When the Ice Is Gone

When the Ice Is Gone: What a Greenland Ice Core Reveals about Earth’s Tumultuous History and Perilous Future. Paul Bierman. New York: W.W. Norton & Company, 2024. 291 pp., references & index. $27.99 hardcover.

One of the consequences of our current climate crisis—of the inexorable global warming we are witnessing due to humanity’s pumping greenhouse gases into Earth’s atmosphere—is the melting of our planet’s ice sheets, including those on Greenland, Antarctica, and glaciers in mountains throughout the world.  We know this will lead to changes in weather patterns and to rising levels throughout the globe, but beyond that, most of us have little understanding of the long history of global ice and the complexity with which ice behaves.  Paul Bierman, an environmental scientist at the University of Vermont who studies ice, has written a marvelous book on the subject that vividly presents more than most of us thought there was to know about ice and our planet’s ice sheets.

The Saqqaq people first settled the west coast of Greenland about 4,500 years ago, followed by the Dorset people two thousand years later.  Today’s Inuit, called Thule Inuit, arrived about 1,500 years ago.  All these peoples learned to live in an environment that was very cold and snow-covered much of the year.  They moved about on dogsleds and small boats made of animal hide, subsisted largely on marine mammals, and made tools forged from iron they recovered from a giant meteorite, Saviksue, that landed on Greenland unknown ages ago.  Five hundred years later, during a brief period of global warming, Norse seafarers from Scandinavia established two settlements on Greenland.  Earth’s climate had warmed enough that Erik the Red and a few thousand Scandinavians were able to establishment permanent habitations based on pasturing livestock, farming a few crops, and hunting, especially walrus to use their tusks for trade.  After a few centuries, Earth’s climate cooled again, and by 1450, the Norse could no longer sustain their European modes of living on Greenland.  For the next few hundred years, Greenland had few European visitors.  That began to change in the early twentieth century, when a German scientist, Alfred Wegener, started taking expeditions to Greenland to study ice and atmospheric currents.  Wegener is best known as the first to hypothesize that Earth’s continents drift, i.e., the theory of plate tectonics.

Wegener and his teams of scientists were the first to try scientifically to understand the nature of large masses of ice, such as the Greenland ice sheet.  The greatest strides in scientific and engineering understanding of ice, however, began during the World War II, when the United States Army decided to establish an airfield on Greenland as one of several stop-overs for flying military aircraft under the Lend-Lease Program to America’s allies, Britain and the Soviet Union.  The Army quickly found that building an air strip on ice, and accompanying it with the necessary personnel and infrastructure, was more difficult than anyone used to building on land could have imagined.   Lessons learned during the war provided a basis for an even more ambitious construction project on Greenland launched in the early years of the Cold War.  American policy makers decided a permanent military presence was needed on Greenland to protect the Arctic region from perceived Soviet aggression and also to detect Soviet missiles, armed with nuclear warheads, that might be launched from bases in Russia, across the Arctic, to cities in the U.S.  Part of the project was establishing the U.S. Air Force’s Thule Air Base in northwestern Greenland

Bierman’s book establishes this history as context, along with the fact that the military forcibly removed native Greenlanders from areas where military installations would be built, but the book does not dwell there.  His main focus is to show the wide array of new facts the military, under the auspices of the Snow, Ice, and Permafrost Research Establishment (SIPRE), learned about ice, in both the scientific and engineering realms, to be able to build military installations on ice in the Arctic.  Without that science and engineering, it would have been impossible to undertake the drilling of ice cores from the top of Greenland’s ice sheet to its base, where the ice sits on Earth’s mineral crust.  And from those ice cores, scientists have learned much that we hadn’t known about how Earth’s climate has changed over the ages.

Trying to build housing and workspaces on Greenland’s permanent ice is difficult because each year more snow falls in winter than melts in summer, meaning that any structure built atop the ice will be buried in snow in a few years.  Perhaps a better place to build is beneath the ice, which would have the added benefit of protection from the weather.  That’s not as easy as it may sound because ice does not behave like land.  Ice is a solid, which we can see if we hit it with a hammer and watch it shatter.  But ice is also a fluid substance that flows and deforms (changes shape) very slowly under pressure.  For the U.S. military, trying to build permanent infrastructure on Greenland’s ice sheet, that meant a tunnel in the ice meant to accommodate housing or labs would change shape within a few years.  Another problem was that the operation required huge volumes of diesel fuel to generate electricity, heat habitable spaces, and melt water for human consumption and other uses.  So much diesel was required in the 1950s that the Army estimated that liquid fuel comprised seventy percent of the cargo shipped to supply the operations.  Moreover, burning diesel to melt ice made the water taste like fuel, and the workers hated it.  The military’s solution was to order a small, portable nuclear reactor to power the installation at Camp Century, the military’s main base of operations 138 miles from the west coast in far northern Greenland.  The camp got its name because it was intended to be located 100 miles from the coast, but the Army Corp of Engineers had to keep moving inland to find ice suitable for construction.

Bierman spends chapters detailing the military’s travails trying to establish a base of operations, and the important lessons scientists and engineers learned about the nature of ice during the effort.  In the late 1950s, SIPRE applied to the U.S. National Science Foundation (NSF) for a research grant.  Having entered the field of Arctic research, the NSF continued funding projects in Greenland and especially at Camp Century, leading to the effort to drill ice core a mile in depth through the ice sheet to the solid ground.  The first hole, drilled at Camp Totu near Thule Air Base in 1959, was able only to reach 89 inches in depth.  In 1960, scientists tried another hole at Totu (which had chapel carved within the ice, and an altar built of ice), reaching a depth of forty feet.  Having improved their technique and equipment, the drilling team moved to Camp Century in 1961 and succeeded in drilling a hole about 600 feet, but the drill got stuck.  The next year, they reached 780 feet before another technical problem ended the drilling.  There was no drilling in 1963, because the nuclear reactor had to be replaced.  The hole in 1964 reached 1,755 feet but again ended in failure.  Finally, in 1965, the drillers were able to mount a continuous campaign of drilling, now armed with drilling fluid comprised of diesel fuel and trichlorethylene (TCE), a nasty solvent and anesthetic that has been banned for human use since 1977 and banned in Minnesota for all industrial uses since 2023.  Making rapid progress, the drillers reached the bottom of clear ice, at a depth of 4,454 feet, on July 2, 1966, and entered a zone of silty ice.  After another 45 feet of ice core, they reached the bottom and began recovering 11 feet of core containing sand, rocks, and ice.

Over the ensuing decades, scientists in the U.S. and Denmark (Greenland is a Danish possession, which gained levels of semi-autonomy in 1979 and 2009) have analyzed ice core, using an amazing array of analytical methods to determine levels of carbon dioxide in the atmosphere each year when a layer of snow fell, and also the relative temperature of the weather when the snow was made, making the ice core an amazing library of global history.  Although a scientist, Bierman is able to explain the methods used in analyzing ice core, and the findings based on those analyses, with a clarity easy for a lay person to follow.  But Bierman wrote the book because of a rare opportunity that opened to him in the late 2010s.  Scientists had been analyzing Greenland’s ice core for decades, but amazingly no one had gotten around to analyzing the frozen core taken from beneath the ice.  In fact, the frozen sediments had attracted so little attention that their whereabouts was unknown.  In 2017, Bierman was informed by a Danish scientist that they had the sediment cores in frozen storage in Denmark.  They and other colleagues organized a gathering of scientists from numerous sub-specializations who could analyze various facets of the sediment core, secured funding to conduct the research, and began writing papers about their findings.  The team’s 2021 report is titled, “A Multimillion-Year-Old Record of Greenland Vegetation and Glacial History Preserved in Sediment beneath 1.4 km of Ice at Camp Century.”

Bierman was part of the small group that first discovered there were bits of plant matter in that sediment core, and those plants still live on Earth today.  With today’s amazing analytical methods, the scientists were able to identify the plants that once grew on Greenland’s land surface when there was no ice.  Parallel analyses show that the concentration of carbon dioxide in the atmosphere when Greenland had no ice was only about 280 parts per million (ppm).  Thanks to human-produced greenhouse gases, we now have more than 420 ppm of carbon dioxide in the atmosphere, global temperatures are rising, and ice sheets are rapidly melting.

When the Ice Was Gone ends with Bierman’s descriptions of some of the things that will happen to coastal cities around the globe as sea levels rise.  His final argument is that we not only have to stop discharging greenhouse gases into the atmosphere; we must find ways to take carbon out of the atmosphere if we want to prevent Greenland’s ice sheet from disappearing.  We now know the ice disappeared once before when levels of carbon dioxide in the atmosphere were much lower than they are now.

This book reads like an adventure story, with intrepid military officials trying to conquer the ice and with scientists making important new discoveries, but its message about disappearing ice is also an important one as collectively we try to chart a sustainable path to the future.

Fredric L. Quivik