Greenland Ice Lakes Drain at Speed of Niagara Falls

Lakes on the surface of Greenland's ice sheet are draining through the kilometre-thick ice and roaring to the bedrock with a flow rate exceeding that of Niagara Falls.

The worry has been that with further global warming such meltwater would increase and have a catastrophic effect on the ice sheet, lubricating its base and making it slide quickly into the ocean. But a new study suggests that the meltwater's effect is not as strong as feared.

In the summer months, the surface of Greenland's ice sheet melts and the water pools on top, forming many lakes that are kilometres across. Researchers knew these lakes could drain quickly, but it wasn't clear exactly how they drained nor how fast.