Large interannual variability in supraglacial lakes around East Antarctica

Antarctic supraglacial lakes (SGLs) have been linked to ice shelf collapse and the subsequent acceleration of inland ice flow, but observations of SGLs remain relatively scarce and their interannual variability is largely unknown. This makes it difficult to assess whether some ice shelves are close to thresholds of stability under climate warming. Here, we present the first observations of SGLs across the entire East Antarctic Ice Sheet over multiple melt seasons (2014-2020). Interannual variability in SGL volume is >200% on some ice shelves, but patterns are highly asynchronous. More extensive, deeper SGLs correlate with higher summer (December-January-February) air temperatures, but comparisons with modelled melt and runoff are complex. However, we find that modelled January melt and the ratio of November firn air content to summer melt are important predictors of SGL volume on some potentially vulnerable ice shelves, suggesting large increases in SGLs should be expected under future atmospheric warming. Antarctic supraglacial lakes (SGLs) have been linked to ice-shelf collapse and the subsequent acceleration of inland ice flow, but observations of SGLs remain relatively scarce and their interannual variability is largely unknown. This new study shows that lake area and volume vary substantially from year-to-year around the East Antarctic Ice Sheet and between ice shelves.

Automated summary

Observations of Antarctic supraglacial lakes (SGLs) are relatively scarce and their interannual variability is largely unknown. This study provides the first observations of SGLs across the entire East Antarctic Ice Sheet over multiple melt seasons. The results show that SGL volume varies greatly from year to year on some ice shelves, with more extensive and deeper lakes associated with higher summer air temperatures. Model predictions suggest that January melt and the ratio of November firn air content to summer melt are important predictors of SGL volume on vulnerable ice shelves.