February 4, 2019
Thwaites Glacier Startles Scientists
by Robert Hunziker
“It’s a disturbing discovery,” according to Pietro Milillo, a radar scientist at NASA’s Jet Propulsion Lab, who co-authored a recently published study: Heterogeneous Retreat and Ice Melt of Thwaites Glacier, West Antarctica, Science Advances, Vol. 5, No. 1, Jan. 30, 2019.
It’s only within the past 10 years that NASA’s IceBridge Mission has served as the largest airborne survey of Earth’s polar ice, providing unprecedented three-dimensional views of Antarctica’s ice sheets, ice shelves and sea ice. Scientists are now able to peer into glaciers with remarkable accuracy to see what’s happening.
Indeed, scientists are getting an eyeful, and they are discovering the true impact of global warming, which is much more powerful and happening considerably faster than they ever dreamed possible.
After all, the ocean has been absorbing most of the planet’s heat, and that heat finds its way underneath in the water, thus creating gigantic melt holes, like the recently discovered Thwaites Big Cavity. As such, considerable damage is/has been hidden from view.
The new NASA study, utilizing IceBridge, shows a surprising loss of 14B tons of ice in only three years from the Thwaites Glacier, where a humongous hole lurks beneath the glacier’s icy/snowy surface, a massive cavity nearly the size of NYC but hidden within the core of the ice sheet.
Fascinatingly, it’s calculated that Thwaites is responsible for anywhere from 5% to 10% of worldwide annual sea level rise (“SLR”). By the time the monster glacier disappears from the face of the planet, it alone will equal nearly two feet of SLR. But, how soon Thwaites fades away within Antarctica’s mid-summer 24-hour endless sunlight is a big mystery.
Thwaites Glacier is one of West Antarctica’s big kahunas. It’s 100 miles across and 4,000 feet deep. Surprisingly, and disturbingly, it’s melting earlier and much much faster than ever thought possible, which is downright spooky for a humongous icy glacier that has a permanent face in Antarctica ever since the dawn of humanity.
It should be noted that Thwaites, assuming it collapses and triggers a series of collapsing glaciers surrounding it, serves as a major-major backstop to a larger potential catastrophe on West Antarctica. Still, an event that catastrophic would likely happen well beyond current lifetimes. However, on a cautionary note, timelines for climate change have become moving targets, almost always way too timid.
Thwaites is one more crushing example of scientists exclaiming: “Uh-oh, this is happening much faster than we ever thought possible.” That’s become a common acknowledgment by scientists. Climate change is happening faster and faster, surprising scientists, as their “models” get blown away by new data.
It was only 5 years ago when scientists said the Western Antarctica ice sheet “collapse had started” but the same researchers said: “Even though sea level rise could not be stopped (10-13 feet) it is still several centuries off, and potentially up to 1,000 years away.” No sweat!
Now they are sweating.
Making matters dicey-er yet as for urban coastal planners, the United Nations’ IPCC most recent report did not factor in a melting of the Western Antarctica ice sheet into calculations of sea level rise this century.
Surprise, surprise, it’s happening so much faster.
According to the aforementioned study: “The Amundsen Sea Embayment (ASE), (Thwaites is one of several glaciers in the embayment) sector of West Antarctica is a dominant contributor to sea level rise at present and for decades to come,” Ibid.
Furthermore, it’s worth noting that, unfortunately: The fast-flowing main trunk of Thwaites accelerated 33% between 1973-1996, but lo and behold, the rate quadrupled in 2003-2010, flowing at a rate of 9.5 Gt/yr versus 2.2 Gt/yr previously. That’s 4xs faster, blowing away the old 1973-96 rate of 33%. Geologically speaking, Thwaites is a virtual supersonic melt speed demon.
Of course, once there’s a big new discovery (surprise-surprise) like Thwaites, the odds of similar glacier scenarios are quite high. After all, Antarctica is the largest desert in the world covered by a couple miles of ice equivalent to about 200 feet of sea level rise. There are plenty of potential additional scenarios.
With a sense of urgency, the U.S. and Great Britain have announced a $50M joint venture known as the International Thwaites Glacier Collaboration to probe the glacier in every conceivable manner to discover ahead of time how precarious it may be.
And, collaterally, whether science has been way too tardy in identifying the risks associated with global warming.
Robert Hunziker lives in Los Angeles and can be reached at rlhunziker@gmail.com.
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