The findings of two studies
published in January, 2019 indicate that Antarctic’s ice had been melting “at
an alarming rate” since 1979.[1] The rate of melting looked at precisely tells
part of the story of why people in general were even in the year before 2020
still catching up in realizing the full extent to which climate change was
going on. The key here is the concept of acceleration.
The rate of ice loss has not been consistent in that ice disappeared faster in
each successive decade.
Specifically, ice loss in
Antarctica increased from 40 gigatons (a gigaton is one billion tons) per year
from 1979-90 to 252 gigatons per year from 2009-17. That’s a six-fold increase
in the rate of acceleration. In fact, the melt-rate accelerated most in the
most latter decade. The last two decades saw a melt-rate up 280% compared to
the first two decades. This change in the rate of change is extremely difficult
to grasp; it is like trying to watch for changes in the rate of acceleration in
your car. Paired with this greater difficulty is the fact that the problem is
not getting worse at a constant rate; rather, the getting-worse is itself
accelerating. The change occurring during the studies’ time-frame of four
decades was also difficult to notice because it was being caused by deep
relatively warm water hitting the bottom of the glaciers in east Antarctica;
the ice-changed-to-water was going on below.[2]
Whereas the Arctic’s ice is
over water, the Antarctic’s ice is generally over land so the additional water
raises sea levels more. Yet that won’t stop that water from raising the
Atlantic Ocean off Miami in Florida, and sooner
rather than later taking up about a third of the present peninsula. Given
the very significant population in southeast Florida, that the land there would
more likely be underwater sooner than
anticipated increases the changes of emergency situations, such as mass
relocations. In other words, the studies imply that we as a species could be
caught off-guard both from not having kept up on the accelerating rates and the
effects of those rates in bringing climate change sooner than would be the case
had the rates been constant across the decades. A feedback-loop could develop
whereby increasing rates trigger changes that in turn increase the rates even
more than otherwise. The situation could at that point be out of humanity’s
hands, yet the insufficient action while it can still make a difference has
been caused in part because an increasing rate of change is difficult for
humans to grasp, let alone see.
1, Brandon Miller, “Antarctica
Ice Melt Has Accelerated by 280% in the Last Four Decades,” cnn.com,
January 14, 2109. On holes in a glacier in Antartica, see Sheena McKinsey, "Gigantic Hole Two-Thirds the Size of Manhattan Discovered in Antartic Glacier," CNN.com (accessed January 31, 2019).
2. Eric Rignot et al, “Four Decades of
Antarctic Ice Sheet Mass Balance from 1979-2017,” PNAS, January 14, 2019.
