Posts
Amplifying
Feedbacks and the Arctic Heat Scream: Study Finds Polar Albedo
Falling at Twice Expected Rate, Added Heat Equal to 25% of
CO2 Forcing
19
February, 2014
What’s
the difference between a majestic layer of white sea ice and an
ominous dark blue open ocean?
For
the Arctic, it means about a 30 to 50% loss in reflectivity (or
albedo). And when seasonal sea ice states are between 30 and 80
percent below 1979 measures (depending on the method used to gauge
remaining sea ice and relative time of year), that means very, very
concerning additional heating impacts to an already dangerous
human-caused warming.
(A
dark and mostly ice-free Arctic Ocean beneath a tempestuous swirl of
clouds on September 1, 2012, a time when sea ice coverage had
declined to an area roughly equaled the land mass of Greenland. Image
source: Lance-Modis/NASA
AQUA.)
How
concerning, however, remained somewhat unclear until recently.
In
the past, idealized climate simulations and physical model runs had
produced about a 2% overall loss in Arctic Albedo based on observed
sea ice losses. This decline, though minor sounding, was enough, on
its own, to add a little more than a 10% amplifying feedback to the,
already powerful, human atmospheric CO2 forcing during recent years.
Such an addition was already cause for serious concern and with sea
ice totals continuing to fall rapidly, speculation abounded that just
this single mechanism could severely tip the scales toward a more
rapid warming.
But,
as has been the case with a number of Arctic model simulations
related to sea ice, these computer projections failed to measure up
to direct observation. In this case, direct satellite observation.
The situation is, therefore, once more, worse than expected.
A
new study produced by University of San Diego Scientists now
shows that loss of albedo for the Arctic Ocean due to rapidly
declining sea ice was 4% during the period of 1979 to 2011. This
amazing loss of reflectivity, on its own, created a powerful enough
heat trap to produce an amplifying feedback to human warming equal to
25% of the heat captured by CO2 emitted during that time. A feedback
double what we were led to expect from climate model simulations.
It
is important to step back for a moment and consider the implication
of this new information. If you took all the emissions from cars in
the world, all the buses, all the aircraft, all the land use CO2
emissions, all the agriculture, and all the amazing extra atmospheric
heat capture that an emission equal to 160 times that of all the
volcanoes on Earth would entail and added it all together, just one
insult to our natural world in the form of Arctic sea ice loss has
now equaled a 25% addition to that amazing total. Or just add enough
extra heat equal to 40 times the CO2 emitted by Earth’s volcanoes
(for a total of x 200).
Such
an increase is a very big deal and will have strong implications
going forward that affect the overall pace of human caused warming
and the degree to which we might contain ultimate temperature rises
under a scenario of full mitigation.
From
the study contents:
We find that the Arctic planetary albedo has decreased from 0.52 to 0.48 between 1979 and 2011, corresponding to an additional 6.4 ± 0.9 W/m2 of solar energy input into the Arctic Ocean region since 1979. Averaged over the globe, this albedo decrease corresponds to a forcing that is 25% as large as that due to the change in CO2 during this period, considerably larger than expectations from models and other less direct recent estimates.
It
is worth noting that the period measured by the study did not include
the unprecedented sea ice area, extent and volume losses seen during
2012. So it is likely that albedo loss and related Arctic additions
to human warming are somewhat worse than even this study suggests.
No
Way Out Through Increasing Cloud Cover
The
study also found that:
Changes in cloudiness appear to play a negligible role in observed Arctic darkening, thus reducing the possibility of Arctic cloud albedo feedbacks mitigating future Arctic warming.
Though
seemingly innocuous, this statement is a death knell for one proposed
method of Geo-engineering — namely cloud generation via spray ships
deployed throughout the Arctic basin. The proposal had suggested that
numerous ships could be spread about the Arctic during summer. These
ships would be equipped with large machines that would dip into the
ocean and spray sea water into the atmosphere to form clouds. The
notion was that this would somehow increase albedo. Proponents of the
plan neglected to provide scientific evidence that such a scheme
would actually work or wouldn’t make matters worse by increasing
atmospheric water vapor content — a substance with known
heat-trapping properties.
(Conceptual
drawing of an Arctic cloud-producing ship. Image
source: Geo-engineering
Watch.)
Others
had hoped a cloudier Arctic would take care of itself by producing a
negative feedback naturally. Numerous studies have found that an
Arctic with less sea ice is a much stormier, cloudier Arctic. And a
number of specialists and enthusiasts hinted that the extra clouds
would provide some cooling.
Not
so according to the San Diego study. And this makes sense as clouds,
while reflective of direct radiation contain large quantities of
heat-trapping water vapor and tend to also trap long-wave radiation —
which is more prevalent in the Arctic due to low angle of light or
extended periods of darkness.
Extraordinarily
Rapid Arctic Amplification
Despite
the various hollow conjectures and reassurances, what we have seen
over the past seven years or so is an extraordinarily rapid
amplification of heat within the Arctic. Arctic sea ice continues its
death spiral, hitting new record lows at various times at least once
a year. Heat keeps funneling into the Arctic, resulting in heatwaves
that bring 90 degree temperatures to Arctic Ocean shores during
summer and unprecedented Alaskan melts during January. We have seen
freakish fires in regions previously covered by tundra. Fires that
are the size of states in the Yakutia region of Russia, Alaska and
Canada. Fires in Arctic Norway during winter time. And we see periods
during winter when sea ice goes through extended stretches of
melt, as
we did just last week in the region of Svalbard.
One
need only look at the temperature anomaly map for the last 30 days to
know that something is dreadfully, dreadfully wrong with the Arctic:
(Global
temperature anomaly vs the, already warmer than normal, 1981 to 2010
baseline. Image source: NOAA/Earth
Systems Research Laboratory.)
And
one need only begin to add the number of amplifying feedbacks in the
Arctic together to start to understand how much trouble we’ve set
for ourselves:
- Arctic albedo decrease due to sea ice loss.
- Arctic CO2 release due to thawing tundra.
- Arctic methane release due to thawing land tundra.
- Arctic methane release due to thawing subsea tundra and venting seabed methane.
- Arctic albedo loss due to black carbon deposition.
- Arctic albedo loss due to land vegetation changes.
- Warming Arctic seas due to current changes.
- Warming Arctic seas due to runoff from warming lands.
- Arctic albedo decrease due to land snow and ice sheet melt.
- South to north heat transfer to the Arctic due to a weakening, retreating Jet Stream and increasing prevalence of high amplitude atmospheric waves.
We
all know, intuitively what an amplifying feedback sounds like. Just
hold a microphone closer to a speaker and listen to the rising wail
of sound. And it is becoming ever more obvious with each passing day,
with each new report that the Arctic is simply screaming to us.
How
deaf are we? How deaf are those of us who continue to fail to listen?
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