".
The Thwaites glacier is responsible for approximately 4% of sea level rise in the world. It has enough ice to raise the level of the oceans to just over 65 centimeters. But there is something worse: as it contains the neighboring glaciers, if they collapsed, the sea level would rise another 2.4 meters.
Another study, published months ago Nature, revealed that the ice cap (the frozen mass that covers the continental surface) has lost 3 trillion tonnes since 1992. Millions of tons of ice are melted each year – which are incorporated into the oceans, now at an additional 7.6 millimeters – with the aggravating fact that the melting rate has tripled in the last five years.
From 1992 to 2011, Antarctica lost almost 84 billion tonnes of ice per year; but From 2012 to 2017, the number rose to 241,000 million tons per year. "We can see the melting, which is occurring in West Antarctica," said Andrew Shepherd, a professor at the University of Leeds and director of Wired. This site, he added, reveals the reason for the phenomenon: "We know the ocean in the West Antarctic is very hot".
"It's too much for the ice to resistand thus melts and causes sea level rise, "he continued. the ice cap is not impervious to the effects of climate change as we thought it would be. And this is an alert. "
According to this work, in case the thaw follow this step would have to add about 15 centimeters more to the estimated height of sea level rise. For example, that would be about 25 centimeters by 2070, with a disastrous impact on coastal cities and the displacement and feeding of people.