Rising sea levels could become overwhelming sooner than previously believed – according to the authors of the most comprehensive study yet of the accelerating ice melt in Greenland.
Run-off from this vast northern ice sheet – currently the biggest single source of meltwater adding to the volume of the world’s oceans – is 50% higher than pre-industrial levels and increasing exponentially as a result of manmade global warming says the paper – published in Nature on Wednesday.
Almost all of the increase has occurred in the past two decades – a jolt upwards after several centuries of relative stability.
This suggests the ice sheet becomes more sensitive as temperatures go up.
‘Greenland ice is melting more in recent decades than at any point in at least the last four centuries and probably more than at any time in the last seven to eight millennia’ said the lead author Luke Trusel of Rowan University.
‘We demonstrate that Greenland ice is more sensitive to warming today than in the past – it responds non-linearly due to positive feedbacks inherent to the system.
Warming means more today than it did even just a few decades ago’.
The researchers used ice core data from three locations to build the first multi-century record of temperature – surface melt and run-off in Greenland.
Going back 339 years they found the first sign of meltwater increase began along with the industrial revolution in the mid-1800s.
The trend remained within the natural variation until the 1990s – since when it has spiked far outside of the usual nine- to 13-year cycles.