We already know that as the planet warms, vast landscapes of ice are melting into water, which—presumably—follows a path determined by gravity and eventually joins the waters of the ocean. In Greenland alone, about 260 billion tons of ice are turning into water every year. And until recently, the process of melt and flow was assumed to be simple; melting ice would eventually merge into rivers that led to the coast, and the degree of melt would correlate in a clear and measurable way with rising sea levels.
But a team of researchers deployed to Greenland to measure and monitor the flow of the ice melt have stumbled on an unexpected twist in the simple story that begins with ice and ends with rising seas. Using acoustic measurements and mapping techniques facilitated by drones, the team has discovered a disparity between the disappearing ice and the volume of runoff, a disparity of between 20 and 60 percent. The ice is melting, but the total volume of resulting water isn’t completing the entire journey to the sea.
So…where is it going?
If researchers determine that a large proportion of meltwater disappears into pockets and crevices inside the ice sheet, this will dramatically alter existing models used to calculate the rate and extent of rising sea levels around the globe. The models will need to be adjusted to better reflect complex and unpredictable realities.
Some of these realities: the possibility that water may be flowing into areas below the surface that are protected from the direct rays of the warming sun. Also possible: the water may be flowing into “rotten” areas of ice with a porous consistency that collects fluid like a sponge. Also, changes in the color of the ice—potentially caused by microorganism populations—may alter the predicted speed of the melting process.
Nobody ever promised that measuring the impact of a warming planet would be simple. The researchers in Greenland are confronting this challenge in real time, and what they’re finding will contain important lessons for all of us.