The rate at which basal channels beneath the Antarctic shelf are melting has been found to exceed prior calculations.
Previously, researchers determined the basal channel melt rate by relying on radar altimetry, which resulted in an undervaluation of figures by 42–50%. Fresh data, integrating stereo satellite imagery with altimetry readings, reveals that the typical melt velocity is reaching eight meters annually. A significant number of these channels face the prospect of breaching the surface of the ice sheet within just a few decades.
The Climate Significance of Antarctic Ice
The ice shelves surrounding the continent are vital for maintaining Earth’s high albedo by reflecting solar radiation. As this ice melts, the planet’s reflectivity decreases, and sea levels rise. If the global average temperature increases by 4.5 degrees, the potential for sea-level rise could climb to 10 meters over the span of 250 years.
Research Methodology
A team spearheaded by Anne-Sophie Sgubin employed optical satellite stereoscopic images sourced from the REMA database alongside altimetry data from CryoSat-2. Their analysis focused on nine vulnerable ice shelves, covering an area nearing 20,000 square kilometers. This effort yielded the first high-resolution map of basal melting, providing detail down to 50 meters.
Updated Projections and Ramifications
The combined analytical approach demonstrated that the melt rate for channels within ice masses up to 200 meters thick is eight meters per year, contrasting sharply with the previously assumed four to five meters. Shelfal glaciers such as Pine Island and Dotson are now projected to break through to the surface in just 17–25 years, rather than the previously estimated century. This finding underscores the critical need to revise current melting models and sea-level forecasts.
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