Scientists have discovered a hidden world beneath Antarctica’s ice, where rivers flow uphill and could destabilize large coastal glaciers that control the rate of sea level rise. The findings, published in Nature Communications, reveal a landscape of steep mountains and valleys, traversed by meandering rivers fed by geothermal heat seeping from deep inside the earth.
The 20-year mapping project used ice-penetrating radar and precise measurements of gravity and magnetic fields to peer under the ice and found mile-high mountain ranges, broad valleys, and deep canyons. Radar also revealed several hundred subglacial lakes beneath the ice sheet, which are fed by water that melts off the base of the ice.
The hidden rivers obey not only gravity but also the crushing pressure of the ice overhead, allowing them to flow uphill in some cases. This phenomenon could lead to significant changes in the behavior of large coastal glaciers, including the Thwaites and Pine Island glaciers, which are spilling ice into the ocean more quickly than ever.
According to researchers, these changing rivers could cause a 20-50% increase in melting and thinning across a broad swath of the ice shelf. This increased melt could lead to the shelf breaking apart and potentially losing significant amounts of ice sooner than expected.
The scientists’ findings suggest that our current computer models for projecting future ice loss and sea level rise are too conservative, as they do not take into account the effects of subglacial rivers on melting rates. The study’s authors hope that improved maps and estimates of geothermal heat will lead to a better understanding of these hidden rivers and their impact on global climate.
Source: https://www.nationalgeographic.com/environment/article/rivers-glaciers-antarctic-ice-melt-sea-level-rise