The image pair above illustrates one portion of the ice cap margin
as it appeared last week (upper), and just prior to our last
visit, in 2018 (lower). The red dots are co-registered to provide
a perspective on examples of change over the three years. As in the past, ice
recession has not been uniform along the margin. Retreat is
especially dramatic at the formerly proglacial lake Morojanicocha.
Collaborator Gustavo Valdivia visited this area in September, was
able to walk entirely around the lake, remarking that it is
"incredible how fast the ice is retreating".
Also note the change in waterlevel at the lake at the top of both
images. The obvious drop may reflect seasonal lowering during the
June - September dry season, but may also be a response to
longer-term hydrological changes associated with ice retreat.
Other environmental changes at Quelccaya are less easy to
interpret from imagery at this resolution, such as the magnitude
of glacier thinning. Also, changes in the volume and routing of meltwater
runoff from the glacier over time are difficult to assess from
imagery, due to the combination of seasonal and diurnal
variability, as well as the five-day image acquisition interval.
The landscape around the ice cap supports tremendous biodiversity,
due largely to meltwater storage in down-valley lakes and wetlands
(bofedales). As the volume of runoff decreases, the many species
dependent upon the water are needing to adapt or relocate.
Another change with biotic effects is the glacier-surface
morphology, which we have observed over the past two decades.
Quelccaya is where breeding by the world's only glacier-nesting bird
species has been observed, as described here, here, and here. These Glacier Finch
(Idiopsar speculifer, formerly known as White-winged Diuca Finch,
Diuca speculifera) will only build nests in crevasses and very
steep, fissured margins - both of which tend to disappear as the
glacier has thinned and retreated.
We remain optimistic about returning in the next few years to this
amazing place, to document and measure changes since our last
visit!
