Antarctic meteorites being lost to climate change, study finds

New Delhi: About 5,000 meteorites are being lost in Antarctica because of ice melting caused by climate change, new research has found.

Scientists are calling for a major international effort to preserve the scientific value of meteorites as these space fragments provide insights into the origin of life on Earth, along with "secrets of the universe".

The scientists said the Earth is losing meteorites at five times the rate at which these are being recovered from Antarctica -- the most prolific place to find meteorites -- and urged for a need to "accelerate and intensify" recovery efforts.

Using satellite observations, AI and climate models, the research team also calculated that for every tenth of a degree rise in global temperatures, an average of roughly 9,000 meteorites disappear from the ice sheet surface.

They further projected that by 2050, about a quarter of the Antarctic meteorites -- estimated to be between 300,000-800,000 -- could be lost to glacial melt and about three-quarters could be lost under a high-warming scenario before the end of the century.

Rapidly cutting greenhouse gas emissions is the only way to preserve the remaining unrecovered meteorites, the researchers said.

"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 while working at the Department of Civil, Environmental and Geomatic Engineering at ETH Zurich, Switzerland.

Meteorites absorb more heat compared to the surrounding ice. As some of this heat transfers to the ice, some of it melts locally, causing the space fragments to sink underneath the ice sheet surface. Having sunk in, even at shallow depths, the meteorites cannot be detected anymore and are thus "lost for science", the researchers explained.

"Even when temperatures of the ice are well below zero, the dark meteorites warm so much in the sun that they can melt the ice directly under the meteorite. Through this process, the warm meteorite creates a local depression in the ice and over time fully disappears under the surface," said Veronica Tollenaar of the Université Libre de Bruxelles, Belgium, and co-lead of the study published in the Nature Climate Change journal.

"As atmospheric temperatures increase, the surface temperature of the ice increases, intensifying this process, since less heat from meteorites is required to locally melt the ice," said Tollenaar.

To date, about 60 per cent of all meteorites ever found on Earth have been collected from the surface of the Antarctic ice sheet, the researchers said.

They explained that the flow of the ice sheet concentrates meteorites in "meteorite stranding zones", where their dark crust allows easy detection.

Data-driven analysis for identifying unexplored meteorite stranding zones, along with mapping areas exposing blue ice where meteorites are often found, could improve the efficiency of meteorite recovery, the team said.

Inputs from PTI