New Crack Found in Delaware-Sized Chunk of Larsen C Ice Shelf as it Heads Toward Southern Ocean
A
2,000 square mile section of the Larsen C Ice Shelf is
hanging by a thread as it continues to drift toward the Weddell Sea.
4
May, 2017
The
break-off section represents
fully 10 percent of all the ice contained in the Larsen C system.
It has been divided from the larger ice shelf by a 180 kilometer long
crack that began to develop in 2009 and that swiftly lengthened
during recent years. Now only a 10 kilometer wide bridge links the
breaking section to the larger ice shelf. And considering the
enormous stresses now being placed on this break-off section it is
expected to go at any time.
Since
January, according
to researchers at Project MIDAS,
the large crack has been widening but its length growth has stalled.
However, recent
reports out this week from MIDAS found
that a new crack had developed at the ice-bridge end of the break-off
section. The new crack appears to be rounding the corner of the
bridge to begin a quicker path to segmenting the massive ice berg
away from Larsen C. A testament to the powerful forces that are
inevitably forcing this enormous section of ice to relinquish its
hold.
(Large
section of Larsen C is moving far faster than the rest of the ice
shelf toward the Southern Ocean. Image source: Project
MIDAS.)
At
issue is the fact that the break-off section is moving toward the
Weddell Sea considerably faster than the rest of the Larsen C ice
shelf. Much of this large section of ice is proceeding away from the
Antarctic mainland at 3 meters per day. Surrounding sections of
Larsen C are moving at only 1-2 meters per day. As a result, the toe
end of the break-off mass is tipping out into Weddell’s waters and
the crack separating it from Larsen C is widening.
It’s
not really a question of if this massive block of ice will separate
from Larsen C. More an issue of how soon.
Loss
of so large a section of ice from Larsen C threatens the entire ice
shelf’s stability. And some scientists are questioning whether the
whole ice shelf will destabilize and eventually splinter — as
happened to Larsen A and Larsen B during recent years.
(Rapid
loss of buttressing ice shelves like Larsen C lock in higher and
higher ranges for sea level rise. A worrying risk for rapid sea level
rise occurs as global temperatures warm to between 1.5 and 2.5 C. A
level we are fast approaching. Scientists like James Hansen identify
a significant risk for multi-meter sea level rise this Century if 2 C
warming thresholds are breached. Video Source: Carbon
Freeze.)
Warming
ocean waters due to human-forced climate change are the primary
driver for loss of ice shelves around the world. These ice shelves
hold back land glaciers — preventing them from more rapidly sliding
into the world’s oceans. Larsen
C alone holds back glaciers capable of lifting global ocean levels by
4 inches.
But there are numerous such ice shelves and many are now facing
thinning and increasing instability due to warming ocean waters. As a
result, a growing number of scientists are concerned about the
possibility for multi-meter sea level rise this Century if fossil
fuel burning is not swiftly halted.
Links:
Hat
tip to June
Hat
tip to Andy in San Diego
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