Spy Satellites
Recently declassified images taken by U.S. Cold
War spy satellites have proved surprisingly helpful
to glaciologists. Photos like the one to the left, from
the border of India and Nepal in December 1975,
are a snapshot of the past extent of the Himalayan
glaciers. In a June study in Science Advances,
researchers used the multi-angle observations of
these spy films to build a 3D model of the region in
the last quarter of the 20th century. Their analysis
shows that the Himalayas have lost twice as much
ice in the last two decades as they did between
1975 and 2 000.Death of a Glacier
What’s left of the first Icelandic glacier lost to climate change, pictured
above in 2018, was commemorated in 2019 with a memorial plaque.
Glaciologist Oddur Sigurðsson declared Okjökull a glacier-no-more back
in 2014, when the ice became too thin for glacial movement. But it wasn’t
until 2019 that members of the Icelandic Hiking Society, Rice University
and the general public installed the monument at its former site. The
August induction of the memorial followed the publication of an April
Nature study that attributes 25 to 30 percent of the observed global mean
sea level rise between 1993 and mid-2014 to glacier melting.FRO
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JANUARY/FEBRUARY 2020. DISCOVER 29Plaque installed in August 2019 at the site
of former glacier Okjökull. It reads:
A letter to the future
Ok is the first Icelandic glacier to lose its status as
a glacier. In the next 200 years all our glaciers are
expected to follow the same path. This monument is
to acknowledge that we know what is happening and
what needs to be done. Only you know if we did it.
August 201 9
415 ppm CO 2