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[Music, low plane engine sound] Narrator: Below thousands of meters of ice

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ice in Antarctica, lie hundreds of meltwater lakes

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where the Antarctic Ice Sheet meets the continent’s bedrock.

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Until pretty recently we thought that these lakes sat quietly,

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isolated in pockets under the ice.

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But in 2007 laser measurements of the ice surface

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from NASA’s ICESat satellite were used to infer what was happening far below.

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And a much more interesting picture was revealed. 


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By watching local areas of the surface

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of the massive ice sheet rise and fall

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due to fluctuations in the lake water levels below,

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we learned that vast hydrologic systems like rivers connect many of these lakes,

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and that some actively fill and drain all the time.

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Thanks to the more advanced laser technology

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on NASA’s ICESat-2 satellite, in a region very near

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near a pair of larger lakes measured in 2007,

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two more of these lakes have just been found.

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A new study shows they are currently experiencing a draining period.

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The finding also gives us the most detailed picture yet

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of how the boundaries of lakes can change over time.

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Areas seen here in blue

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show that the surface of the ice is getting lower,

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which indicates that the lakes below are draining.

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Understanding how much water is flowing under the ice sheet, and how quickly

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quickly it can drain to the sea, helps give us a better picture

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of not only how quickly the Antarctic Ice Sheet will change

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due to a warming climate, but also how Antarctic melt will affect

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both global ocean currents and sea level rise.

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[music fades]