Fast-rising bedrock makes for surprisingly uplifting Antarctic news
News from Antarctica usually paints a grim picture of rapid ice loss and record-setting icebergs breaking loose, which is all feeding into a vicious cycle that speeds up further melting. But now, a new study reports some more uplifting findings: the Earth itself is rising at one of the fastest rates ever seen, and it may help stabilize the ice sheet.
According to a recent long-term study, the West Antarctic Ice Sheet is one of the world's most vulnerable places to climate change, losing more than 175 billion tons of ice each year since 2012. Last July, an iceberg the size of Delaware snapped off and floated away, and it's feared that could destabilize the remaining ice shelf.
But another factor could help counteract that problem. According to a new study, the bedrock below Antarctica is rising much faster than expected, which could dramatically increase the stability of the ice sheet and slow further loss.
The team measured the uplift rate using six GPS stations dotted around the Amundsen Sea Embayment, and found that the rock was rising at up to 41 mm (1.6 in) every year. That's surprisingly fast, the researchers say, especially compared to the 20 to 30 mm (0.8 to 1.2 in) rise seen in other rapidly-rising places. The team estimated that this will pick up speed over the next century, accelerating to a rate 2.5 to 3.5 times faster. One area in particular is estimated to sit 8 m (26 ft) higher in 100 years than it does today.
"These results provide an important contribution to our understanding of the dynamics of the Earth's bedrock, along with the thinning of ice in Antarctica," says Valentina R. Barletta, lead author of the study. "The large amount of water stored in Antarctica has implications for the whole planet. The new findings raise the need to improve ice models to get a more precise picture of what will happen in the future."
So what's causing the rock to rise so fast? According to the scientists, the Earth's mantle below the region must be hotter and less viscous than previously thought. As the weight of the ice is removed, the rocky crust is bobbing back up as it "floats" on the fluid mantle.
This movement might help protect the ice sheet from further damage. Much of the ice loss is caused by relatively warm waters flowing underneath and eroding the ice from below, but the rising rock is pushing the sheet higher out of the water. Although previous models suggested this feedback loop could have a positive effect, it was thought that the process would take too long to really help.
"We previously thought uplift would occur over thousands of years at a very slow rate, not enough to have a stabilizing effect on the ice sheet," says Terry Wilson, lead author of the study. "Our results suggest the stabilizing effect may only take decades."
Of course, this rare piece of potential good news isn't a free pass to ignore climate change. While this may slow the retreat of the West Antarctic Ice Sheet, other parts of the continent may not be so lucky, and any positive effects could easily be canceled out by rampant global warming.
The research was published in the journal Science.
Source: Ohio State University