A recent paper in the journal Science by Anton Baks et. al.
has studied the effects of past climate warming on the planet’s permafrost and
concluded that a 1.5˚C global rise in
temperatures over the long term baseline will create a significant weakening
of the permafrost. We’re already halfway there (0.8˚C) and will hit that target
by mid-century.
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| Permafrost cracking pattern in the high Arctic. Photo credit: Brocken Inaglory via Wikimedia Commons |
When the permafrost melts, the buried plant matter is exposed to
sunlight (UV rays in particular), the the process of bacteria converting that
stored carbon to CO2 and methane accelerates, releasing perhaps 40% of these
greenhouse gases into the atmosphere. That can’t be good, no matter what.
Just how bad it is, however, is still scientifically uncertain, as is
the rate of warming up there.
On “just how bad it is,” there are mitigating factors. One, the
bacteria convert a lot of the biomass to CO2 which is much less threatening
than methane. No one knows what that ration will be, but the scary articles
usually assume its all methane. Not so. Two, the process takes time – decades will
pass between the arrival of the warming and the actual increase in atmospheric
heat trapped as a result. By that time, the total greenhouse gas releases from
all the usual suspects may drown out the permafrost contribution.
On the rate of change front, however, there is plenty of reason to
worry. Studies by NASA in 2012 indicate that the permafrost is melting much
faster than the global average – in fact, they’ve already risen by 2.2-3.9
degrees C (or 4-7 degrees F) over the last century. Another study shows that
the actual recorded rises in methane and CO2 over the world’s permafrost is
much, much greater than predictions by the IPCC and others. One thing we’re
certainly learned from three decades or so of climate predictions is: the consensus
is always low, and often very low, compared to what actually shows up.
We need more study on the permafrost front, certainly. My takeaway is
this: it’s one more time bomb ready to go off, and when you add up all the
similarly under-studied and under-reported time bombs (melting of the glaciers
comes to mind), we need to be very, very worried. Even if the odds are low, it’s
the only planet we have and we can’t afford to guess wrong.
