Antarctic meteorites are disappearing due to climate change
Unknown to many, the Antarctic region is a treasure trove of meteorites. More than 60% of all ~80,000 meteorites ever found on Earth are collected at the surface of the ice sheet. But now the warming climate is impacting these rocks, according to a paper published in the journal Nature Climate Change earlier this week.
Using artificial intelligence (AI), satellite observations, and climate model projections, a team of researchers from Switzerland and Belgium have calculated that for every tenth of a degree of increase in global air temperature, an average of nearly 9,000 meteorites disappear from the surface of the ice sheet, a news release from ETH Zurich, a public research university in Zürich, Switzerland, said.
US space agency Nasa describes meteorites as solid pieces of debris from a comet, asteroid, or meteoroid, that originate in outer space. These survive the passage through the atmosphere to reach the surface of a planet – like Earth – or moon. For scientists, these rocks hold answers to plenty of mysteries about our solar system.
These rocks are now disappearing at an alarming rate due to climate change. According to the paper, by 2050, about a quarter of the estimated 300,000-800,000 meteorites in Antarctica will be lost due to glacial melt. By end of the century, researchers anticipate that number could rise approaching a loss of meteorites closer to three-quarters of the meteorites on the continent under a high-warming scenario, the ETH Zurich news release said.
The researchers revealed in the study that ongoing warming results in the loss of about 5,000 meteorites a year, outpacing the collection efforts of Antarctic meteorites by a factor five. “We need to accelerate and intensify efforts to recover Antarctic meteorites. The loss of Antarctic meteorites is much like the loss of data that scientists glean from ice cores collected from vanishing glaciers – once they disappear, so do some of the secrets of the universe,” said Harry Zekollari, who co-led the study along with Veronica Tollenaar, Université Libre de Bruxelles. Zekollari is Associate Professor of Glaciology at Vrije Universiteit Brussel and co-led the study while working under Professor Daniel Farinotti in the Laboratory of Hydraulics, Hydrology and Glaciology at the Department of Civil, Environmental and Geomatic Engineering at ETH Zurich.
The flow of the ice sheet concentrates meteorites in what researchers call “meteorite stranding zones”. In these zones, their dark crust allows them to be easily detected, the release explains. However, due to their dark colour, meteorites also heat up with respect to the surrounding ice. “As this heat transfers from the meteorites to the ice, it can warm up the ice, and eventually cause the ice to locally melt, leading to a sinking of meteorites underneath the surface of the ice sheet. Once the meteorites enter the ice sheet, even at shallow depths, they cannot be detected anymore, and they are thus lost for science,” the release said.
Tollenaar said: “Even when temperatures of the ice are well below zero, the dark meteorites warm-up so much in the sun that they can melt the ice directly beneath the meteorite. Through this process, the warm meteorite creates a local depression in the ice and over time fully disappears under the surface.”