There are plenty of ominous indicators of the consequences of climate change, but few are more worrying to scientists than the ice sheets of Antarctica at our planet's southern pole.
These ice sheets have been melting for quite some time, and it doesn't take a degree in physics to understand the risk there. As the ice melts it flows into the ocean, causing sea levels to rise. And rising sea levels are obviously a huge problem.
Now, new NASA-funded research published in the journal PNAS reveals a concerning complication. Scientists from the Georgia Institute of Technology, NASA Jet Propulsion Laboratory and the University of Washington ran hundreds of simulations to predict how one large ice sheet, Thwaites Glacier, could degrade over the next 50 to 800 years.
The results showed the glacier was more in danger of becoming unstable that previously thought.
Small changes could lead to a watershed moment
"Unstable" here means something very specific. An "instability" in an ice sheet essentially makes it a frozen, ticking time bomb. The area of the glacier behind where it cantilevers over the water is eaten away, which can cause the glacier's ice to break off and flow faster out to sea and add to rising sea levels.
What's more ominous, the research finds, is that once this instability is triggered it's hard, if not impossible, to stop.
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"If you trigger this instability, you don't need to continue to force the ice sheet by cranking up temperatures. It will keep going by itself, and that's the worry," lead author Alexander Robel said in a release.
In other words, even if climate change was magically reversed, it wouldn't necessarily stop the dangerous and rapid rise in sea levels that could be triggered by unstable ice sheets.
The 'worst-case' scenario
Robel, an assistant professor at Georgia Tech's School of Earth and Atmospheric Sciences, says the "worst-case scenario" could be a rise of two or three feet from the Thwaites glacier alone.
While Robel suggests engineers and planners start building future critical infrastructure farther away from the sea-level line, you don't need to pack up your coastal homes like it's high tide yet. This potential acceleration of sea level rise could come into full effect 200 to 600 years from now.
This seems like a long time from now, because we will all be dead by then. But the Earth and its future generations hopefully won't be, and climate scientists want to keep it that way.