Fascinating input. Scary. Good input but spoiled gratuitously. I take exception
to the gratuitous comment in the second paragraph of 'human driven' cause
ignoring the fact that it not scientifically proven that global warming is
human driven and because it has been warming on average for 10,000 years
without enough humans or CO2 around to make a difference; AND there are cycles
of warming and cooling overlaying the general warming trend. One can have an
opinion, FINE, but opinion does not substitute for proven science and the
theory of CO2-driven global warming clearly remains to be proven using the
accepted scientific process. Science is not an election and AGW remains to be
proven. until it is proven it remains a not so robust hypothesis. Why is that
so hard to understand? Is it debatable?
----- Original Message -----
From: "Andrew Revkin " < revkin @ gmail .com>
To: " Geoengineering " < Geoengineering @ googlegroups .com>
Cc: "Ken Caldeira " < kcaldeira @ carnegiescience . edu >
Sent: Thursday, September 20, 2012 4:44:18 PM
Subject: [ geo ] Geo-engineering and Arctic mentioned here.
September 20, 2012, 3:57 PM Comment Pondering the Path To an Open Polar Sea
By ANDREW C. REVKIN
In the mid 1800s, some scientists and explorers — having not yet found a way
through the forbidding sea ice sheathing much of the Arctic Ocean — posited
that there was an “ open polar sea ” beyond those barricades, nourished by warm
waters sweeping north past Scandinavian coasts. (I have the marvelous 1867 book
“The Open Polar Sea” on my book shelf; you can read it online here .)
Now, it has become almost routine in summers to have broad stretches of the
Arctic Ocean largely free of ice. Global warming from the human-driven
buildup of heat-trapping greenhouse gases is seen by virtually all Arctic
scientists as playing a growing role in driving the shift in summers toward a
largely open sea at the top of the world, with plenty of variations along the
way.
As the National Snow and Ice Data Center announced yesterday , Sept. 16 marked
the end of the 2012 ice retreat, which far surpassed the ice melt in 2007 — at
the time considered a jaw-dropping outlier by many researchers . Here’s one
snippet from the center’s helpful release :
The six lowest seasonal minimum ice extents in the satellite record have all
occurred in the last six years (2007 to 2012). In contrast to 2007, when
climatic conditions (winds, clouds, air temperatures) favored summer ice loss,
this year’s conditions were not as extreme. Summer temperatures across the
Arctic were warmer than average, but cooler than in 2007. The most notable
event was a very strong storm centered over the central Arctic Ocean in early
August. [ The NASA video above shows how the storm winds centered on the ice
pack. Here's my post on that storm .] It is likely that the primary reason
for the large loss of ice this summer is that the ice cover has continued to
thin and become more dominated by seasonal ice. This thinner ice was more prone
to be broken up and melted by weather events, such as the strong low pressure
system just mentioned. The storm sped up the loss of the thin ice that appears
to have been already on the verge of melting completely.
Justin Gillis has a news story describing the findings and some
interpretations . There’s much more coverage , of course, and plenty of
messaging from green groups .
The first question is why was this year so surprisingly extreme, even along a
trend toward more open water? (Other questions will be addressed in the next
few days.) Overall, as I’ ve said for years, it’s the trend that matters most.
Otherwise you can end up in endless seesaw debates about what’s going on — with
this recent Skeptical Science graph demonstrating the importance of a longer
view:
arctic ice graphSkeptical Science A graph of September Arctic sea ice extent
(blue diamonds) with “recovery” years highlighted in red, versus the long-term
sea ice decline fit with a second order polynomial, also in red.
In the next 24 hours, I’ll be posting fresh excerpts from an extended and
fascinating discussion of ice patterns since 2007 involving some of the world’s
top ice researchers — both modelers and field scientists like those I
accompanied in 2003 on their annual North Pole expedition undertaken to
monitor the vital signs of the ocean beneath the drifting sea ice.
The pace of ice loss — both its extent and the amount of the older, thicker ice
that survives from summer to summer — has been faster than most models
predicted and clearly has, as a result, unnerved some polar researchers by
revealing how much is unknown about ice behavior in a warming climate.
Even with this year’s extreme loss, there’s still a wide range of predictions
among polar scientists of how soon the northernmost ocean will be “ice free” in
late summer. Peter Wadhams , a British oceanographer who’s charted ice
conditions for many years , is an outlier in p redicting 2015 or so (he has
joined an assortment of people calling for emergency geo -engineering efforts
to chill the Arctic).
But most of the dozen or so ice scientists I’ ve consulted of late (and several
dozen since 2000) remain closer in their views to Cecilia Bitz of the
University of Washington, who recently agreed with my notion (as a longtime,
but lay, observer) that there’s “ a 50-50 chance it will take a few decades .”
(Keep in mind that almost all Arctic sea ice researchers add a big caveat when
talking of an “ice-free Arctic Ocean,” noting that a big region of thick floes
north and west of Greenland will almost surely persist in summers through this
century, which is one reason some scientists have proposed targeting polar
bear conservation efforts there.)
It’s clear to a range of scientists that the enormous loss of old, thick ice
carried on currents from the Arctic out past Greenland into the Atlantic Ocean
in recent years is a major factor that has led to sharp summer melting. (With
the ocean cloaked mainly in relatively thin floes, formed over a single winter,
the chances rise each summer of a big melt-off under the 24-hour sun and
influxes of warmer seawater.) The forces driving that ice exodus are
complicated, as you’ll hear from the scientists contributing below.
This animated, three-dimensional graph, created by an amateur Arctic watcher,
Andy Lee Robinson, using data from the Piomas model of scientists at the
University of Washington, gives an incredibly interesting view of how the
reduction in overall ice volume has proceeded:
I asked Robinson, who is an engineer, graphics and programming expert and
musician, to explain the steps and sources behind the graph. Click here for my
Slideshare posting of his detailed reply .
While you wait for the exchange with ice researchers, I encourage you to
explore the developing string of posts by Judith Curry of Georgia Tech, who led
one of several research groups recently reporting links between summer ice
loss and severe winter weather in temperate regions of the Northern Hemisphere
(her relevant paper is here ). Her first post explored this question: “How
should we interpret the record low minimum sea ice extent?” Her second asked:
“Whence an ‘ice free’ Arctic? Does an ‘ice free’ Arctic matter?”
Also, you can start by exploring an illustrated view of the array of factors –
from sea-bottom topography to warm water – that may be in play in the changing
Arctic Ocean provided by James Morison of the University of Washington.
Morison has been studying Arctic sea ice and waters for decades and runs an
annual expedition to the North Pole to drop instruments through the ice into
the ocean below (the one I got to go on in 2003 ). He stresses this is
informed speculation at this point, putting him in good company considering the
many ideas in circulation and the persistent uncertainties in the system.
An Arctic Expert’s View of the Great Ice Melt of 2012 from Andrew Revkin
4:37 p.m. | Postscript | The scope of what’s unfolding, and the fascinating
and persistent science and policy questions, make me think I need to update and
expand my prize-winning book on the once and future Arctic, “The North Pole
Was Here.” Thoughts welcome. The first chapter is online here.
•
--
_
ANDREW C. REVKIN
Dot Earth blogger , The New York Times
http :// www . nytimes .com/ dotearth
Senior Fellow, Pace Acad . for Applied Env . Studies
Cell: 914-441-5556 Fax: 914-989-8009
Twitter: @ revkin Skype : Andrew. Revkin
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