Rick Forster is interviewed by world media about his research group's discovery of a Greenland aquifer
"We thought we had an understanding of how things work in Greenland, but here is this entire storage system of water we didn't realize was there," said Richard Forster, lead study author. The study was published online Sunday, Dec. 22, in the journal Nature Geoscience. The researchers discovered a large reservoir of melt water that persists within the snow just below the surface of the Greenland ice sheet all year round. The scientists say the water is stored in the air space between particles of ice, similar to the way that fruit juice stays liquid in a slush drink. The aquifer, which covers an area the size of Ireland, could yield important clues to sea level rise.
This new research finds that a significant amount is stored in partially compacted snow called firn. In the spring of 2011, researchers drilled deep into this layer and to their surprise, found liquid water pouring out of the firn cores brought back to the surface even though air temperatures were -15 degrees C. As this was well before the onset of the summer melt, the team concluded the water had persisted in a liquid state through the Greenland winter.
They believe that it holds roughly 140 billion tonnes of water, which is the equivalent to 0.4mm of sea level rise per year - about half of what Greenland contributes to the sea every year. But crucially the scientists don't know the ultimate destination of the water in the reservoir.
"It depends on whether it is currently connected to a system that is draining into the ocean or if it is a bit isolated and completely acting as a storage source without a current connection," said Prof Forster. "We don't know the answer to this right now. It's massive, it's a new system we haven't seen before - we need to understand it more completely if we are to predict sea level rise."
The scientists say the water is prevented from freezing by the large amounts of snow that fall on the surface of the ice sheet late in the summer. This insulates the water from the air temperatures which are below freezing, allowing the water to persist as liquid all year long.
Other researchers believe this discovery may help explain disparities between projections of mass loss by climate models and observations from satellites. Until now, calculations of the ice sheet mass changes did not include a year-round storage mechanism for liquid water.
Forster says the reservoir’s exact role is unknown. “It might conserve meltwater flow and thus help slow down the effects of climate change. But it may also have the opposite effect, providing lubrication to moving glaciers and exacerbating ice velocity and calving increasing the mass of ice loss to the global ocean.” As for whether climate change caused the aquifer to form, Forster says that’s not clear, but simulations of the Greenland Ice Sheet going back to the early 1970s would suggest it has been around for some time.
A video report of the story can be found here:
Water from the Greenland perennial firn aquifer draining from a core extracted 12 m below the surface of the ice sheet. The core was drilled in April, months prior to seasonal melt,
with air temperatures -15 C confirming the water was retained at depth
A few of the other stories:
Read the BBC Story
VOA News - Massive Lake Found Under Greenland Ice
Scientific American - Giant Aquifer Discovered Beneath Greenland
The Weather Channel - 100 Billion Tons of Water Discovered Beneath Greenland Ice