John Mercer: Antarctic Eccentric Now Seen as Prophetic
May 27, 2014
It’s said he liked to conduct research on the Antarctic glaciers while nude. I like hard core types.
John Mercer was a glaciologist at Ohio State University, considered eccentric by his colleagues not so much for his dress, as for his predictions of near term collapse of Antarctic ice shelves due to climate change. The warning, published in 1978, has now been borne out, with recent publication of evidence that major ice streams on the West Antarctic’s “soft underbelly” have reached “a point of no return“. This will be the topic of my new video to be uploaded next week, one of the more terrifying pieces I have had to make.
Elsewhere on this page, see video of Dr. Jason Box, formerly a professor in the same OSU program where Mercer worked, on further implications of the new research for Greenland. (Dr. Box is now at the Geologic Survey of Denmark and Greenland)
The new finding appears to be the fulfillment of a prediction made in 1978 by an eminent glaciologist, John H. Mercer of the Ohio State University. He outlined the vulnerable nature of the West Antarctic ice sheet and warnedthat the rapid human-driven release of greenhouse gases posed “a threat of disaster.” He was assailed at the time, but in recent years, scientists have been watching with growing concern as events have unfolded in much the way Dr. Mercer predicted. (He died in 1987.)
COLUMBUS — Thirty-six years after catching flak for one of the most bold and dire predictions about global warming, former Ohio State University glaciologist John H. Mercer is being hailed as a visionary.
Mr. Mercer was hardly the first to sound an alarm about greenhouse gases: Scientists were well on their way by the late 1950s toward connecting mankind’s burning of fossil fuels to Earth’s changing climate.
But Mr. Mercer made a groundbreaking contribution with a peer-reviewed research paper about West Antarctica’s instability he got published on Jan. 26, 1978, in the scientific journal Nature.
In it, he warned the world that West Antarctica’s massive ice sheet — one of Earth’s largest and most important — would eventually melt from beneath, become dislodged, and cause global sea levels to rise 5 meters, the equivalent of nearly 16.5 feet.
Two of OSU’s most famous scientists, Lonnie Thompson and his wife, Ellen Mosley Thompson, studied under Mr. Mercer while earning their master’s and doctoral degrees.
The two founded the center’s ice core paleoclimatology unit, and have pulled ice core samples from numerous glaciers.
The ice, they said, yields clues to the Earth’s environmental history. They said Mr. Mercer’s views were hard for some scientists to accept in the late 1970s.
The conventional wisdom was that Antarctica was anchored. But Mrs. Thompson, who has been there many times, said advancements in underwater photography have shown the continent’s huge west shelf is melting from beneath from warmer ocean water, as well as from warmer air above.
“He was labeled an alarmist,” her husband said. “He had difficulty getting funded [after his paper]. And yet the science he did will last a lot longer than the science by others who have been much better funded. There were even glaciologists here who argued [West Antarctica] was stable at the time.”
According to Mr. Denton, the journal Science didn’t want to publish Mr. Mercer’s Antarctica paper, saying it “read like a Grade B movie.”
And, according to Mr. Elliot, the journal Nature originally rejected it as “junk science.”
“I hope he’s looking down on this,” Mr. Denton said. “I thought he was right all along.”
The vulnerability of the West Antarctic Ice Sheet, or WAIS, has been appreciated for a long time; all the way back in 1968, an eccentric Ohio State glaciologist named John Mercer observed that the WAIS was peculiarly unstable, and that it may have melted away in the geologically recent past. But Mercer (who, interestingly enough for a glaciologist, liked to do field work in the nude) published his observations in an obscure journal, and, according to the historian of science Spencer Weart, “did not push his views on colleagues.”
In more recent years, even as forecasts of global sea-level rise have been notched up, most projections have not taken into account the possibility of a significant, near-term ice loss from the West Antarctic. The most recent analysis by the U.N.’s Intergovernmental Panel on Climate Change forecasts a global sea-level rise for this century of somewhere between one and three feet; the new findings, according to Rignot, will require these figures to be revised upward.
Dr. Mauri Pelto, from 2009, in RealClimate:
Mercer’s ideas led Terry Hughes (1981) (my doctoral advisor at U. of Maine) to propose that the WAIS had a “weak underbelly” in Pine Island Bay. This bay in the Amundsen Sea is where the Pine Island Glacier (PIG) and Thwaites Glacier reach the sea. These are the only two significant outlet glaciers draining the north side of the WAIS. Together they drain 20% of the WAIS. Hughes called this area the “weak underbelly” because these glaciers lack the really huge ice shelves Ross Ice Shelf and the Ronne-Filchner Ice Shelf in which most other large WAIS outlet glaciers terminate.
Both glaciers have a relatively rapid flow from the WAIS interior to the calving margin. Further the low surface slopes and smooth flow patterns of PIG suggested to Hughes that there was no indication of a landward rise in the elevation of the glacier bed; such a rise would help stabilize the glacier. Without a rise in the bed, glacier thinning and retreat could result in continual grounding line retreat. The grounding line is where the bottom of the glacier comes in contact with the ground below the ice sheet, in this case the sea bottom. The grounding line is an anchoring point for the outlet glaciers.
The length of the glacier that is grounded is both slowed and stabilized by resulting basal friction. Beyond the grounding line toward the margin, the floating ice shelf is susceptible to rapid calving retreat and as the grounding line retreats, so would the calving front. Note in the image below that the situation is even less stable than Hughes speculated. The current grounding line is at a higher elevation than the bed of the glacier for the next 200 km inland of this grounding line. The deeper the basin, the thicker the ice must be to maintain grounding. This makes it tough to slow grounding line retreat once it begins in a deepening basin.