Rising global temperatures could reveal an ice-free area in Antarctica comparable in size to Pennsylvania by 2300, potentially radically changing both the geopolitics and geography of the continent.
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A study published in Nature Climate Change is the first to factor in isostatic adjustment of glaciers — the uplift of the ground beneath heavy ice sheets as they retreat — into predictions of the emergence of ice-free regions in Antarctica. The findings suggest that climate change could reveal valuable mineral resources, potentially leading to a renegotiation of the international treaties that currently govern the continent.
As more and more ice-free areas appear in Antarctica, according to Erica Lucas, a geophysicist at the University of California, Santa Cruz and lead author of the study, countries may show increasing interest in the region's mineral potential. Beneath Antarctica's ice sheet lies a diverse landscape of mountains, canyons, valleys and even volcanoes. As the climate warms, the ice gradually retreats, revealing parts of this hidden terrain.
However, until now, predictions of the emergence of ice-free regions in Antarctica have only considered changes in the ice sheet boundary — that is, how the geographic extent of the ice sheet changes. Simulations of future accessible Antarctic terrain have not considered how the terrain will rise when exposed by ice, nor how different sea-level rise scenarios will affect the extent of ice-free regions.
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Erica Lucas's predictions incorporated these factors, including expected sea level changes, data on the thickness of Earth's lithosphere, and estimates of how the absence of the gravitational pull of the ice sheet affects land uplift.
The study estimates that by 2300, 120,610 square kilometers will be exposed under high-melt conditions, 36,381 square kilometers under moderate conditions and just 149 square kilometers under low-melt conditions. “We know that over the past two decades there has been a retreat of glaciers and their contact line with the seabed,” said Lucas, noting that the ranges in the predictions are not surprising.
In the region that Erica Lucas and her research team estimate will be ice-free by 2300, known or potential deposits of copper, gold, silver, iron, and platinum are found — minerals vital to industry but also highly valuable in their own right.
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Specifically, the study shows that the largest area of new ice-free land in Antarctica is expected to appear in areas claimed by Argentina, Chile and the United Kingdom, where there are various mineral deposits, such as copper, gold, silver and iron.
