Greenland is a big island -- about the size of Saudi Arabia -- covered by ice and snow. But climate experts agree that frozen ground cover is melting at an accelerating pace, raising the sea level.
Greenland Icemelt
![The rivers and streams that carry glacial meltwater across Greenland’s ice sheet are a beautiful shade of blue, but the water moves so fast and drains so unpredictably into moulins or sinkholes that researchers needed to use a range of high-tech instruments to get their measurements. (UCLA/Laurence C. Smith)](https://gdb.voanews.com/0bc00e8d-42e9-4b50-894b-aad48c353722_w1024_q10_s.jpg)
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The rivers and streams that carry glacial meltwater across Greenland’s ice sheet are a beautiful shade of blue, but the water moves so fast and drains so unpredictably into moulins or sinkholes that researchers needed to use a range of high-tech instruments to get their measurements. (UCLA/Laurence C. Smith)
![Meltwater drains from Greenland’s ice sheet at such a fast rate that researchers couldn’t risk entering the water to get readings so they used a remote-controlled drone boat. (UCLA/ Laurence C. Smith)](https://gdb.voanews.com/95b2dfad-9657-4f56-a9b5-bb6fe8c3fe12_w1024_q10_s.jpg)
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Meltwater drains from Greenland’s ice sheet at such a fast rate that researchers couldn’t risk entering the water to get readings so they used a remote-controlled drone boat. (UCLA/ Laurence C. Smith)
![Researchers measured how fast water was flowing through rivers using an Acoustic Doppler Current Profiler. (UCLA/Laurence C. Smith)](https://gdb.voanews.com/c1328a4f-4e10-4c31-b657-c41b25bfb60a_w1024_q10_s.jpg)
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Researchers measured how fast water was flowing through rivers using an Acoustic Doppler Current Profiler. (UCLA/Laurence C. Smith)
![To calculate river flow, researchers used autonomous GPS beacons, which drift down the river broadcasting its location and velocity to communications satellites. (UCLA/ Laurence C. Smith)](https://gdb.voanews.com/0815b0df-429e-4a84-9f82-82e0c19ed43d_w1024_q10_s.jpg)
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To calculate river flow, researchers used autonomous GPS beacons, which drift down the river broadcasting its location and velocity to communications satellites. (UCLA/ Laurence C. Smith)