Scientists have previously revealed that Greenland's frozen ground cover is melting at a rapid pace, which is significantly increasing sea level. It's a stark reality that the complete melt of Greenland's ice and snow will increase global sea level by more than seven meters.

Now, a new study has come up with findings showing that the major contributor to the sea level rise is Greenland's vast network of little-understood rivers and streams, as they are moving the melt-water seaward.

UCLA geography professor Laurence Smith, lead author of the study, said it's an illusion to believe that Greenland is a vast plane of ice and snow. In reality, it is covered by branching streams, rivulets and even large flowing blue rivers, making it a very wet icescape. These all are playing a big role in removing melt-water from the ice sheet surface.

To provide you better insight into the mechanism, branching streams, rivulets and even large flowing blue rivers first carry the melt-water over the ice and then into the ice through sinkholes called moulins. This allows the melt-water to escape into the downstream edge and make its way to the ocean from there.

Researchers had to put in use a range of high-tech instruments to obtain their measurements because water was moving at a very high pace, and drainage into moulins was very unpredictable. Findings of the study have been published in the Proceedings of the National Academy of Sciences.

Smith said the contribution to sea level rise by waterways is even greater than lakes and ice calving combined. "So what our work shows is a clear and definite connection between climatological melting on the top of the ice sheet and the downstream outflow of water to sea level rise and floods in the rivers moving over the Greenland coast", added Smith.