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Figure 4. Earth’s “Third Pole” (TP, also known as the Tibetan Plateau). Melted snow and ice from the destroying environmental archives, much
TP generates major river systems including the Indus, Ganges, Salween, Mekong, Yangtze, and to the disadvantage of our scientific under-
Huang He. Red dots—population centers with > 1,000,000 people that are served by these major standing of natural history.
river systems; white dots—areas of glacier loss as measured on 7,090 glaciers across the TP from
the 1970s to 2000s (modified from Yao et al., 2012); blue triangles—average discharge of rivers. The In some places, the legacy of ice loss
base map and population centers are modified from Google Earth and the river drainages are mod- may be one of barren landscapes, as ter-
ified from International Rivers database. rain that witnessed the passing of thou-
sands of years during burial by advancing
change, water resources, and water reveal the natural and anthropogenic his- glaciers is now being rapidly exposed by
security (http://www.nap.edu/catalog tory contained within the ice, which in the substantially accelerating rates of retreat.
.php?record_id=13449). Greenland ice cap extends back over It is likely that these recently deglaciated
100,000 years. The EIS film Chasing Ice landscapes will not be re-occupied by ice
Loss of Natural Environmental and the multimedia production Earth: The during foreseeable human timeframes.
Archives Operators’ Manual (Alley, 2011) vividly In other places, forests or other vegetation
display the preservation of paleo-atmo- may rapidly colonize such landscapes.
Glaciers serve as both recorders and spheres within a glacier, as well as the loss Photographic records, such as those
indicators of climate change, as the ice of that archive that occurs during melting. included here, provide an outstanding ave-
contains archives of environmental condi- nue for education, because they display a
tions that prevailed throughout their exis- SUMMARY, LEGACY, AND record of ice that may never be seen again.
tence. Ice-core paleoclimatology plays an CHALLENGE
important role here, because the chemical This project has focused upon convey-
and physical properties preserved within Both satellite measurements of ice mass ing captivating imagery of ice loss to the
the glacial ice provide an essential long- and ground-based observations indicate public, through which we highlight the
term context for twentieth- and twenty- that Earth is losing ice; related studies forcing that the human combustion of fos-
first–century changes. The history of links show that warming temperatures are trig- sil fuels is exerting upon terrestrial sys-
between climate change and humans, and gering this dramatic response in the tems. Society is committed to additional
indeed the rise and fall of entire civiliza- world’s ice cover. The characterization of warming, perhaps moving well past the
tions, is well documented in low latitude rapid retreat of glaciers across Earth is well 1.5–2 °C target from the recent Paris
ice cores (e.g., Thompson and Davis, 2014). documented. Melting ice is contributing to Agreement, unless strong actions are
Snowfall that accumulates to metamor- sea-level rise, with concomitant disruption taken, perhaps growing from that accord.
phose into ice incorporates dust, volcanic of shoreline communities. It is apparent The rate at which glaciers are retreating
ash, smoke, and other atmospheric con- that feedback mechanisms, such as loss of provides one of the clearest indications that
stituents, as well as isotopic variations. buttressing near calving faces, can rapidly time is of the essence if human impacts are
Changes in the concentration of these con- accelerate this rise in human timeframes. to be limited. As geoscience educators, we
stituents can reveal changes in the distribu- Since glaciers are reservoirs for frozen attempt to present the best scholarship as
tion of land mass, ocean currents, deserts, water, the retreat of ice has other powerful accurately and eloquently as we can to
wetlands, and human activity. As the snow implications. As glaciers are lost, rivers address the core challenge of conveying
accumulates into annual layers that add receiving meltwater will increasingly be the magnitude of anthropogenic impacts,
mass to a glacier, a record of all these envi- susceptible to low flows during dry sea- while also encouraging optimistic determi-
ronmental conditions is preserved. Alley sons and drought, stressing societies that nation on the part of students, coupled to
(2000) discussed the array of analyses that rely upon those resources. Ice loss is also an increasingly informed citizenry. We
assert that understanding human perturba-
tion of nature, then choosing to engage in
thoughtful science-based decision making,
is a wise choice. Let us endeavor to tell the
story better. Savor the cryosphere.

ACKNOWLEDGMENTS

We thank our families for their enduring sup-
port of our curiosities, particularly when the pur-
suit of science results in extended absences with
concomitant risks to life and limb. Richard Alley
acknowledges the support of grants ANT 1043528
and AGS 1338832. Lonnie Thompson acknowl-
edge funding provided by the NSF Paleoclimate
Program Award ATM-0318430 and ATM-0823586.
James Balog acknowledges his extensive network
of private donors, Nikon USA, and, in the early
phases of EIS, the National Geographic Society.
Estimates of glacial retreats were provided by
Shad O’Neal, USGS, for the cover couplet; Eran
Hood, UASE, Fig. 2A; Einar Gunnlaugsson,
Iceland GS, Fig. 2B; Glaciology Group, ETHZ,

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